initial commit client for rpc java tutorial

Author: Ann Witbrock

java/RPCClient.java

@@ -0,0 +1,74 @@
+import java.io.IOException;
+import com.rabbitmq.client.ConnectionFactory;
+import com.rabbitmq.client.Connection;
+import com.rabbitmq.client.Channel;
+import com.rabbitmq.client.QueueingConsumer;
+import com.rabbitmq.client.AMQP.BasicProperties;
+import java.util.UUID;
+
+public class RPCClient {
+  
+  private static final String RPC_QUEUE_NAME = "rpc_queue";
+  
+  static class FibonacciClient {
+    private Channel channel;
+    private String queue;
+    
+    public FibonacciClient(Channel chann, String queueName){
+          channel = chann;
+          queue = queueName;
+    }
+    
+    public String call(String message)
+                        throws java.io.IOException,
+                               java.lang.InterruptedException {
+      String replyQueueName = channel.queueDeclare().getQueue();      
+      String corrId = UUID.randomUUID().toString();
+      BasicProperties props = new BasicProperties();
+      props.setReplyTo(replyQueueName);
+      props.setCorrelationId(corrId);
+      
+      QueueingConsumer consumer = new QueueingConsumer(channel);
+      channel.basicConsume(replyQueueName, true, consumer);
+
+      channel.basicPublish("", queue, props, message.getBytes());
+      
+      String response = "";
+
+      while (!validResponse(response)){
+      	 QueueingConsumer.Delivery delivery = consumer.nextDelivery();
+      	 response = new String(delivery.getBody());        	         	         
+      }
+      return response;  
+    }
+    
+    private Boolean validResponse(String response){
+    	    return (response.length() > 0);
+    }
+  }
+  
+  private static Connection defaultConnection()throws java.io.IOException{
+    ConnectionFactory factory = new ConnectionFactory();
+    factory.setHost("localhost");
+    return factory.newConnection();
+  }
+  
+  public static void main(String[] argv) 
+                    throws java.io.IOException,
+                           java.lang.InterruptedException {
+
+    Connection connection = defaultConnection();
+    Channel channel = connection.createChannel();
+      
+    RPCClient.FibonacciClient rpc = new RPCClient.FibonacciClient(channel, RPC_QUEUE_NAME);
+    
+    System.out.println(" [x] Requesting fib(30)");    
+    String response = rpc.call("30"); 
+    
+    System.out.println(" [.] Got '" + response + "'");
+    
+    channel.close();
+    connection.close();
+  }  
+}
+