INT-736, added DelayerUsageTest showing how to apply delayer

org.springframework.integration/src/test/java/org/springframework/integration/config/xml/DelayerUsageTests-context.xml

@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans:beans xmlns="http://www.springframework.org/schema/integration"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xmlns:beans="http://www.springframework.org/schema/beans"
+	xsi:schemaLocation="http://www.springframework.org/schema/beans
+			http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
+			http://www.springframework.org/schema/integration
+			http://www.springframework.org/schema/integration/spring-integration-1.0.xsd">
+
+	<channel id="inputA"/>
+
+	<channel id="outputA">
+		<queue />
+	</channel>
+
+	<delayer id="delayerWithDefaultScheduler"
+			 input-channel="inputA"
+			 output-channel="outputA"
+			 default-delay="1000"
+			 delay-header-name="foo"
+			 order="99"
+			 send-timeout="1000"
+			 wait-for-tasks-to-complete-on-shutdown="true"/>
+
+	<channel id="inputB"/>
+	<channel id="outputB"/>
+	<channel id="outputB1">
+		<queue />
+	</channel>
+ 
+	<delayer id="delayerWithCustomScheduler"
+			 input-channel="inputB"
+			 output-channel="outputB"
+			 default-delay="1000"
+			 send-timeout="20000"
+			 scheduler="multiThreadScheduler"/> 
+
+	<beans:bean id="multiThreadScheduler" class="org.springframework.scheduling.concurrent.ScheduledExecutorFactoryBean">
+		<beans:property name="poolSize" value="5"/>
+	</beans:bean>
+	
+	<service-activator input-channel="outputB" output-channel="outputB1" method="processMessage" ref="sampleHandler"/>
+	
+	<beans:bean id="sampleHandler" class="org.springframework.integration.config.xml.DelayerUsageTests$SampleService"/>
+ 
+</beans:beans>

org.springframework.integration/src/test/java/org/springframework/integration/config/xml/DelayerUsageTests.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2002-2009 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.integration.config.xml;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.integration.channel.PollableChannel;
+import org.springframework.integration.core.Message;
+import org.springframework.integration.core.MessageChannel;
+import org.springframework.integration.message.MessageBuilder;
+import org.springframework.integration.message.StringMessage;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+/**
+ * @author Oleg Zhurakousky
+ * @since 1.0.3
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration
+public class DelayerUsageTests {
+	
+	@Autowired @Qualifier("inputA")
+	private MessageChannel inputA;
+	@Autowired @Qualifier("outputA")
+	private PollableChannel outputA;
+	
+	@Autowired @Qualifier("inputB")
+	private MessageChannel inputB;
+	@Autowired @Qualifier("outputB1")
+	private PollableChannel outputB1;
+	@Autowired
+	private SampleService sampleHandler;
+	
+	@Test
+	public void testDelayWithDefaultScheduler(){
+		long start = System.currentTimeMillis();
+		inputA.send(new StringMessage("Hello"));
+		Message<String> msg = (Message<String>) outputA.receive();
+		assertTrue((System.currentTimeMillis() - start) >= 1000);
+	}
+	@Test
+	public void testDelayWithDefaultSchedulerCustomDelayHeader(){
+		MessageBuilder builder = MessageBuilder.withPayload("Hello");
+		// set custom delay header
+		builder.setHeader("foo", 2000);
+		long start = System.currentTimeMillis();
+		inputA.send(builder.build());		
+		Message<String> msg = (Message<String>) outputA.receive();
+		assertTrue((System.currentTimeMillis() - start) >= 2000);
+	}
+	@Test
+	public void testDelayWithCustomScheduler(){	
+		long start = System.currentTimeMillis();
+		inputB.send(new StringMessage("1")); 
+		inputB.send(new StringMessage("2"));
+		inputB.send(new StringMessage("3"));
+		inputB.send(new StringMessage("4"));
+		inputB.send(new StringMessage("5"));
+		inputB.send(new StringMessage("6"));
+		inputB.send(new StringMessage("7"));
+		Message<String> msg = (Message<String>) outputB1.receive();
+		msg = (Message<String>) outputB1.receive();
+		msg = (Message<String>) outputB1.receive();
+		msg = (Message<String>) outputB1.receive();
+		msg = (Message<String>) outputB1.receive();
+		msg = (Message<String>) outputB1.receive();
+		msg = (Message<String>) outputB1.receive();
+	
+		// must execute under 3 seconds, since threadPool is set too 5.
+		// first batch is 5 concurrent invocations on SA, then 2 more
+		// elapsed time for the whole execution should be a bit over 2 seconds depending on the hardware
+		assertTrue(((System.currentTimeMillis() - start) >= 1000) && ((System.currentTimeMillis() - start) < 3000));
+	}
+	
+	
+	public static class SampleService{
+		public String processMessage(String message) throws Exception {
+			Thread.sleep(500);
+			return message;
+		}
+	}
+}