Add javadoc to quick start examples.

example/src/main/java/org/apache/rocketmq/example/quickstart/Consumer.java

@@ -25,15 +25,39 @@ import org.apache.rocketmq.client.exception.MQClientException;
 import org.apache.rocketmq.common.consumer.ConsumeFromWhere;
 import org.apache.rocketmq.common.message.MessageExt;
 
+/**
+ * This example shows how to subscribe and consume messages using providing {@link DefaultMQPushConsumer}.
+ */
 public class Consumer {
 
     public static void main(String[] args) throws InterruptedException, MQClientException {
+
+        /*
+         * Instantiate with specified consumer group name.
+         */
         DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("please_rename_unique_group_name_4");
 
+        /*
+         * Specify name server addresses.
+         * <p/>
+         *
+         * Alternatively, you may specify name server addresses via exporting environmental variable: NAMESRV_ADDR
+         */
+        consumer.setNamesrvAddr("name-server1-ip:9876;name-server2-ip:9876");
+
+        /*
+         * Specify where to start in case the specified consumer group is a brand new one.
+         */
         consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);
 
+        /*
+         * Subscribe one more more topics to consume.
+         */
         consumer.subscribe("TopicTest", "*");
 
+        /*
+         *  Register callback to execute on arrival of messages fetched from brokers.
+         */
         consumer.registerMessageListener(new MessageListenerConcurrently() {
 
             @Override
@@ -44,7 +68,11 @@ public class Consumer {
             }
         });
 
+        /*
+         *  Launch the consumer instance.
+         */
         consumer.start();
+
         System.out.printf("Consumer Started.%n");
     }
 }

example/src/main/java/org/apache/rocketmq/example/quickstart/Producer.java

@@ -18,36 +18,60 @@ package org.apache.rocketmq.example.quickstart;
 
 import org.apache.rocketmq.client.exception.MQClientException;
 import org.apache.rocketmq.client.producer.DefaultMQProducer;
-import org.apache.rocketmq.client.producer.LocalTransactionExecuter;
-import org.apache.rocketmq.client.producer.LocalTransactionState;
 import org.apache.rocketmq.client.producer.SendResult;
 import org.apache.rocketmq.common.message.Message;
 import org.apache.rocketmq.remoting.common.RemotingHelper;
 
+/**
+ * This class demonstrates how to send messages to brokers using provided {@link DefaultMQProducer}.
+ */
 public class Producer {
     public static void main(String[] args) throws MQClientException, InterruptedException {
+
+        /*
+         * Instantiate with a producer group name.
+         */
         DefaultMQProducer producer = new DefaultMQProducer("please_rename_unique_group_name");
+
+        /*
+         * Specify name server addresses.
+         * <p/>
+         *
+         * Alternatively, you may specify name server addresses via exporting environmental variable: NAMESRV_ADDR
+         */
+        producer.setNamesrvAddr("name-server1-ip:9876;name-server2-ip:9876");
+
+        /*
+         * Launch the instance.
+         */
         producer.start();
 
         for (int i = 0; i < 1000; i++) {
             try {
-                Message msg = new Message("TopicTest",
-                    "TagA",
-                    ("Hello RocketMQ " + i).getBytes(RemotingHelper.DEFAULT_CHARSET)
+
+                /*
+                 * Create a message instance, specifying topic, tag and message body.
+                 */
+                Message msg = new Message("TopicTest" /* Topic */,
+                    "TagA" /* Tag */,
+                    ("Hello RocketMQ " + i).getBytes(RemotingHelper.DEFAULT_CHARSET) /* Message body */
                 );
+
+                /*
+                 * Call send message to deliver message to one of brokers.
+                 */
                 SendResult sendResult = producer.send(msg);
-                LocalTransactionExecuter tranExecuter = new LocalTransactionExecuter() {
-                    @Override
-                    public LocalTransactionState executeLocalTransactionBranch(Message msg, Object arg) {
-                        return null;
-                    }
-                };
+
                 System.out.printf("%s%n", sendResult);
             } catch (Exception e) {
                 e.printStackTrace();
                 Thread.sleep(1000);
             }
         }
+
+        /*
+         * Shut down once the producer instance is not longer in use.
+         */
         producer.shutdown();
     }
 }