INT-3883: UDP: destination and socket expressions

JIRA: https://jira.spring.io/browse/INT-3883

UDP Outbound Channel Adapter is able to use given UDP Inbound Adapters
server socket (outgoing packets will have source port same as incoming
packets destination port).

* Introduce `destinationExpression` instead of hard-coded `host/port` logic in the `DatagramPacketMessageMapper`
* Make `UnicastSendingMessageHandler.destinationExpression` mutually exclusive with `host/port` pair
* Move `socketExpression` to the setter as it is absolutely different option from the `destination`
* Make `UnicastSendingMessageHandler` expressions logic based on the `requestMessage`

INT-3883 Code review fixes.

Further polishing

Polishing according PR comments

Rework the String socket address logic just to the expected `URI` style.
Accept `2016` for changed classes.

spring-integration-ip/src/test/java/org/springframework/integration/ip/udp/DatagramPacketMulticastSendingHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.integration.ip.udp;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
 
 import java.net.DatagramPacket;
 import java.net.DatagramSocket;
@@ -34,6 +35,7 @@ import org.apache.commons.logging.LogFactory;
 import org.junit.Rule;
 import org.junit.Test;
 
+import org.springframework.beans.factory.BeanFactory;
 import org.springframework.integration.ip.IpHeaders;
 import org.springframework.integration.support.MessageBuilder;
 import org.springframework.messaging.Message;
@@ -98,7 +100,9 @@ public class DatagramPacketMulticastSendingHandlerTests {
 		executor.execute(catcher);
 		assertTrue(listening.await(10000, TimeUnit.MILLISECONDS));
 		MulticastSendingMessageHandler handler = new MulticastSendingMessageHandler(multicastAddress, testPort);
+		handler.setBeanFactory(mock(BeanFactory.class));
 		handler.setLocalAddress(this.multicastRule.getNic());
+		handler.afterPropertiesSet();
 		handler.handleMessage(MessageBuilder.withPayload(payload).build());
 		assertTrue(received.await(10000, TimeUnit.MILLISECONDS));
 		handler.stop();
@@ -176,6 +180,7 @@ public class DatagramPacketMulticastSendingHandlerTests {
 			new MulticastSendingMessageHandler(multicastAddress, testPort, true, true, "localhost", 0, 10000);
 		handler.setLocalAddress(this.multicastRule.getNic());
 		handler.setMinAcksForSuccess(2);
+		handler.setBeanFactory(mock(BeanFactory.class));
 		handler.afterPropertiesSet();
 		handler.start();
 		waitAckListening(handler);

spring-integration-ip/src/test/java/org/springframework/integration/ip/udp/DatagramPacketSendingHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -38,6 +38,7 @@ import org.springframework.messaging.Message;
 /**
  * @author Mark Fisher
  * @author Gary Russell
+ * @author Marcin Pilaczynski
  * @since 2.0
  */
 public class DatagramPacketSendingHandlerTests {

spring-integration-ip/src/test/java/org/springframework/integration/ip/udp/UdpChannelAdapterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -39,6 +39,8 @@ import org.junit.Rule;
 import org.junit.Test;
 
 import org.springframework.beans.factory.BeanFactory;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.support.ClassPathXmlApplicationContext;
 import org.springframework.integration.channel.DirectChannel;
 import org.springframework.integration.channel.QueueChannel;
 import org.springframework.integration.handler.ServiceActivatingHandler;
@@ -53,6 +55,7 @@ import org.springframework.messaging.SubscribableChannel;
  *
  * @author Gary Russell
  * @author Artem Bilan
+ * @author Marcin Pilaczynski
  * @since 2.0
  *
  */
@@ -326,12 +329,30 @@ public class UdpChannelAdapterTests {
 		adapter.stop();
 	}
 
+	@Test
+	public void testSocketExpression() throws Exception {
+		ConfigurableApplicationContext context =
+				new ClassPathXmlApplicationContext("testIp-socket-expression-context.xml", getClass());
+		UnicastReceivingChannelAdapter adapter = context.getBean(UnicastReceivingChannelAdapter.class);
+		SocketTestUtils.waitListening(adapter);
+		int receiverServerPort = adapter.getPort();
+		DatagramPacket packet = new DatagramPacket("foo".getBytes(), 3);
+		packet.setSocketAddress(new InetSocketAddress("localhost", receiverServerPort));
+		DatagramSocket socket = new DatagramSocket();
+		socket.send(packet);
+		socket.receive(packet);
+		assertEquals("FOO", new String(packet.getData()));
+		assertEquals(receiverServerPort, packet.getPort());
+		context.close();
+	}
+
 	private class FailingService {
+
 		@SuppressWarnings("unused")
 		public String serviceMethod(byte[] bytes) {
 			throw new RuntimeException("Failed");
 		}
+
 	}
 
-
 }

spring-integration-ip/src/test/java/org/springframework/integration/ip/udp/testIp-socket-expression-context.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+	   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	   xmlns:int="http://www.springframework.org/schema/integration"
+	   xmlns:int-ip="http://www.springframework.org/schema/integration/ip"
+	   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
+		http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration.xsd
+		http://www.springframework.org/schema/integration/ip http://www.springframework.org/schema/integration/ip/spring-integration-ip.xsd">
+
+	<int-ip:udp-inbound-channel-adapter id="inbound" port="0" channel="in" />
+
+	<int:channel id="in" />
+
+	<int:transformer expression="new String(payload).toUpperCase()" input-channel="in" output-channel="out"/>
+
+	<int:channel id="out" />
+
+	<int-ip:udp-outbound-channel-adapter socket-expression="@inbound.socket"
+										 destination-expression="'udp://localhost:' + headers['ip_packetAddress'].port"
+										 channel="out" />
+
+</beans>