BeanPostProcessor for proxying TaskExecutor instances to allow delegation to an error handler when async execution throws errors.

Relates to INT-440

org.springframework.integration/src/main/java/org/springframework/integration/executor/ErrorHandlingExecutorBeanPostProcessor.java

@@ -0,0 +1,61 @@
+/*
+ * 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.executor;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.aop.framework.ProxyFactory;
+import org.springframework.aop.support.DefaultPointcutAdvisor;
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.core.task.TaskExecutor;
+import org.springframework.integration.util.ErrorHandler;
+
+/**
+ * 
+ * @author Jonas Partner
+ *
+ */
+public class ErrorHandlingExecutorBeanPostProcessor implements BeanPostProcessor {
+
+	private final RunnableProxyingMethodInterceptor runnableProxyingInterceptor;
+
+	private volatile List<String> beanNamesToExclude = new ArrayList<String>();
+
+	public ErrorHandlingExecutorBeanPostProcessor(ErrorHandler errorHandler) {
+		this.runnableProxyingInterceptor = new RunnableProxyingMethodInterceptor(errorHandler);
+	}
+
+	public void setTaskExecutorBeanNameExclusions(List<String> beanNamesToExclude) {
+		this.beanNamesToExclude = beanNamesToExclude;
+	}
+
+	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
+		if (bean instanceof TaskExecutor && !beanNamesToExclude.contains(beanName)) {
+			ProxyFactory proxyFactory = new ProxyFactory(bean);
+			proxyFactory.addAdvisor(new DefaultPointcutAdvisor(this.runnableProxyingInterceptor));
+			return proxyFactory.getProxy();
+		}
+		return bean;
+	}
+
+	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
+		return bean;
+	}
+
+}

org.springframework.integration/src/main/java/org/springframework/integration/executor/RunnableProxyingMethodInterceptor.java

@@ -0,0 +1,69 @@
+/*
+ * 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.executor;
+
+import org.aopalliance.intercept.MethodInterceptor;
+import org.aopalliance.intercept.MethodInvocation;
+import org.springframework.aop.framework.ProxyFactory;
+import org.springframework.core.task.TaskExecutor;
+import org.springframework.integration.util.ErrorHandler;
+
+/**
+ * Used tby {@link ErrorHandlingExecutorBeanPostProcessor} to Proxy
+ * {@link TaskExecutor} instances. This allow the wrapping of {@link Runnable}
+ * instances in order to handle catch errors thrown and delegate handling to an
+ * instance of {@link ErrorHandler}
+ * @author Jonas Partner
+ * 
+ */
+public class RunnableProxyingMethodInterceptor implements MethodInterceptor {
+
+	private final ErrorHandler errorHandler;
+
+	public RunnableProxyingMethodInterceptor(ErrorHandler errorHandler) {
+		this.errorHandler = errorHandler;
+	}
+
+	public Object invoke(MethodInvocation invocation) throws Throwable {
+		Runnable runnable = (Runnable) invocation.getArguments()[0];
+		ProxyFactory factory = new ProxyFactory(runnable);
+		factory.addAdvice(new ErrorHandlingAdvice(errorHandler));
+		invocation.getArguments()[0] = factory.getProxy();
+		return invocation.proceed();
+	}
+
+	private static class ErrorHandlingAdvice implements MethodInterceptor {
+
+		private final ErrorHandler errorHandler;
+
+		public ErrorHandlingAdvice(ErrorHandler errorHandler) {
+			this.errorHandler = errorHandler;
+		}
+
+		public Object invoke(MethodInvocation invocation) throws Throwable {
+			try {
+				invocation.proceed();
+			}
+			catch (Throwable t) {
+				errorHandler.handle(t);
+			}
+			return null;
+		}
+
+	}
+
+}