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.InvocationTargetException;
020    import java.lang.reflect.Method;
021    
022    import org.apache.camel.CamelContext;
023    import org.apache.camel.Exchange;
024    import org.apache.camel.Message;
025    import org.apache.camel.Processor;
026    import org.apache.camel.impl.ServiceSupport;
027    import org.apache.camel.util.CamelContextHelper;
028    import org.apache.camel.util.ObjectHelper;
029    import org.apache.camel.util.ServiceHelper;
030    import org.apache.commons.logging.Log;
031    import org.apache.commons.logging.LogFactory;
032    import static org.apache.camel.util.ObjectHelper.isNullOrBlank;
033    
034    /**
035     * A {@link Processor} which converts the inbound exchange to a method
036     * invocation on a POJO
037     *
038     * @version $Revision: 36321 $
039     */
040    public class BeanProcessor extends ServiceSupport implements Processor {
041        public static final String METHOD_NAME = "org.apache.camel.MethodName";
042        private static final Log LOG = LogFactory.getLog(BeanProcessor.class);
043    
044        private Method methodObject;
045        private String method;
046        private BeanHolder beanHolder;
047    
048        public BeanProcessor(Object pojo, BeanInfo beanInfo) {
049            this(new ConstantBeanHolder(pojo, beanInfo));
050        }
051    
052        public BeanProcessor(Object pojo, CamelContext camelContext, ParameterMappingStrategy parameterMappingStrategy) {
053            this(pojo, new BeanInfo(camelContext, pojo.getClass(), parameterMappingStrategy));
054        }
055    
056        public BeanProcessor(Object pojo, CamelContext camelContext) {
057            this(pojo, camelContext, BeanInfo.createParameterMappingStrategy(camelContext));
058        }
059    
060        public BeanProcessor(BeanHolder beanHolder) {
061            this.beanHolder = beanHolder;
062        }
063    
064        @Override
065        public String toString() {
066            String description = methodObject != null ? " " + methodObject : "";
067            return "BeanProcessor[" + beanHolder + description + "]";
068        }
069    
070        public void process(Exchange exchange) throws Exception {
071            if (LOG.isDebugEnabled()) {
072                LOG.debug(">>>> invoking method for: " + exchange);
073            }
074    
075            Object bean = beanHolder.getBean();
076            exchange.setProperty("CamelBean", bean);
077    
078            Processor processor = getProcessor();
079            BeanInfo beanInfo = beanHolder.getBeanInfo();
080    
081            // do we have a custom adapter for this POJO to a Processor
082            if (processor != null) {
083                processor.process(exchange);
084                return;
085            }
086            Message in = exchange.getIn();
087            BeanInvocation beanInvoke = in.getBody(BeanInvocation.class);
088            if (beanInvoke != null) {
089                beanInvoke.invoke(bean, exchange);
090                return;
091            }
092    
093            boolean isExplicitMethod = false;
094            String prevMethod = null;
095            MethodInvocation invocation;
096            if (methodObject != null) {
097                invocation = beanInfo.createInvocation(methodObject, bean, exchange);
098            } else {
099                // we just override the bean's invocation method name here
100                if (ObjectHelper.isNotNullAndNonEmpty(method)) {
101                    prevMethod = in.getHeader(METHOD_NAME, String.class);
102                    in.setHeader(METHOD_NAME, method);
103                    isExplicitMethod = true;
104                }
105                invocation = beanInfo.createInvocation(bean, exchange);
106            }
107            if (invocation == null) {
108                throw new IllegalStateException("No method invocation could be created, "
109                                                + "no maching method could be found on: " + bean);
110            }
111            try {
112                Object value = invocation.proceed();
113                if (value != null) {
114                    exchange.getOut().setBody(value);
115                }
116            } catch (InvocationTargetException e) {
117                // lets unwrap the exception
118                Throwable cause = e.getCause();
119                if (cause instanceof Exception) {
120                    throw (Exception) cause;
121                } else {
122                    // do not handle errors!
123                    throw e;
124                }
125            } catch (Exception e) {
126                throw e;
127            } catch (Throwable throwable) {
128                throw new Exception(throwable);
129            } finally {
130                if (isExplicitMethod) {
131                    in.setHeader(METHOD_NAME, prevMethod);
132                }
133            }
134        }
135    
136        protected Processor getProcessor() {
137            return beanHolder.getProcessor();
138        }
139    
140        // Properties
141        // -----------------------------------------------------------------------
142    
143        public Method getMethodObject() {
144            return methodObject;
145        }
146    
147        public void setMethodObject(Method methodObject) {
148            this.methodObject = methodObject;
149        }
150    
151        public String getMethod() {
152            return method;
153        }
154    
155        /**
156         * Sets the method name to use
157         */
158        public void setMethod(String method) {
159            this.method = method;
160        }
161    
162        /**
163         * Kept around for backwards compatibility, please use {@link #setMethod(String)}
164         * in future instead.
165         *
166         * @deprecated
167         * @see #setMethod(String)
168         * @param method
169         */
170        public void setMethodName(String method) {
171            setMethod(method);
172        }
173    
174        // Implementation methods
175        //-------------------------------------------------------------------------
176        protected void doStart() throws Exception {
177            ServiceHelper.startService(getProcessor());
178        }
179    
180        protected void doStop() throws Exception {
181            ServiceHelper.stopService(getProcessor());
182        }
183    }