Added MethodInvokingSelector.

org.springframework.integration/src/main/java/org/springframework/integration/filter/MethodInvokingSelector.java

@@ -0,0 +1,56 @@
+/*
+ * 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.filter;
+
+import java.lang.reflect.Method;
+
+import org.springframework.integration.message.Message;
+import org.springframework.integration.message.MessageMappingMethodInvoker;
+import org.springframework.integration.message.selector.MessageSelector;
+import org.springframework.util.Assert;
+
+/**
+ * A method-invoking implementation of {@link MessageSelector}.
+ * 
+ * @author Mark Fisher
+ */
+public class MethodInvokingSelector implements MessageSelector {
+
+	private final MessageMappingMethodInvoker invoker;
+
+
+	public MethodInvokingSelector(Object object, Method method) {
+		this.invoker = new MessageMappingMethodInvoker(object, method);
+		Class<?> returnType = method.getReturnType();
+		Assert.isTrue(boolean.class.isAssignableFrom(returnType)
+				|| Boolean.class.isAssignableFrom(returnType),
+				"MethodInvokingSelector method must return a boolean result.");
+	}
+
+	public MethodInvokingSelector(Object object, String methodName) {
+		this.invoker = new MessageMappingMethodInvoker(object, methodName);
+	}
+
+
+	public boolean accept(Message<?> message) {
+		Object result = this.invoker.invokeMethod(message);
+		Assert.notNull(result, "result must not be null");
+		Assert.isAssignable(Boolean.class, result.getClass(), "a boolean result is required");
+		return (Boolean) result;
+	}
+
+}

org.springframework.integration/src/test/java/org/springframework/integration/filter/MethodInvokingSelectorTests.java

@@ -0,0 +1,106 @@
+/*
+ * 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.filter;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.lang.reflect.Method;
+
+import org.junit.Test;
+
+import org.springframework.integration.message.GenericMessage;
+import org.springframework.integration.message.Message;
+import org.springframework.integration.message.StringMessage;
+
+/**
+ * @author Mark Fisher
+ */
+public class MethodInvokingSelectorTests {
+
+	@Test
+	public void acceptedWithMethodName() {
+		MethodInvokingSelector selector = new MethodInvokingSelector(new TestBean(), "acceptString");
+		assertTrue(selector.accept(new StringMessage("should accept")));
+	}
+
+	@Test
+	public void acceptedWithMethodReference() throws Exception {
+		TestBean testBean = new TestBean();
+		Method method = testBean.getClass().getMethod("acceptString", new Class[] { Message.class });
+		MethodInvokingSelector selector = new MethodInvokingSelector(testBean, method);
+		assertTrue(selector.accept(new StringMessage("should accept")));
+	}
+
+	@Test
+	public void rejectedWithMethodName() {
+		MethodInvokingSelector selector = new MethodInvokingSelector(new TestBean(), "acceptString");
+		assertFalse(selector.accept(new GenericMessage<Integer>(99)));
+	}
+
+	@Test
+	public void rejectedWithMethodReference() throws Exception {
+		TestBean testBean = new TestBean();
+		Method method = testBean.getClass().getMethod("acceptString", new Class[] { Message.class });
+		MethodInvokingSelector selector = new MethodInvokingSelector(testBean, method);
+		assertFalse(selector.accept(new GenericMessage<Integer>(99)));
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void noArgMethodWithMethodName() {
+		MethodInvokingSelector selector = new MethodInvokingSelector(new TestBean(), "noArgs");
+		selector.accept(new StringMessage("test"));
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void noArgMethodWithMethodReference() throws Exception {
+		TestBean testBean = new TestBean();
+		Method method = testBean.getClass().getMethod("noArgs", new Class[] {});
+		MethodInvokingSelector selector = new MethodInvokingSelector(testBean, method);
+		selector.accept(new StringMessage("test"));
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void voidReturningMethodWithMethodName() {
+		MethodInvokingSelector selector = new MethodInvokingSelector(new TestBean(), "returnVoid");
+		selector.accept(new StringMessage("test"));
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void voidReturningMethodWithMethodReference() throws Exception {
+		TestBean testBean = new TestBean();
+		Method method = testBean.getClass().getMethod("returnVoid", new Class[] { Message.class });
+		MethodInvokingSelector selector = new MethodInvokingSelector(testBean, method);
+		selector.accept(new StringMessage("test"));
+	}
+
+
+	private static class TestBean {
+
+		public boolean acceptString(Message<?> message) {
+			return (message.getPayload() instanceof String);
+		}
+
+		public void returnVoid(Message<?> message) {
+		}
+
+		public boolean noArgs() {
+			return true;
+		}
+	}
+
+}