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.language.bean;
018
019 import org.apache.camel.Exchange;
020 import org.apache.camel.ExchangePattern;
021 import org.apache.camel.Expression;
022 import org.apache.camel.Predicate;
023 import org.apache.camel.component.bean.BeanHolder;
024 import org.apache.camel.component.bean.BeanProcessor;
025 import org.apache.camel.component.bean.ConstantBeanHolder;
026 import org.apache.camel.component.bean.RegistryBean;
027 import org.apache.camel.util.ObjectHelper;
028
029 /**
030 * Evaluates an expression using a bean method invocation
031 *
032 * @version $Revision: 820990 $
033 */
034 public class BeanExpression implements Expression, Predicate {
035 private String beanName;
036 private String method;
037 private Object bean;
038
039 public BeanExpression(Object bean, String method) {
040 this.bean = bean;
041 this.method = method;
042 }
043
044 public BeanExpression(String beanName, String method) {
045 this.beanName = beanName;
046 this.method = method;
047 }
048
049 @Override
050 public String toString() {
051 return "BeanExpression[bean:" + (bean == null ? beanName : bean) + " method: " + method + "]";
052 }
053
054 public Object evaluate(Exchange exchange) {
055 // either use registry lookup or a constant bean
056 BeanHolder holder;
057 if (bean == null) {
058 holder = new RegistryBean(exchange.getContext(), beanName);
059 } else {
060 holder = new ConstantBeanHolder(bean, exchange.getContext());
061 }
062
063 BeanProcessor processor = new BeanProcessor(holder);
064 if (method != null) {
065 processor.setMethod(method);
066 }
067 try {
068 Exchange newExchange = exchange.copy();
069 // The BeanExperession always has a result regardless of the ExchangePattern,
070 // so I add a checker here to make sure we can get the result.
071 if (!newExchange.getPattern().isOutCapable()) {
072 newExchange.setPattern(ExchangePattern.InOut);
073 }
074 processor.process(newExchange);
075 return newExchange.getOut().getBody();
076 } catch (Exception e) {
077 throw new RuntimeBeanExpressionException(exchange, beanName, method, e);
078 }
079 }
080
081 public <T> T evaluate(Exchange exchange, Class<T> type) {
082 Object result = evaluate(exchange);
083 return exchange.getContext().getTypeConverter().convertTo(type, result);
084 }
085
086 public boolean matches(Exchange exchange) {
087 Object value = evaluate(exchange);
088 return ObjectHelper.evaluateValuePredicate(value);
089 }
090
091 }