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: 751450 $
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        protected String assertionFailureMessage(Exchange exchange) {
055            return "bean: " + beanName + " method: " + method;
056        }
057    
058        public Object evaluate(Exchange exchange) {
059            // either use registry lookup or a constant bean
060            BeanHolder holder;
061            if (bean == null) {
062                holder = new RegistryBean(exchange.getContext(), beanName);
063            } else {
064                holder = new ConstantBeanHolder(bean, exchange.getContext());
065            }
066    
067            BeanProcessor processor = new BeanProcessor(holder);
068            if (method != null) {
069                processor.setMethod(method);
070            }
071            try {
072                Exchange newExchange = exchange.copy();
073                // The BeanExperession always has a result regardless of the ExchangePattern,
074                // so I add a checker here to make sure we can get the result.
075                if (!newExchange.getPattern().isOutCapable()) {
076                    newExchange.setPattern(ExchangePattern.InOut);
077                }
078                processor.process(newExchange);
079                return newExchange.getOut(true).getBody();
080            } catch (Exception e) {
081                throw new RuntimeBeanExpressionException(exchange, beanName, method, e);
082            }
083        }
084    
085        public <T> T evaluate(Exchange exchange, Class<T> type) {
086            Object result = evaluate(exchange);
087            return exchange.getContext().getTypeConverter().convertTo(type, result);
088        }
089    
090        public boolean matches(Exchange exchange) {
091            Object value = evaluate(exchange);
092            return ObjectHelper.evaluateValuePredicate(value);
093        }
094    
095        public void assertMatches(String text, Exchange exchange) throws AssertionError {
096        }
097    }