Repository navigation
Expand file tree
/
Copy pathusage.html
More file actions
3004 lines (2897 loc) · 340 KB
/
Copy pathusage.html
File metadata and controls
3004 lines (2897 loc) · 340 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>The Argparse4j User Manual — argparse4j 0.9.0 documentation</title>
<link rel="stylesheet" href="_static/pygments.css" type="text/css" />
<link rel="stylesheet" href="_static/classic.css" type="text/css" />
<link rel="stylesheet" type="text/css" href="_static/default2.css" />
<script id="documentation_options" data-url_root="./" src="_static/documentation_options.js"></script>
<script src="_static/jquery.js"></script>
<script src="_static/underscore.js"></script>
<script src="_static/doctools.js"></script>
<link rel="index" title="Index" href="genindex.html" />
<link rel="search" title="Search" href="search.html" />
<link rel="next" title="Examples" href="examples.html" />
<link rel="prev" title="Argparse4j - The Java command-line argument parser library" href="index.html" />
</head><body>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="examples.html" title="Examples"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="index.html" title="Argparse4j - The Java command-line argument parser library"
accesskey="P">previous</a> |</li>
<li class="nav-item nav-item-0"><a href="index.html">argparse4j 0.9.0 documentation</a> »</li>
<li class="nav-item nav-item-this"><a href="">The Argparse4j User Manual</a></li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<div class="section" id="the-argparse4j-user-manual">
<h1>The Argparse4j User Manual<a class="headerlink" href="#the-argparse4j-user-manual" title="Permalink to this headline">¶</a></h1>
<p>Argparse4j is a command line argument parser library for Java based on
Python’s <a class="reference external" href="https://docs.python.org/3/library/argparse.html">argparse</a>
module. Because of the difference of language features, we cannot use
same syntax and usage of original, but we have tried to bring the same
touch and feel as much as possible. We also use same terminology as
much as possible.</p>
<p>This manual was written based on argparse’s manual and most of the the
sentences are almost identical, just replaced code examples. We use
this approach because argparse manual is well written and since both
are do the same thing, using existing manual makes us create a manual
with good quality in a short time. Thanks to Python community for the
great module and documentation.</p>
<p>We omitted package names from Java classes in this documentation for
readability because they tend to be quite long. Most Java programmers
use IDE (e.g., eclipse) and it has powerful auto-completion
features. And each class in argparse4j has unique name so it is not a
big problem after all. The <code class="docutils literal notranslate"><span class="pre">import</span></code> statements are also omitted from
the code snippet by the same reason.</p>
<div class="section" id="examples">
<h2>Examples<a class="headerlink" href="#examples" title="Permalink to this headline">¶</a></h2>
<p>The following code is a Java program that takes a list of integers
and produces either the sum or the max:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">class</span> <span class="nc">Prog</span> <span class="p">{</span>
<span class="kd">private</span> <span class="kd">static</span> <span class="kd">interface</span> <span class="nc">Accumulate</span> <span class="p">{</span>
<span class="kt">int</span> <span class="nf">accumulate</span><span class="p">(</span><span class="n">Collection</span><span class="o"><</span><span class="n">Integer</span><span class="o">></span> <span class="n">ints</span><span class="p">);</span>
<span class="p">}</span>
<span class="kd">private</span> <span class="kd">static</span> <span class="kd">class</span> <span class="nc">Sum</span> <span class="kd">implements</span> <span class="n">Accumulate</span> <span class="p">{</span>
<span class="nd">@Override</span>
<span class="kd">public</span> <span class="kt">int</span> <span class="nf">accumulate</span><span class="p">(</span><span class="n">Collection</span><span class="o"><</span><span class="n">Integer</span><span class="o">></span> <span class="n">ints</span><span class="p">)</span> <span class="p">{</span>
<span class="kt">int</span> <span class="n">sum</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span>
<span class="k">for</span> <span class="p">(</span><span class="n">Integer</span> <span class="n">i</span> <span class="p">:</span> <span class="n">ints</span><span class="p">)</span> <span class="p">{</span>
<span class="n">sum</span> <span class="o">+=</span> <span class="n">i</span><span class="p">;</span>
<span class="p">}</span>
<span class="k">return</span> <span class="n">sum</span><span class="p">;</span>
<span class="p">}</span>
<span class="nd">@Override</span>
<span class="kd">public</span> <span class="n">String</span> <span class="nf">toString</span><span class="p">()</span> <span class="p">{</span>
<span class="k">return</span> <span class="n">getClass</span><span class="p">().</span><span class="na">getSimpleName</span><span class="p">();</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="kd">private</span> <span class="kd">static</span> <span class="kd">class</span> <span class="nc">Max</span> <span class="kd">implements</span> <span class="n">Accumulate</span> <span class="p">{</span>
<span class="nd">@Override</span>
<span class="kd">public</span> <span class="kt">int</span> <span class="nf">accumulate</span><span class="p">(</span><span class="n">Collection</span><span class="o"><</span><span class="n">Integer</span><span class="o">></span> <span class="n">ints</span><span class="p">)</span> <span class="p">{</span>
<span class="k">return</span> <span class="n">Collections</span><span class="p">.</span><span class="na">max</span><span class="p">(</span><span class="n">ints</span><span class="p">);</span>
<span class="p">}</span>
<span class="nd">@Override</span>
<span class="kd">public</span> <span class="n">String</span> <span class="nf">toString</span><span class="p">()</span> <span class="p">{</span>
<span class="k">return</span> <span class="n">getClass</span><span class="p">().</span><span class="na">getSimpleName</span><span class="p">();</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">()</span>
<span class="p">.</span><span class="na">description</span><span class="p">(</span><span class="s">"Process some integers."</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"integers"</span><span class="p">)</span>
<span class="p">.</span><span class="na">metavar</span><span class="p">(</span><span class="s">"N"</span><span class="p">)</span>
<span class="p">.</span><span class="na">type</span><span class="p">(</span><span class="n">Integer</span><span class="p">.</span><span class="na">class</span><span class="p">)</span>
<span class="p">.</span><span class="na">nargs</span><span class="p">(</span><span class="s">"+"</span><span class="p">)</span>
<span class="p">.</span><span class="na">help</span><span class="p">(</span><span class="s">"an integer for the accumulator"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--sum"</span><span class="p">)</span>
<span class="p">.</span><span class="na">dest</span><span class="p">(</span><span class="s">"accumulate"</span><span class="p">)</span>
<span class="p">.</span><span class="na">action</span><span class="p">(</span><span class="n">Arguments</span><span class="p">.</span><span class="na">storeConst</span><span class="p">())</span>
<span class="p">.</span><span class="na">setConst</span><span class="p">(</span><span class="k">new</span> <span class="n">Sum</span><span class="p">())</span>
<span class="p">.</span><span class="na">setDefault</span><span class="p">(</span><span class="k">new</span> <span class="n">Max</span><span class="p">())</span>
<span class="p">.</span><span class="na">help</span><span class="p">(</span><span class="s">"sum the integers (default: find the max)"</span><span class="p">);</span>
<span class="k">try</span> <span class="p">{</span>
<span class="n">Namespace</span> <span class="n">res</span> <span class="o">=</span> <span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">args</span><span class="p">);</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(((</span><span class="n">Accumulate</span><span class="p">)</span> <span class="n">res</span><span class="p">.</span><span class="na">get</span><span class="p">(</span><span class="s">"accumulate"</span><span class="p">))</span>
<span class="p">.</span><span class="na">accumulate</span><span class="p">((</span><span class="n">List</span><span class="o"><</span><span class="n">Integer</span><span class="o">></span><span class="p">)</span> <span class="n">res</span><span class="p">.</span><span class="na">get</span><span class="p">(</span><span class="s">"integers"</span><span class="p">)));</span>
<span class="p">}</span> <span class="k">catch</span> <span class="p">(</span><span class="n">ArgumentParserException</span> <span class="n">e</span><span class="p">)</span> <span class="p">{</span>
<span class="n">parser</span><span class="p">.</span><span class="na">handleError</span><span class="p">(</span><span class="n">e</span><span class="p">);</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="p">}</span>
</pre></div>
</div>
<p>It can be run at the command line and provides useful help messages:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Prog -h
<span class="go">usage: prog [-h] [--sum] N [N ...]</span>
<span class="go">Process some integers.</span>
<span class="go">positional arguments:</span>
<span class="go"> N an integer for the accumulator</span>
<span class="go">named arguments:</span>
<span class="go"> -h, --help show this help message and exit</span>
<span class="go"> --sum sum the integers (default: find the max)</span>
</pre></div>
</div>
<p>When run with the appropriate arguments, it prints either the sum or
the max of the command-line integers:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Prog <span class="m">1</span> <span class="m">2</span> <span class="m">3</span> <span class="m">4</span>
<span class="go">4</span>
<span class="gp">$ </span>java Prog <span class="m">1</span> <span class="m">2</span> <span class="m">3</span> <span class="m">4</span> --sum
<span class="go">10</span>
</pre></div>
</div>
<p>If invalid arguments are passed in, it will throw an exception. The
user program can catch the exception and show error message:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Prog a b c
<span class="go">usage: prog [-h] [--sum] N [N ...]</span>
<span class="go">prog: error: argument integers: could not construct class java.lang.Integer from a (For input string: "a")</span>
</pre></div>
</div>
<p>The following sections walk you through this example.</p>
<div class="section" id="creating-a-parser">
<h3>Creating a parser<a class="headerlink" href="#creating-a-parser" title="Permalink to this headline">¶</a></h3>
<p>The first step using the argparse4j is creating
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html"><span class="pre">ArgumentParser</span></a></code> object. To do this, use
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParsers.html#newFor(java.lang.String)"><span class="pre">ArgumentParsers.newFor()</span></a></code> static method of <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParsers.html"><span class="pre">ArgumentParsers</span></a></code>
class. This will return a builder for the parser. (Note: Prior to
0.8.0 an ArgumentParser object was created using
<code class="docutils literal notranslate"><span class="pre">newArgumentParser(...)</span></code> methods of <code class="docutils literal notranslate"><span class="pre">ArgumentParsers</span></code>. See
<a class="reference internal" href="migration.html"><span class="doc">Migration</span></a>.) Use method <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParserBuilder.html#build()"><span class="pre">ArgumentParserBuilder.build()</span></a></code> to create
the parser:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">()</span>
<span class="p">.</span><span class="na">description</span><span class="p">(</span><span class="s">"Process some integers."</span><span class="p">);</span>
</pre></div>
</div>
<p>The <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html"><span class="pre">ArgumentParser</span></a></code> object will hold all the information
necessary to parse the command line into Java data types.</p>
<p>Since 0.9.0 there is a variant of <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParsers.html#newFor(java.lang.String,net.sourceforge.argparse4j.DefaultSettings)"><span class="pre">ArgumentParsers.newFor()</span></a></code>
that allows you to choose of which version the defaults for
configuration settings must be used. This makes it easy to use all
improvements of a specific version without having to change all
configuration settings individually:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">,</span> <span class="n">DefaultSettings</span><span class="p">.</span><span class="na">VERSION_0_9_0_DEFAULT_SETTINGS</span><span class="p">)</span>
<span class="p">.</span><span class="na">build</span><span class="p">()</span>
<span class="p">.</span><span class="na">description</span><span class="p">(</span><span class="s">"Process some integers."</span><span class="p">);</span>
</pre></div>
</div>
<p>The following versions have default settings that differ from the
previous version:</p>
<ul class="simple">
<li><dl class="simple">
<dt>0.9.0</dt><dd><ul>
<li><p>The help text for a mutually-exclusive group will include an
extra paragraph explaining that at most 1 argument of that
group may be given:
<a class="reference internal" href="#argumentparserbuilder-musthelptextincludemutualexclusivity"><span class="std std-ref">mustHelpTextIncludeMutualExclusivity</span></a></p></li>
</ul>
</dd>
</dl>
</li>
</ul>
<p>When upgrading to a newer version of argparse4j the chosen defaults
will be honored, so the behavior of applications does not change
without the developer explicitly opting in to improvements.</p>
</div>
<div class="section" id="adding-arguments">
<span id="id1"></span><h3>Adding arguments<a class="headerlink" href="#adding-arguments" title="Permalink to this headline">¶</a></h3>
<p>Filling an ArgumentParser with information about program arguments is
done by making calls to the <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#addArgument(java.lang.String...)"><span class="pre">ArgumentParser.addArgument()</span></a></code> method.
Generally, this calls tell the ArgumentParser how to take the strings
on the command line and turn them into objects. This information is
stored and used when <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#parseArgs(java.lang.String[])"><span class="pre">ArgumentParser.parseArgs()</span></a></code> is called. For
example:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"integers"</span><span class="p">)</span>
<span class="p">.</span><span class="na">metavar</span><span class="p">(</span><span class="s">"N"</span><span class="p">)</span>
<span class="p">.</span><span class="na">type</span><span class="p">(</span><span class="n">Integer</span><span class="p">.</span><span class="na">class</span><span class="p">)</span>
<span class="p">.</span><span class="na">nargs</span><span class="p">(</span><span class="s">"+"</span><span class="p">)</span>
<span class="p">.</span><span class="na">help</span><span class="p">(</span><span class="s">"an integer for the accumulator"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--sum"</span><span class="p">)</span>
<span class="p">.</span><span class="na">dest</span><span class="p">(</span><span class="s">"accumulate"</span><span class="p">)</span>
<span class="p">.</span><span class="na">action</span><span class="p">(</span><span class="n">Arguments</span><span class="p">.</span><span class="na">storeConst</span><span class="p">())</span>
<span class="p">.</span><span class="na">setConst</span><span class="p">(</span><span class="k">new</span> <span class="n">Sum</span><span class="p">())</span>
<span class="p">.</span><span class="na">setDefault</span><span class="p">(</span><span class="k">new</span> <span class="n">Max</span><span class="p">())</span>
<span class="p">.</span><span class="na">help</span><span class="p">(</span><span class="s">"sum the integers (default: find the max)"</span><span class="p">);</span>
</pre></div>
</div>
<p>Later, calling <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#parseArgs(java.lang.String[])"><span class="pre">ArgumentParser.parseArgs()</span></a></code> will return an
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/Namespace.html"><span class="pre">Namespace</span></a></code> object with two attributes, <code class="docutils literal notranslate"><span class="pre">integers</span></code> and
<code class="docutils literal notranslate"><span class="pre">accumulate</span></code>. The <code class="docutils literal notranslate"><span class="pre">integers</span></code> attribute will be a
<code class="xref docutils literal notranslate"><span class="pre">List<Integer></span></code> which has one or more ints, and the
<code class="docutils literal notranslate"><span class="pre">accumulate</span></code> attribute will be either the <code class="xref docutils literal notranslate"><span class="pre">Sum</span></code> object, if
<code class="docutils literal notranslate"><span class="pre">--sum</span></code> was specified at the command line, or the <code class="xref docutils literal notranslate"><span class="pre">Max</span></code>
object if it was not.</p>
</div>
<div class="section" id="passing-arguments">
<h3>Passing arguments<a class="headerlink" href="#passing-arguments" title="Permalink to this headline">¶</a></h3>
<p>ArgumentParser parses arguments through the
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#parseArgs(java.lang.String[])"><span class="pre">ArgumentParser.parseArgs()</span></a></code> method. This will inspect the command
line, convert each argument to the appropriate type and then invoke
the appropriate action. In most cases, this means a simple
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/Namespace.html"><span class="pre">Namespace</span></a></code> object will have attributes parsed out of the
command line. The following code:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="n">Namespace</span> <span class="n">res</span> <span class="o">=</span> <span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="k">new</span> <span class="n">String</span><span class="o">[]</span> <span class="p">{</span> <span class="s">"--sum"</span><span class="p">,</span> <span class="s">"7"</span><span class="p">,</span> <span class="s">"-1"</span><span class="p">,</span> <span class="s">"42"</span> <span class="p">});</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">res</span><span class="p">);</span>
</pre></div>
</div>
<p>will display:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="go">Namespace(integers=[7, -1, 42], accumulate=Sum)</span>
</pre></div>
</div>
<p>In Java, the command line arguments are typically given as <code class="docutils literal notranslate"><span class="pre">String[]</span>
<span class="pre">argv</span></code>. To parse the command line, pass this object to
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#parseArgs(java.lang.String[])"><span class="pre">ArgumentParser.parseArgs()</span></a></code> method.</p>
</div>
</div>
<div class="section" id="argumentparser-objects">
<h2>ArgumentParser objects<a class="headerlink" href="#argumentparser-objects" title="Permalink to this headline">¶</a></h2>
<p>To create <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html"><span class="pre">ArgumentParser</span></a></code> object, use
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParsers.html#newFor(java.lang.String)"><span class="pre">ArgumentParsers.newFor()</span></a></code> static method of
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParsers.html"><span class="pre">ArgumentParsers</span></a></code> class. This will return a builder for
the parser. The following parameter must be specified:</p>
<ul class="simple">
<li><p><a class="reference internal" href="#argumentparsers-newfor-prog"><span class="std std-ref">prog</span></a> - The name of the
program. This is necessary because <code class="docutils literal notranslate"><span class="pre">main()</span></code> method in Java does
not provide program name.</p></li>
</ul>
<p>Configure the parser to be build using methods of the builder:</p>
<ul class="simple">
<li><p><a class="reference internal" href="#argumentparserbuilder-addhelp"><span class="std std-ref">addHelp</span></a> - Add a -h/–help
option to the parser. (default: <code class="docutils literal notranslate"><span class="pre">true</span></code>).</p></li>
<li><p><a class="reference internal" href="#argumentparserbuilder-prefixchars"><span class="std std-ref">prefixChars</span></a> - The set of
characters that prefix named arguments. (default: ‘-‘)</p></li>
<li><p><a class="reference internal" href="#argumentparserbuilder-fromfileprefix"><span class="std std-ref">fromFilePrefix</span></a> - The
set of characters that prefix file path from which additional
arguments are read. (default: <code class="docutils literal notranslate"><span class="pre">null</span></code>)</p></li>
<li><p><a class="reference internal" href="#argumentparserbuilder-locale"><span class="std std-ref">locale</span></a> - The locale to use for
messages. (default: <code class="docutils literal notranslate"><span class="pre">Locale.getDefault()</span></code>)</p></li>
<li><p><a class="reference internal" href="#argumentparserbuilder-cjkwidthhack"><span class="std std-ref">cjkWidthHack</span></a> - Treat Unicode
characters having East Asian Width property Wide/Full/Ambiguous to
have twice a width of ascii characters when formatting help message
if locale is “ja”, “zh” or “ko”. (default: <code class="docutils literal notranslate"><span class="pre">true</span></code>)</p></li>
<li><p><a class="reference internal" href="#argumentparserbuilder-defaultformatwidth"><span class="std std-ref">defaultFormatWidth</span></a> - The default
width (in columns) for formatting messages. This value is used if
terminal width detection is disabled or fails. (default: <code class="docutils literal notranslate"><span class="pre">75</span></code>)</p></li>
<li><p><a class="reference internal" href="#argumentparserbuilder-terminalwidthdetection"><span class="std std-ref">terminalWidthDetection</span></a> - Detect the
width of the terminal the application is running in. If the
terminal width cannot be detected, the default format width is
used. (default: <code class="docutils literal notranslate"><span class="pre">true</span></code>)</p></li>
<li><p><a class="reference internal" href="#argumentparserbuilder-singlemetavar"><span class="std std-ref">singleMetavar</span></a> - Show the metavar
string in help message only after the last flag instead of each
flag. (default: <code class="docutils literal notranslate"><span class="pre">false</span></code>)</p></li>
<li><p><a class="reference internal" href="#argumentparserbuilder-includeargumentnamesaskeysinresult"><span class="std std-ref">includeArgumentNamesAsKeysInResult</span></a> -
Also add the argument name as a key in the result (if a value for
the argument will be added for <code class="docutils literal notranslate"><span class="pre">dest</span></code>). The argument name is the
name of positional arguments, and the first long flag, or otherwise
first flag, without the prefix for named arguments.</p></li>
<li><p><a class="reference internal" href="#argumentparserbuilder-musthelptextincludemutualexclusivity"><span class="std std-ref">mustHelpTextIncludeMutualExclusivity</span></a> -
Add a text after the description and before the arguments of a
mutually-exclusive group explaining that at most 1 of the arguments
may be given.</p></li>
<li><p><a class="reference internal" href="#argumentparserbuilder-nodestconversionforpositionalargs"><span class="std std-ref">noDestConversionForPositionalArgs</span></a> -
Do not perform any conversion to produce “dest” value from
positional argument name. (default: <code class="docutils literal notranslate"><span class="pre">false</span></code>)</p></li>
</ul>
<p>The parser is created using method
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParserBuilder.html#build()"><span class="pre">ArgumentParserBuilder.build()</span></a></code>.</p>
<p>After creation of the instance, several additional parameters can be
specified using following methods:</p>
<ul class="simple">
<li><p><a class="reference internal" href="#argumentparser-description"><span class="std std-ref">ArgumentParser.description()</span></a> - Text
to display before the argument help.</p></li>
<li><p><a class="reference internal" href="#argumentparser-epilog"><span class="std std-ref">ArgumentParser.epilog()</span></a> - Text to display after the argument
help.</p></li>
<li><p><a class="reference internal" href="#argumentparser-defaulthelp"><span class="std std-ref">ArgumentParser.defaultHelp()</span></a> - Display default value to help
message. (default: <code class="docutils literal notranslate"><span class="pre">false</span></code>)</p></li>
<li><p><a class="reference internal" href="#argumentparser-usage"><span class="std std-ref">ArgumentParser.usage()</span></a> - The string describing the program
usage (default: generated)</p></li>
<li><p><a class="reference internal" href="#argumentparser-version"><span class="std std-ref">ArgumentParser.version()</span></a> - The string describing the program
version.</p></li>
</ul>
<p>The following sections describes how each of these are used.</p>
<div class="section" id="prog">
<span id="argumentparsers-newfor-prog"></span><h3>prog<a class="headerlink" href="#prog" title="Permalink to this headline">¶</a></h3>
<p>In Java, the name of the program is not included in the argument in
<code class="xref py py-func docutils literal notranslate"><span class="pre">main()</span></code> method. Because of this, the name of the program must be
supplied to <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParsers.html#newFor(java.lang.String)"><span class="pre">ArgumentParsers.newFor()</span></a></code>.</p>
</div>
<div class="section" id="addhelp">
<span id="argumentparserbuilder-addhelp"></span><h3>addHelp<a class="headerlink" href="#addhelp" title="Permalink to this headline">¶</a></h3>
<p>By default, <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html"><span class="pre">ArgumentParser</span></a></code> objects add an option which
simply displays the parser’s help message. For example, consider
following code:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--foo"</span><span class="p">).</span><span class="na">help</span><span class="p">(</span><span class="s">"foo help"</span><span class="p">);</span>
<span class="n">Namespace</span> <span class="n">res</span> <span class="o">=</span> <span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">args</span><span class="p">);</span>
<span class="p">}</span>
</pre></div>
</div>
<p>If <code class="docutils literal notranslate"><span class="pre">-h</span></code> or <code class="docutils literal notranslate"><span class="pre">--help</span></code> is supplied at the command line, the
ArgumentParser will display help message:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo --help
<span class="go">usage: prog [-h] [--foo FOO]</span>
<span class="go">named arguments:</span>
<span class="go"> -h, --help show this help message and exit</span>
<span class="go"> --foo FOO foo help</span>
</pre></div>
</div>
<p>Occasionally, it may be useful to disable the addition of this help
option. This can be achieved by passing <code class="docutils literal notranslate"><span class="pre">false</span></code> as the
<a class="reference internal" href="#addhelp">addHelp</a> argument to <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParserBuilder.html#addHelp(boolean)"><span class="pre">ArgumentParserBuilder.addHelp()</span></a></code>:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span>
<span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">addHelp</span><span class="p">(</span><span class="kc">false</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--foo"</span><span class="p">).</span><span class="na">help</span><span class="p">(</span><span class="s">"foo help"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">printHelp</span><span class="p">();</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo
<span class="go">usage: prog [--foo FOO]</span>
<span class="go">named arguments:</span>
<span class="go"> --foo FOO foo help</span>
</pre></div>
</div>
<p>The help option is typically <code class="docutils literal notranslate"><span class="pre">-h/--help</span></code>. The exception to this is
if the <a class="reference internal" href="#argumentparserbuilder-prefixchars"><span class="std std-ref">prefixChars</span></a> is
specified and does not include <code class="docutils literal notranslate"><span class="pre">-</span></code>, in which case <code class="docutils literal notranslate"><span class="pre">-h</span></code> and
<code class="docutils literal notranslate"><span class="pre">--help</span></code> are not valid options. In this case, the first character in
<a class="reference internal" href="#argumentparserbuilder-prefixchars"><span class="std std-ref">prefixChars</span></a> is used to prefix
the help options:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span>
<span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">addHelp</span><span class="p">(</span><span class="kc">true</span><span class="p">).</span><span class="na">prefixChars</span><span class="p">(</span><span class="s">"+/"</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">printHelp</span><span class="p">();</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo
<span class="go">usage: prog [+h]</span>
<span class="go">named arguments:</span>
<span class="go"> +h, ++help show this help message and exit</span>
</pre></div>
</div>
</div>
<div class="section" id="prefixchars">
<span id="argumentparserbuilder-prefixchars"></span><h3>prefixChars<a class="headerlink" href="#prefixchars" title="Permalink to this headline">¶</a></h3>
<p>Most command line options will use <code class="docutils literal notranslate"><span class="pre">-</span></code> as the prefix, e.g.
<code class="docutils literal notranslate"><span class="pre">-f/--foo</span></code>. Parsers that need to support different or additional
prefix characters, e.g. for options like <code class="docutils literal notranslate"><span class="pre">+f</span></code> or <code class="docutils literal notranslate"><span class="pre">/foo</span></code>, may
specify them using the <em>prefixChars</em> to
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParserBuilder.html#prefixChars(java.lang.String)"><span class="pre">ArgumentParserBuilder.prefixChars()</span></a></code>:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">prefixChars</span><span class="p">(</span><span class="s">"-+"</span><span class="p">)</span>
<span class="p">.</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"+f"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"++bar"</span><span class="p">);</span>
<span class="n">Namespace</span> <span class="n">res</span> <span class="o">=</span> <span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">args</span><span class="p">);</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">res</span><span class="p">);</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo +f X ++bar Y
<span class="go">Namespace(f=X, bar=Y)</span>
</pre></div>
</div>
<p>The <em>prefixChars</em> argument defaults to <code class="docutils literal notranslate"><span class="pre">-</span></code> (you can use
<code class="xref docutils literal notranslate"><span class="pre">ArgumentParsers.DEFAULT_PREFIX_CHARS</span></code> for this). Supplying
a set of characters that does not include <code class="docutils literal notranslate"><span class="pre">-</span></code> will cause
<code class="docutils literal notranslate"><span class="pre">-f/--foo</span></code> options to be disallowed.</p>
</div>
<div class="section" id="fromfileprefix">
<span id="argumentparserbuilder-fromfileprefix"></span><h3>fromFilePrefix<a class="headerlink" href="#fromfileprefix" title="Permalink to this headline">¶</a></h3>
<p>It is sometimes useful to read arguments from file other than typing
them in command line, for example, when lots of arguments are needed.
If <em>fromFilePrefix</em> is given as non <code class="docutils literal notranslate"><span class="pre">null</span></code> string, arguments starts
with one of these characters are treated as file path and
ArgumentParser reads additional arguments from the file. For example:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>cat args.txt
<span class="go">-f</span>
<span class="go">bar</span>
</pre></div>
</div>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">)</span>
<span class="p">.</span><span class="na">fromFilePrefix</span><span class="p">(</span><span class="s">"@"</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"-f"</span><span class="p">);</span>
<span class="k">try</span> <span class="p">{</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">args</span><span class="p">));</span>
<span class="p">}</span> <span class="k">catch</span> <span class="p">(</span><span class="n">ArgumentParserException</span> <span class="n">e</span><span class="p">)</span> <span class="p">{</span>
<span class="n">parser</span><span class="p">.</span><span class="na">handleError</span><span class="p">(</span><span class="n">e</span><span class="p">);</span>
<span class="n">System</span><span class="p">.</span><span class="na">exit</span><span class="p">(</span><span class="mi">1</span><span class="p">);</span>
<span class="p">}</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo -f foo @args.txt
<span class="go">Namespace(f=bar)</span>
</pre></div>
</div>
<p>The each line of the file is treated as one argument. Please be aware
that trailing empty lines or line with only white spaces are also
considered as arguments, although it is not readily noticeable to the
user. The empty line is treated as empty string.</p>
<p>By default, <em>fromFilePrefix</em> is <code class="docutils literal notranslate"><span class="pre">null</span></code>, which means no argument is
treated as file path.</p>
</div>
<div class="section" id="locale">
<span id="argumentparserbuilder-locale"></span><h3>locale<a class="headerlink" href="#locale" title="Permalink to this headline">¶</a></h3>
<p>The locale for messages of <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html"><span class="pre">ArgumentParser</span></a></code> objects can
be changed by using <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParserBuilder.html#locale(java.util.Locale)"><span class="pre">ArgumentParserBuilder.locale()</span></a></code>. For example:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">)</span>
<span class="p">.</span><span class="na">locale</span><span class="p">(</span><span class="k">new</span> <span class="n">Locale</span><span class="p">(</span><span class="s">"nl"</span><span class="p">)).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">printHelp</span><span class="p">();</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo
<span class="go">gebruik: prog [-h]</span>
<span class="go">optionele argumenten:</span>
<span class="go"> -h, --help toon dit hulpbericht en sluit af</span>
</pre></div>
</div>
<p>Currently messages have been (partially) translated to Dutch,
English, German and Russian.</p>
<p>The default locale is the default locale of the JVM
(<code class="docutils literal notranslate"><span class="pre">Locale.getDefault()</span></code>). Upto 0.9.0 the fallback locale for the
argparse4j resource bundle was overridden to be “en_US”. Because of
the switch to named modules to support Java 9+, the override has been
removed.</p>
</div>
<div class="section" id="cjkwidthhack">
<span id="argumentparserbuilder-cjkwidthhack"></span><h3>cjkWidthHack<a class="headerlink" href="#cjkwidthhack" title="Permalink to this headline">¶</a></h3>
<p>A number of characters in Chinese, Japanese and Korean (CJK) are
wider than others. If those characters are treated to have the same
width as other characters, texts may extend past the right margin
when printed. By enabling the CJK width, 2 columns are used for these
wide characters during the determination of line breaks, resulting in
better formatted text. To enable or disable handling of wide CJK
characters use <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParserBuilder.html#cjkwidthHack(boolean)"><span class="pre">ArgumentParserBuilder.cjkwidthHack()</span></a></code>:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">)</span>
<span class="p">.</span><span class="na">cjkWidthHack</span><span class="p">(</span><span class="kc">false</span><span class="p">).</span><span class="na">build</span><span class="p">()</span>
<span class="p">...</span>
<span class="p">}</span>
</pre></div>
</div>
<p><em>cjkWidthHack</em> is <code class="docutils literal notranslate"><span class="pre">true</span></code> by default.</p>
</div>
<div class="section" id="defaultformatwidth">
<span id="argumentparserbuilder-defaultformatwidth"></span><h3>defaultFormatWidth<a class="headerlink" href="#defaultformatwidth" title="Permalink to this headline">¶</a></h3>
<p>Messages generated by <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html"><span class="pre">ArgumentParser</span></a></code> objects are
formatted to fit within a number of columns.
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParserBuilder.html#defaultFormatWidth(int)"><span class="pre">ArgumentParserBuilder.defaultFormatWidth()</span></a></code> can be used to set the
number of columns to use when
<a class="reference internal" href="#argumentparserbuilder-terminalwidthdetection"><span class="std std-ref">terminalWidthDetection</span></a> is disabled or
when the detection cannot determine the number of columns from the
environment:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">arguments</span><span class="p">)</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">)</span>
<span class="p">.</span><span class="na">defaultFormatWidth</span><span class="p">(</span><span class="mi">40</span><span class="p">).</span><span class="na">build</span><span class="p">()</span>
<span class="p">.</span><span class="na">description</span><span class="p">(</span>
<span class="s">"A program showing how argparse4j formats long messages."</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">printHelp</span><span class="p">();</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo
<span class="go">usage: prog [-h]</span>
<span class="go">A program showing how argparse4j</span>
<span class="go">formats long messages.</span>
<span class="go">...</span>
</pre></div>
</div>
<p>The default value for <em>defaultFormatWidth</em> is <code class="docutils literal notranslate"><span class="pre">75</span></code>.</p>
</div>
<div class="section" id="terminalwidthdetection">
<span id="argumentparserbuilder-terminalwidthdetection"></span><h3>terminalWidthDetection<a class="headerlink" href="#terminalwidthdetection" title="Permalink to this headline">¶</a></h3>
<p>Argparse4j tries to format messages so they fit the terminal the
application is running in. It does this by looking at environment
variable <code class="docutils literal notranslate"><span class="pre">COLUMNS</span></code>, or running <code class="docutils literal notranslate"><span class="pre">stty</span></code> on platforms that support
it. The detection can be enabled or disabled using
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParserBuilder.html#terminalWidthDetection(boolean)"><span class="pre">ArgumentParserBuilder.terminalWidthDetection()</span></a></code>. When disabling the
detection <a class="reference internal" href="#argumentparserbuilder-defaultformatwidth"><span class="std std-ref">defaultFormatWidth</span></a> is used as
the number of columns:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">)</span>
<span class="p">.</span><span class="na">terminalWidthDetection</span><span class="p">(</span><span class="kc">false</span><span class="p">).</span><span class="na">build</span><span class="p">()</span>
<span class="p">.</span><span class="na">description</span><span class="p">(</span>
<span class="s">"A program showing how argparse4j formats long messages. "</span> <span class="o">+</span>
<span class="s">"Terminal width detection has been disabled, "</span> <span class="o">+</span>
<span class="s">"so this description is formatted to 75 characters wide."</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">printHelp</span><span class="p">();</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo
<span class="go">usage: prog [-h]</span>
<span class="go">A program showing how argparse4j formats long messages. Terminal width</span>
<span class="go">detection has been disabled, so this description is formatted to 75</span>
<span class="go">characters wide.</span>
<span class="go">...</span>
</pre></div>
</div>
<p>By default <em>terminalWidthDection</em> is <code class="docutils literal notranslate"><span class="pre">true</span></code>.</p>
</div>
<div class="section" id="singlemetavar">
<span id="argumentparserbuilder-singlemetavar"></span><h3>singleMetavar<a class="headerlink" href="#singlemetavar" title="Permalink to this headline">¶</a></h3>
<p>The metavariable of an argument can be printed after each argument
name or only once after all argument names. This behavior is
controlled using <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParserBuilder.html#singleMetavar(boolean)"><span class="pre">ArgumentParserBuilder.singleMetavar()</span></a></code>. Here is an
example using a single metavariable:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"single"</span><span class="p">)</span>
<span class="p">.</span><span class="na">singleMetavar</span><span class="p">(</span><span class="kc">true</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"-f"</span><span class="p">,</span> <span class="s">"-file"</span><span class="p">).</span><span class="na">nargs</span><span class="p">(</span><span class="s">"+"</span><span class="p">).</span><span class="na">metavar</span><span class="p">(</span><span class="s">"FILE"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">printHelp</span><span class="p">();</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo
<span class="go">usage: single [-h] [-f FILE [FILE ...]]</span>
<span class="go">named arguments:</span>
<span class="go"> -h, --help show this help message and exit</span>
<span class="go"> -f, -file FILE [FILE ...]</span>
</pre></div>
</div>
<p>Compare this with the output if using multiple metavariables:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"multiple"</span><span class="p">)</span>
<span class="p">.</span><span class="na">singleMetavar</span><span class="p">(</span><span class="kc">false</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"-f"</span><span class="p">,</span> <span class="s">"-file"</span><span class="p">).</span><span class="na">nargs</span><span class="p">(</span><span class="s">"+"</span><span class="p">).</span><span class="na">metavar</span><span class="p">(</span><span class="s">"FILE"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">printHelp</span><span class="p">();</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo
<span class="go">usage: multiple [-h] [-f FILE [FILE ...]]</span>
<span class="go">named arguments:</span>
<span class="go"> -h, --help show this help message and exit</span>
<span class="go"> -f FILE [FILE ...], -file FILE [FILE ...]</span>
</pre></div>
</div>
<p><em>singleMetavar</em> defaults to <code class="docutils literal notranslate"><span class="pre">false</span></code>, so the metavariable is printed
after each argument name.</p>
</div>
<div class="section" id="includeargumentnamesaskeysinresult">
<span id="argumentparserbuilder-includeargumentnamesaskeysinresult"></span><h3>includeArgumentNamesAsKeysInResult<a class="headerlink" href="#includeargumentnamesaskeysinresult" title="Permalink to this headline">¶</a></h3>
<p>The <code class="docutils literal notranslate"><span class="pre">dest</span></code> value of an argument is used as a key in the parse
result. It is different from (but based on) the name or a flag of the
argument. This requires clients to maintain 2 constants for working
with arguments, if the argument contains dashes: 1 for the argument
and 1 for <code class="docutils literal notranslate"><span class="pre">dest</span></code>. With this flag you tell argparse4j to also
include the name (see below) of the argument in the result.</p>
<p>The name of an argument is determined as follows:</p>
<ul class="simple">
<li><p>Positional arguments: the name of the argument</p></li>
<li><p>Named arguments: the first long flag, or if there is no long flag,
the first flag. The prefix will be removed</p></li>
</ul>
<p>Example for positional argument:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">arguments</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">)</span>
<span class="p">.</span><span class="na">includeArgumentNamesAsKeysInResult</span><span class="p">(</span><span class="kc">true</span><span class="p">)</span>
<span class="p">.</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"foo-bar"</span><span class="p">);</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">arguments</span><span class="p">));</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo value
<span class="go">Namespace(foo_bar=value, foo-bar=value)</span>
</pre></div>
</div>
<p>Example for named argument:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">arguments</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">)</span>
<span class="p">.</span><span class="na">includeArgumentNamesAsKeysInResult</span><span class="p">(</span><span class="kc">true</span><span class="p">)</span>
<span class="p">.</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"-foo-bar"</span><span class="p">);</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">arguments</span><span class="p">));</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo -foo-bar value
<span class="go">Namespace(foo_bar=value, foo-bar=value)</span>
</pre></div>
</div>
<p>Example for named argument with long argument:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">arguments</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">)</span>
<span class="p">.</span><span class="na">includeArgumentNamesAsKeysInResult</span><span class="p">(</span><span class="kc">true</span><span class="p">)</span>
<span class="p">.</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"-f-b"</span><span class="p">,</span> <span class="s">"--foo-bar"</span><span class="p">);</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">arguments</span><span class="p">));</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo -f-b value
<span class="go">Namespace(foo_bar=value, foo-bar=value)</span>
<span class="gp">$ </span>java Demo --foo-bar value
<span class="go">Namespace(foo_bar=value, foo-bar=value)</span>
</pre></div>
</div>
<p>By default <em>includeArgumentNamesAsKeysInResult</em> is <code class="docutils literal notranslate"><span class="pre">false</span></code>, so only
<code class="docutils literal notranslate"><span class="pre">dest</span></code> of arguments is used for keys in the result.</p>
</div>
<div class="section" id="musthelptextincludemutualexclusivity">
<span id="argumentparserbuilder-musthelptextincludemutualexclusivity"></span><h3>mustHelpTextIncludeMutualExclusivity<a class="headerlink" href="#musthelptextincludemutualexclusivity" title="Permalink to this headline">¶</a></h3>
<p>The mutual exclusivity of a group is normally only shown in the usage
of a parser. By setting this option to <code class="docutils literal notranslate"><span class="pre">true</span></code>, or specifying
<code class="docutils literal notranslate"><span class="pre">DefaultSettings.VERSION_0_9_0_DEFAULT_SETTINGS</span></code> (or higher) when
creating a parser builder, a paragraph after the description and
before the arguments of a mutually-exclusive group will be added to
the help. This paragraph explains that at most 1 of the arguments of
the group may be given. Example output:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="go">MutexGroup:</span>
<span class="go"> A mutually-exclusive group.</span>
<span class="go"> At most 1 of the arguments below may be given.</span>
<span class="go"> -f First argument</span>
<span class="go"> -s Second argument</span>
</pre></div>
</div>
<p>By default <em>mustHelpTextIncludeMutualExclusivity</em> is <code class="docutils literal notranslate"><span class="pre">false</span></code>,
resulting in mutual exclusivity of a group being shown only in the
usage.</p>
</div>
<div class="section" id="nodestconversionforpositionalargs">
<span id="argumentparserbuilder-nodestconversionforpositionalargs"></span><h3>noDestConversionForPositionalArgs<a class="headerlink" href="#nodestconversionforpositionalargs" title="Permalink to this headline">¶</a></h3>
<p>Prior to 0.5.0 the destination for positional arguments was not
automatically determined from the argument name. See
<a class="reference internal" href="migration.html"><span class="doc">Migration</span></a>.
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/ArgumentParserBuilder.html#noDestConversionForPositionalArgs(boolean)"><span class="pre">ArgumentParserBuilder.noDestConversionForPositionalArgs()</span></a></code> can be used
to revert back to the pre 0.5.0 behavior. Note that you must
explicitly set a destination when you enable this option, because
otherwise the destination will be <code class="docutils literal notranslate"><span class="pre">null</span></code>:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">arguments</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">)</span>
<span class="p">.</span><span class="na">noDestConversionForPositionalArgs</span><span class="p">(</span><span class="kc">true</span><span class="p">)</span>
<span class="p">.</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"foo-bar"</span><span class="p">).</span><span class="na">dest</span><span class="p">(</span><span class="s">"explicit-dest"</span><span class="p">);</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">arguments</span><span class="p">));</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo value
<span class="go">Namespace(explicit-dest=value)</span>
</pre></div>
</div>
<p>By default <em>noDestConversionForPositionalArgs</em> is <code class="docutils literal notranslate"><span class="pre">false</span></code>, so the
names of positional arguments are automatically converted to destinations.</p>
</div>
<div class="section" id="argumentparser-description">
<span id="id2"></span><h3>ArgumentParser.description()<a class="headerlink" href="#argumentparser-description" title="Permalink to this headline">¶</a></h3>
<p>The <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#description(java.lang.String)"><span class="pre">ArgumentParser.description()</span></a></code> gives a brief description of what the
program does and how it works. In help message, the description is
displayed between command line usage string and the help messages for
the various arguments:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">()</span>
<span class="p">.</span><span class="na">description</span><span class="p">(</span><span class="s">"A foo that bars"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">printHelp</span><span class="p">();</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo
<span class="go">usage: prog [-h]</span>
<span class="go">A foo that bars</span>
<span class="go">named arguments:</span>
<span class="go"> -h, --help show this help message and exit</span>
</pre></div>
</div>
<p>By default, the description will be line-wrapped so that it fits
within the given space.</p>
</div>
<div class="section" id="argumentparser-epilog">
<span id="id3"></span><h3>ArgumentParser.epilog()<a class="headerlink" href="#argumentparser-epilog" title="Permalink to this headline">¶</a></h3>
<p>Some programs like to display additional description of the program
after the description of the arguments. Such text can be specified
using <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#epilog(java.lang.String)"><span class="pre">ArgumentParser.epilog()</span></a></code> method:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">()</span>
<span class="p">.</span><span class="na">description</span><span class="p">(</span><span class="s">"A foo that bars"</span><span class="p">)</span>
<span class="p">.</span><span class="na">epilog</span><span class="p">(</span><span class="s">"And that's how you'd foo a bar"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">printHelp</span><span class="p">();</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo
<span class="go">usage: prog [-h]</span>
<span class="go">A foo that bars</span>
<span class="go">named arguments:</span>
<span class="go"> -h, --help show this help message and exit</span>
<span class="go">And that's how you'd foo a bar</span>
</pre></div>
</div>
<p>As with the <a class="reference internal" href="#argumentparser-description"><span class="std std-ref">ArgumentParser.description()</span></a> method, text specified
in <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#epilog(java.lang.String)"><span class="pre">ArgumentParser.epilog()</span></a></code> is by default line-wrapped.</p>
</div>
<div class="section" id="argumentparser-defaulthelp">
<span id="id4"></span><h3>ArgumentParser.defaultHelp()<a class="headerlink" href="#argumentparser-defaulthelp" title="Permalink to this headline">¶</a></h3>
<p>The default value of each argument is not by default displayed in help
message. Specifying <code class="docutils literal notranslate"><span class="pre">true</span></code> to <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#defaultHelp(boolean)"><span class="pre">ArgumentParser.defaultHelp()</span></a></code> method
will display the default value of each argument in help message:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">()</span>
<span class="p">.</span><span class="na">defaultHelp</span><span class="p">(</span><span class="kc">true</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--foo"</span><span class="p">)</span>
<span class="p">.</span><span class="na">type</span><span class="p">(</span><span class="n">Integer</span><span class="p">.</span><span class="na">class</span><span class="p">)</span>
<span class="p">.</span><span class="na">setDefault</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span>
<span class="p">.</span><span class="na">help</span><span class="p">(</span><span class="s">"FOO!"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"bar"</span><span class="p">)</span>
<span class="p">.</span><span class="na">nargs</span><span class="p">(</span><span class="s">"*"</span><span class="p">)</span>
<span class="p">.</span><span class="na">setDefault</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span>
<span class="p">.</span><span class="na">help</span><span class="p">(</span><span class="s">"BAR!"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">printHelp</span><span class="p">();</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo
<span class="go">usage: prog [-h] [-f FOO] [bar [bar ...]]</span>
<span class="go">positional arguments:</span>
<span class="go"> bar BAR! (default: [1, 2, 3])</span>
<span class="go">named arguments:</span>
<span class="go"> -h, --help show this help message and exit</span>
<span class="go"> -f FOO, --foo FOO FOO! (default: 42)</span>
</pre></div>
</div>
</div>
<div class="section" id="argumentparser-usage">
<span id="id5"></span><h3>ArgumentParser.usage()<a class="headerlink" href="#argumentparser-usage" title="Permalink to this headline">¶</a></h3>
<p>By default, <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html"><span class="pre">ArgumentParser</span></a></code> calculates the usage message
from the arguments it contains:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--foo"</span><span class="p">).</span><span class="na">nargs</span><span class="p">(</span><span class="s">"?"</span><span class="p">).</span><span class="na">help</span><span class="p">(</span><span class="s">"foo help"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"bar"</span><span class="p">).</span><span class="na">nargs</span><span class="p">(</span><span class="s">"+"</span><span class="p">).</span><span class="na">help</span><span class="p">(</span><span class="s">"bar help"</span><span class="p">);</span>
<span class="n">Namespace</span> <span class="n">res</span> <span class="o">=</span> <span class="n">parser</span><span class="p">.</span><span class="na">parseArgsOrFail</span><span class="p">(</span><span class="n">args</span><span class="p">);</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo -h
<span class="go">usage: prog [-h] [--foo [FOO]] bar [bar ...]</span>
<span class="go">positional arguments:</span>
<span class="go"> bar bar help</span>
<span class="go">named arguments:</span>
<span class="go"> -h, --help show this help message and exit</span>
<span class="go"> --foo [FOO] foo help</span>
</pre></div>
</div>
<p>The default message can be overridden with the <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#usage(java.lang.String)"><span class="pre">ArgumentParser.usage()</span></a></code>
method:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">()</span>
<span class="p">.</span><span class="na">usage</span><span class="p">(</span><span class="s">"${prog} [OPTIONS]"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--foo"</span><span class="p">).</span><span class="na">nargs</span><span class="p">(</span><span class="s">"?"</span><span class="p">).</span><span class="na">help</span><span class="p">(</span><span class="s">"foo help"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"bar"</span><span class="p">).</span><span class="na">nargs</span><span class="p">(</span><span class="s">"+"</span><span class="p">).</span><span class="na">help</span><span class="p">(</span><span class="s">"bar help"</span><span class="p">);</span>
<span class="n">Namespace</span> <span class="n">res</span> <span class="o">=</span> <span class="n">parser</span><span class="p">.</span><span class="na">parseArgsOrFail</span><span class="p">(</span><span class="n">args</span><span class="p">);</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo -h
<span class="go">usage: prog [OPTIONS]</span>
<span class="go">positional arguments:</span>
<span class="go"> bar bar help</span>
<span class="go">named arguments:</span>
<span class="go"> -h, --help show this help message and exit</span>
<span class="go"> --foo [FOO] foo help</span>
</pre></div>
</div>
<p>The <code class="docutils literal notranslate"><span class="pre">${prog}</span></code> literal string in the given usage message will be
replaced with the program name
<a class="reference internal" href="#argumentparsers-newfor-prog"><span class="std std-ref">prog</span></a>.</p>
</div>
<div class="section" id="argumentparser-version">
<span id="id6"></span><h3>ArgumentParser.version()<a class="headerlink" href="#argumentparser-version" title="Permalink to this headline">¶</a></h3>
<p>The <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#version(java.lang.String)"><span class="pre">ArgumentParser.version()</span></a></code> method sets the string
describing program version. It will be displayed when
<a class="reference internal" href="#arguments-version"><span class="std std-ref">Arguments.version()</span></a> action is used.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">${prog}</span></code> literal string in the given string will be replaced
with the program name <a class="reference internal" href="#argumentparsers-newfor-prog"><span class="std std-ref">prog</span></a>.</p>
</div>
</div>
<div class="section" id="the-argumentparser-addargument-method">
<span id="argumentparser-addargument"></span><h2>The ArgumentParser.addArgument() method<a class="headerlink" href="#the-argumentparser-addargument-method" title="Permalink to this headline">¶</a></h2>
<p><code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#addArgument(java.lang.String...)"><span class="pre">ArgumentParser.addArgument()</span></a></code> method creates new <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/Argument.html"><span class="pre">Argument</span></a></code>
object and adds it to ArgumentParser’s internal memory and returns the
object to the user code. <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/Argument.html"><span class="pre">Argument</span></a></code> object defines how a
single command line argument should be parsed.
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#addArgument(java.lang.String...)"><span class="pre">ArgumentParser.addArgument()</span></a></code> method receives
<a class="reference internal" href="#argumentparser-addargument-nameorflags"><span class="std std-ref">nameOrFlags</span></a> argument, which is
either a name or a list of option strings, e.g. <code class="docutils literal notranslate"><span class="pre">"foo"</span></code> or <code class="docutils literal notranslate"><span class="pre">"-f",</span>
<span class="pre">"--foo"</span></code>. After obtained <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/Argument.html"><span class="pre">Argument</span></a></code> object, several
parameters can be specified using following methods:</p>
<ul class="simple">
<li><p><a class="reference internal" href="#argument-action"><span class="std std-ref">Argument.action()</span></a> - The basic type of action to be taken when
this argument is encountered at the command line.</p></li>
<li><p><a class="reference internal" href="#argument-nargs"><span class="std std-ref">Argument.nargs()</span></a> - The number of command line arguments that
should be consumed.</p></li>
<li><p><a class="reference internal" href="#argument-setconst"><span class="std std-ref">Argument.setConst()</span></a> - A constant value required by some
<a class="reference internal" href="#argument-action"><span class="std std-ref">Argument.action()</span></a> and <a class="reference internal" href="#argument-nargs"><span class="std std-ref">Argument.nargs()</span></a> selections.</p></li>
<li><p><a class="reference internal" href="#argument-setdefault"><span class="std std-ref">Argument.setDefault()</span></a> - The value produced if the argument is
absent from the command line.</p></li>
<li><p><a class="reference internal" href="#argument-type"><span class="std std-ref">Argument.type()</span></a> - The type to which the command line argument
should be converted.</p></li>
<li><p><a class="reference internal" href="#argument-choices"><span class="std std-ref">Argument.choices()</span></a> - A collection of the allowable values for
the argument.</p></li>
<li><p><a class="reference internal" href="#argument-required"><span class="std std-ref">Argument.required()</span></a> - Whether or not the command line option
may be omitted (named arguments only).</p></li>
<li><p><a class="reference internal" href="#argument-help"><span class="std std-ref">Argument.help()</span></a> - A brief description of what the argument
does.</p></li>
<li><p><a class="reference internal" href="#argument-metavar"><span class="std std-ref">Argument.metavar()</span></a> - A name for the argument in usage messages.</p></li>
<li><p><a class="reference internal" href="#argument-dest"><span class="std std-ref">Argument.dest()</span></a> - The name of the attribute to be added as a
result of <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#parseArgs(java.lang.String[])"><span class="pre">ArgumentParser.parseArgs()</span></a></code> method.</p></li>
</ul>
<p>The following sections describe how each of these are used.</p>
<div class="section" id="nameorflags">
<span id="argumentparser-addargument-nameorflags"></span><h3>nameOrFlags<a class="headerlink" href="#nameorflags" title="Permalink to this headline">¶</a></h3>
<p>The <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#addArgument(java.lang.String...)"><span class="pre">ArgumentParser.addArgument()</span></a></code> method must know whether a
named argument, like <code class="docutils literal notranslate"><span class="pre">-f</span></code> or <code class="docutils literal notranslate"><span class="pre">--foo</span></code>, or a positional argument,
like a list of filenames, is expected. The arguments passed to
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#addArgument(java.lang.String...)"><span class="pre">ArgumentParser.addArgument()</span></a></code> must therefore be either a series of
flags, or a simple argument name. For example, a named argument
could be created like:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"-f"</span><span class="p">,</span> <span class="s">"--foo"</span><span class="p">);</span>
</pre></div>
</div>
<p>while a positional argument could be created like:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"bar"</span><span class="p">);</span>
</pre></div>
</div>
<p>When <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#parseArgs(java.lang.String[])"><span class="pre">ArgumentParser.parseArgs()</span></a></code> is called, named arguments will
be identified by the <code class="docutils literal notranslate"><span class="pre">-</span></code> prefix (or one of
<a class="reference internal" href="#argumentparserbuilder-prefixchars"><span class="std std-ref">prefixChars</span></a> if it is
specified, and the remaining arguments will be assumed to be
positional:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"-f"</span><span class="p">,</span> <span class="s">"--foo"</span><span class="p">);</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"bar"</span><span class="p">);</span>
<span class="k">try</span> <span class="p">{</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">args</span><span class="p">));</span>
<span class="p">}</span> <span class="k">catch</span> <span class="p">(</span><span class="n">ArgumentParserException</span> <span class="n">e</span><span class="p">)</span> <span class="p">{</span>
<span class="n">parser</span><span class="p">.</span><span class="na">handleError</span><span class="p">(</span><span class="n">e</span><span class="p">);</span>
<span class="p">}</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo BAR
<span class="go">Namespace(foo=null, bar=BAR)</span>
<span class="gp">$ </span>java Demo BAR --foo FOO
<span class="go">Namespace(foo=FOO, bar=BAR)</span>
<span class="gp">$ </span>java Demo --foo FOO
<span class="go">usage: prog [-h] [-f FOO] bar</span>
<span class="go">prog: error: too few arguments</span>
</pre></div>
</div>
</div>
<div class="section" id="argument-action">
<span id="id7"></span><h3>Argument.action()<a class="headerlink" href="#argument-action" title="Permalink to this headline">¶</a></h3>
<p><code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/Argument.html"><span class="pre">Argument</span></a></code> objects associate command line arguments with
actions. These actions can do just about anything with command line
arguments associated with them, though most of the actions simply add
an attribute to the object returned by
<code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/ArgumentParser.html#parseArgs(java.lang.String[])"><span class="pre">ArgumentParser.parseArgs()</span></a></code>. The <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/inf/Argument.html#action(net.sourceforge.argparse4j.inf.ArgumentAction)"><span class="pre">Argument.action()</span></a></code> method
specifies how the command line arguments should be handled. The
supported actions follow.</p>
<div class="section" id="arguments-store">
<span id="id8"></span><h4>Arguments.store()<a class="headerlink" href="#arguments-store" title="Permalink to this headline">¶</a></h4>
<p><code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/impl/Arguments.html#store()"><span class="pre">Arguments.store()</span></a></code> just stores the argument’s value. This is
the default action. For example:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"-f"</span><span class="p">,</span> <span class="s">"--foo"</span><span class="p">);</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">args</span><span class="p">));</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo --foo <span class="m">1</span>
<span class="go">Namespace(foo=1)</span>
</pre></div>
</div>
</div>
<div class="section" id="arguments-storeconst">
<span id="id9"></span><h4>Arguments.storeConst()<a class="headerlink" href="#arguments-storeconst" title="Permalink to this headline">¶</a></h4>
<p><code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/impl/Arguments.html#storeConst()"><span class="pre">Arguments.storeConst()</span></a></code> stores the value specified by the
<a class="reference internal" href="#argument-setconst"><span class="std std-ref">Argument.setConst()</span></a>. (Note that by default const value is the
rather unhelpful <code class="docutils literal notranslate"><span class="pre">null</span></code>.) The <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/impl/Arguments.html#storeConst()"><span class="pre">Arguments.storeConst()</span></a></code> action is
most commonly used with named arguments that specify sort of
flags. For example:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--foo"</span><span class="p">).</span><span class="na">action</span><span class="p">(</span><span class="n">Arguments</span><span class="p">.</span><span class="na">storeConst</span><span class="p">()).</span><span class="na">setConst</span><span class="p">(</span><span class="mi">42</span><span class="p">);</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">args</span><span class="p">));</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo --foo
<span class="go">Namespace(foo=42)</span>
</pre></div>
</div>
</div>
<div class="section" id="arguments-storetrue-and-arguments-storefalse">
<span id="arguments-storebool"></span><h4>Arguments.storeTrue() and Arguments.storeFalse()<a class="headerlink" href="#arguments-storetrue-and-arguments-storefalse" title="Permalink to this headline">¶</a></h4>
<p><code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/impl/Arguments.html#storeTrue()"><span class="pre">Arguments.storeTrue()</span></a></code> and <code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/impl/Arguments.html#storeFalse()"><span class="pre">Arguments.storeFalse()</span></a></code> are special cases
of <a class="reference internal" href="#arguments-storeconst"><span class="std std-ref">Arguments.storeConst()</span></a> using for storing values <code class="docutils literal notranslate"><span class="pre">true</span></code> and
<code class="docutils literal notranslate"><span class="pre">false</span></code> respectively. In addition, they create default values of
<code class="docutils literal notranslate"><span class="pre">false</span></code> and <code class="docutils literal notranslate"><span class="pre">true</span></code> respectively. For example:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--foo"</span><span class="p">).</span><span class="na">action</span><span class="p">(</span><span class="n">Arguments</span><span class="p">.</span><span class="na">storeTrue</span><span class="p">());</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--bar"</span><span class="p">).</span><span class="na">action</span><span class="p">(</span><span class="n">Arguments</span><span class="p">.</span><span class="na">storeFalse</span><span class="p">());</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--baz"</span><span class="p">).</span><span class="na">action</span><span class="p">(</span><span class="n">Arguments</span><span class="p">.</span><span class="na">storeFalse</span><span class="p">());</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">args</span><span class="p">));</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo --foo --bar
<span class="go">Namespace(baz=true, foo=true, bar=false)</span>
</pre></div>
</div>
</div>
<div class="section" id="arguments-append">
<span id="arguments-appendaction"></span><h4>Arguments.append()<a class="headerlink" href="#arguments-append" title="Permalink to this headline">¶</a></h4>
<p><code class="xref docutils literal notranslate"><a class="reference external" href="apidocs/net/sourceforge/argparse4j/impl/Arguments.html#append()"><span class="pre">Arguments.append()</span></a></code> stores a list, and appends each argument value to
the list. The list is of type <code class="xref docutils literal notranslate"><span class="pre">List</span></code>. This is useful to
allow an option to be specified multiple times. For example:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="p">)</span> <span class="kd">throws</span> <span class="n">ArgumentParserException</span> <span class="p">{</span>
<span class="n">ArgumentParser</span> <span class="n">parser</span> <span class="o">=</span> <span class="n">ArgumentParsers</span><span class="p">.</span><span class="na">newFor</span><span class="p">(</span><span class="s">"prog"</span><span class="p">).</span><span class="na">build</span><span class="p">();</span>
<span class="n">parser</span><span class="p">.</span><span class="na">addArgument</span><span class="p">(</span><span class="s">"--foo"</span><span class="p">).</span><span class="na">action</span><span class="p">(</span><span class="n">Arguments</span><span class="p">.</span><span class="na">append</span><span class="p">());</span>
<span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="n">parser</span><span class="p">.</span><span class="na">parseArgs</span><span class="p">(</span><span class="n">args</span><span class="p">));</span>
<span class="p">}</span>
</pre></div>
</div>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>java Demo --foo <span class="m">1</span> --foo <span class="m">2</span>
<span class="go">Namespace(foo=[1, 2])</span>
</pre></div>
</div>
</div>
<div class="section" id="arguments-appendconst">