Backend: distributed cache and messaging (Redis, RabbitMQ, Kafka, SQS, Pub/Sub)

docs/demos/backend/src/main/java/com/codenameone/developerguide/backend/messaging/Checkout.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2012, Codename One and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Codename One designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Codename One through http://www.codenameone.com/ if you
+ * need additional information or have any questions.
+ */
+package com.codenameone.developerguide.backend.messaging;
+
+import com.codename1.backend.DataSource;
+import com.codename1.backend.annotations.Component;
+import com.codename1.backend.annotations.Transactional;
+import com.codename1.backend.messaging.MessageTemplate;
+import com.codenameone.developerguide.backend.orders.Order;
+
+import java.io.IOException;
+
+// tag::backend-messaging-send[]
+@Component
+public class Checkout {
+    private final DataSource db;
+    private final MessageTemplate messages;
+
+    public Checkout(DataSource db, MessageTemplate messages) {
+        this.db = db;
+        this.messages = messages;
+    }
+
+    @Transactional
+    public void place(Order order) throws IOException {
+        db.execute("INSERT INTO orders (id, customer) VALUES (?, ?)",
+                new Object[] {Long.valueOf(order.id), order.customer});
+        // Written to the outbox in this transaction, sent once it commits.
+        messages.send("orders.placed", order.customer, order);
+    }
+}
+// end::backend-messaging-send[]

docs/demos/backend/src/main/java/com/codenameone/developerguide/backend/messaging/OrderLookup.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2012, Codename One and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Codename One designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Codename One through http://www.codenameone.com/ if you
+ * need additional information or have any questions.
+ */
+package com.codenameone.developerguide.backend.messaging;
+
+import com.codename1.backend.annotations.CacheEvict;
+import com.codename1.backend.annotations.Cacheable;
+import com.codename1.backend.annotations.Component;
+import com.codenameone.developerguide.backend.orders.Order;
+
+// tag::backend-cache[]
+@Component
+public class OrderLookup {
+    @Cacheable(value = "orders", key = "#p0")
+    public Order find(long id) {
+        return load(id);
+    }
+
+    @CacheEvict(value = "orders", key = "#p0.id")
+    public void update(Order order) {
+        // write the change; the next find() reads it again
+    }
+// end::backend-cache[]
+
+    private Order load(long id) {
+        Order o = new Order();
+        o.id = id;
+        return o;
+    }
+}

docs/demos/backend/src/main/java/com/codenameone/developerguide/backend/messaging/Shipping.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2012, Codename One and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Codename One designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Codename One through http://www.codenameone.com/ if you
+ * need additional information or have any questions.
+ */
+package com.codenameone.developerguide.backend.messaging;
+
+import com.codename1.backend.annotations.Component;
+import com.codename1.backend.annotations.KafkaListener;
+import com.codename1.backend.annotations.MessageListener;
+import com.codename1.backend.messaging.Message;
+import com.codenameone.developerguide.backend.orders.Order;
+
+// tag::backend-messaging-listen[]
+@Component
+public class Shipping {
+    @MessageListener(value = "orders.placed", group = "shipping", concurrency = 4)
+    public void placed(Order order) {
+        // runs once per message; throwing has it delivered again later
+    }
+
+    @MessageListener(value = "orders.placed.dlq", group = "support")
+    public void gaveUp(Message message) {
+        String why = message.getHeader(Message.ERROR);
+        // the order that failed every attempt, and the last exception
+    }
+}
+// end::backend-messaging-listen[]
+
+// tag::backend-messaging-spring[]
+@Component
+class Invoicing {
+    @KafkaListener(topics = "orders.placed", groupId = "invoicing")
+    public void placed(Order order) {
+        // the same listener, written as a Spring Kafka application writes it
+    }
+}
+// end::backend-messaging-spring[]

docs/demos/backend/src/main/resources/application.properties

@@ -5,3 +5,11 @@
 cn1.datasource.url=${DATABASE_URL}
 cn1.server.port=8080
 # end::backend-config-base[]
+
+# tag::backend-scale-out[]
+# One Redis for the cache, sessions, rate limits and scheduler locks...
+cn1.kv.url=${REDIS_URL}
+cn1.session.store=kv
+# ...and a broker for messages.
+cn1.messaging.url=kafka://kafka-1:9092,kafka-2:9092
+# end::backend-scale-out[]