Added MapBasedChannelResolver. Routers that want to provide an extra level of indirection may be configured with a map of channel names to channel instances rather than relying on the default BeanFactoryChannelResolver that matches the name against bean names directly.

org.springframework.integration/src/test/java/org/springframework/integration/channel/MapBasedChannelResolverTests.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2002-2008 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.channel;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Test;
+
+/**
+ * @author Mark Fisher
+ */
+public class MapBasedChannelResolverTests {
+
+	@Test
+	public void mapContainsChannel() {
+		MessageChannel testChannel = new QueueChannel();
+		Map<String, MessageChannel> channelMap = new HashMap<String, MessageChannel>();
+		channelMap.put("testChannel", testChannel);
+		MapBasedChannelResolver resolver = new MapBasedChannelResolver();
+		resolver.setChannelMap(channelMap);
+		MessageChannel result = resolver.resolveChannelName("testChannel");
+		assertNotNull(result);
+		assertEquals(testChannel, result);
+	}
+
+	@Test
+	public void mapDoesNotContainChannel() {
+		MessageChannel testChannel = new QueueChannel();
+		Map<String, MessageChannel> channelMap = new HashMap<String, MessageChannel>();
+		channelMap.put("testChannel", testChannel);
+		MapBasedChannelResolver resolver = new MapBasedChannelResolver();
+		resolver.setChannelMap(channelMap);
+		MessageChannel result = resolver.resolveChannelName("noSuchChannel");
+		assertNull(result);
+	}
+
+	@Test
+	public void emptyMap() {
+		Map<String, MessageChannel> channelMap = new HashMap<String, MessageChannel>();
+		MapBasedChannelResolver resolver = new MapBasedChannelResolver();
+		resolver.setChannelMap(channelMap);
+		MessageChannel result = resolver.resolveChannelName("testChannel");
+		assertNull(result);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void nullMapRejected() {
+		MapBasedChannelResolver resolver = new MapBasedChannelResolver();
+		resolver.setChannelMap(null);
+	}
+
+}