001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.camel.component.bean;
018
019 import java.lang.reflect.InvocationHandler;
020 import java.lang.reflect.InvocationTargetException;
021 import java.lang.reflect.Method;
022
023 import org.apache.camel.Endpoint;
024 import org.apache.camel.Exchange;
025 import org.apache.camel.ExchangePattern;
026 import org.apache.camel.Producer;
027 import org.apache.camel.RuntimeCamelException;
028 import org.apache.camel.impl.DefaultExchange;
029 import org.apache.commons.logging.Log;
030 import org.apache.commons.logging.LogFactory;
031
032 /**
033 * An {@link java.lang.reflect.InvocationHandler} which invokes a
034 * message exchange on a camel {@link Endpoint}
035 *
036 * @version $Revision: 889160 $
037 */
038 public class CamelInvocationHandler implements InvocationHandler {
039 private static final transient Log LOG = LogFactory.getLog(CamelInvocationHandler.class);
040
041 private final Endpoint endpoint;
042 private final Producer producer;
043 private final MethodInfoCache methodInfoCache;
044
045 public CamelInvocationHandler(Endpoint endpoint, Producer producer, MethodInfoCache methodInfoCache) {
046 this.endpoint = endpoint;
047 this.producer = producer;
048 this.methodInfoCache = methodInfoCache;
049 }
050
051 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
052 BeanInvocation invocation = new BeanInvocation(method, args);
053 ExchangePattern pattern = ExchangePattern.InOut;
054 MethodInfo methodInfo = methodInfoCache.getMethodInfo(method);
055 if (methodInfo != null) {
056 pattern = methodInfo.getPattern();
057 }
058 Exchange exchange = new DefaultExchange(endpoint, pattern);
059 exchange.getIn().setBody(invocation);
060
061 // process the exchange
062 if (LOG.isTraceEnabled()) {
063 LOG.trace("Proxied method call " + method.getName() + " invoking producer: " + producer);
064 }
065 producer.process(exchange);
066
067 // check if we had an exception
068 Throwable fault = exchange.getException();
069 if (fault != null) {
070 if (fault instanceof RuntimeCamelException) {
071 // if the inner cause is a runtime exception we can throw it directly
072 if (fault.getCause() instanceof RuntimeException) {
073 throw (RuntimeException) ((RuntimeCamelException) fault).getCause();
074 }
075 throw (RuntimeCamelException) fault;
076 }
077 throw new InvocationTargetException(fault);
078 }
079
080 // do not return a reply if the method is VOID or the MEP is not OUT capable
081 Class<?> to = method.getReturnType();
082 if (to == Void.TYPE || !pattern.isOutCapable()) {
083 return null;
084 }
085
086 // only convert if there is a body
087 if (!exchange.hasOut() || exchange.getOut().getBody() == null) {
088 // there is no body so return null
089 return null;
090 }
091
092 // use type converter so we can convert output in the desired type defined by the method
093 // and let it be mandatory so we know wont return null if we cant convert it to the defined type
094 Object answer = exchange.getOut().getMandatoryBody(to);
095 if (LOG.isTraceEnabled()) {
096 LOG.trace("Proxied method call " + method.getName() + " returning: " + answer);
097 }
098 return answer;
099 }
100 }
101