OPEN - issue INT-567: Add round-robin dispatching strategy

http://jira.springframework.org/browse/INT-567

Fixed issue with concurrent failures and removed triedHandlers

org.springframework.integration/src/test/java/org/springframework/integration/dispatcher/RoundRobinDispatcherConcurrentTests.java

@@ -1,6 +1,7 @@
 package org.springframework.integration.dispatcher;
 
 import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -13,6 +14,7 @@ import org.mockito.runners.MockitoJUnit44Runner;
 import org.springframework.integration.core.Message;
 import org.springframework.integration.message.MessageDeliveryException;
 import org.springframework.integration.message.MessageHandler;
+import org.springframework.integration.message.MessageRejectedException;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
 
 @RunWith(MockitoJUnit44Runner.class)
@@ -20,7 +22,7 @@ public class RoundRobinDispatcherConcurrentTests {
 
 	private static final int TOTAL_EXECUTIONS = 40;
 
-	private AbstractWinningHandlerDispatcher dispatcher = new RoundRobinDispatcher();
+	private AbstractHandleOnceDispatcher dispatcher = new RoundRobinDispatcher();
 
 	private ThreadPoolTaskExecutor scheduler = new ThreadPoolTaskExecutor();
 
@@ -76,9 +78,13 @@ public class RoundRobinDispatcherConcurrentTests {
 		start.countDown();
 		allDone.await();
 		assertFalse("not all messages were accepted", failed.get());
+		verify(handler1, times(TOTAL_EXECUTIONS / 4)).handleMessage(message);
+		verify(handler2, times(TOTAL_EXECUTIONS / 4)).handleMessage(message);
+		verify(handler3, times(TOTAL_EXECUTIONS / 4)).handleMessage(message);
+		verify(handler4, times(TOTAL_EXECUTIONS / 4)).handleMessage(message);
 	}
 
-	@Test(timeout=2000)
+	@Test(timeout = 2000)
 	public void unlockOnFailure() throws Exception {
 		// dispatcher has no subscribers (shouldn't lead to deadlock)
 		final CountDownLatch start = new CountDownLatch(1);
@@ -97,7 +103,7 @@ public class RoundRobinDispatcherConcurrentTests {
 					fail("this shouldn't happen");
 				}
 				catch (MessageDeliveryException e) {
-					//expected
+					// expected
 				}
 				allDone.countDown();
 			}
@@ -108,4 +114,39 @@ public class RoundRobinDispatcherConcurrentTests {
 		start.countDown();
 		allDone.await();
 	}
+
+	@Test
+	public void noHandlerSkipUnderConcurrentFailure() throws Exception {
+		dispatcher.addHandler(handler1);
+		dispatcher.addHandler(handler2);
+		doThrow(new MessageRejectedException(message)).when(handler1).handleMessage(message);
+		final CountDownLatch start = new CountDownLatch(1);
+		final CountDownLatch allDone = new CountDownLatch(TOTAL_EXECUTIONS);
+		final Message<?> message = this.message;
+		final AtomicBoolean failed = new AtomicBoolean(false);
+		Runnable messageSenderTask = new Runnable() {
+			public void run() {
+				try {
+					start.await();
+				}
+				catch (InterruptedException e) {
+					Thread.currentThread().interrupt();
+				}
+				if (!dispatcher.dispatch(message)) {
+					failed.set(true);
+				}
+				else {
+					allDone.countDown();
+				}
+			}
+		};
+		for (int i = 0; i < TOTAL_EXECUTIONS; i++) {
+			scheduler.execute(messageSenderTask);
+		}
+		start.countDown();
+		allDone.await();
+		assertFalse("not all messages were accepted", failed.get());
+		verify(handler1, times(TOTAL_EXECUTIONS/2)).handleMessage(message);
+		verify(handler2, times(TOTAL_EXECUTIONS)).handleMessage(message);
+	}
 }

org.springframework.integration/src/test/java/org/springframework/integration/dispatcher/RoundRobinDispatcherTests.java

@@ -35,7 +35,7 @@ import org.springframework.integration.message.MessageHandler;
 @RunWith(MockitoJUnit44Runner.class)
 public class RoundRobinDispatcherTests {
 
-	private AbstractWinningHandlerDispatcher dispatcher = new RoundRobinDispatcher();
+	private AbstractHandleOnceDispatcher dispatcher = new RoundRobinDispatcher();
 
 	@Mock
 	private MessageHandler handler;