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.ognl;
018    
019    import java.util.HashMap;
020    import java.util.Map;
021    
022    import ognl.Ognl;
023    import ognl.OgnlContext;
024    import ognl.OgnlException;
025    
026    import org.apache.camel.Exchange;
027    import org.apache.camel.impl.ExpressionSupport;
028    import org.apache.camel.language.ExpressionEvaluationException;
029    import org.apache.camel.language.IllegalSyntaxException;
030    
031    /**
032     * @version $Revision: $
033     */
034    public class OgnlExpression extends ExpressionSupport<Exchange> {
035    
036        private final String expressionString;
037        private final Class<?> type;
038        private Object expression;
039    
040        public OgnlExpression(OgnlLanguage language, String expressionString, Class<?> type) {
041            this.expressionString = expressionString;
042            this.type = type;
043            try {
044                this.expression = Ognl.parseExpression(expressionString);
045            } catch (OgnlException e) {
046                throw new IllegalSyntaxException(language, expressionString);
047            }
048        }
049    
050        public static OgnlExpression ognl(String expression) {
051            return new OgnlExpression(new OgnlLanguage(), expression, Object.class);
052        }
053    
054        public Object evaluate(Exchange exchange) {
055            // TODO we could use caching here but then we'd have possible
056            // concurrency issues
057            // so lets assume that the provider caches
058            Map values = new HashMap();
059            populateContext(values, exchange);
060            OgnlContext oglContext = new OgnlContext();
061            try {
062                return Ognl.getValue(expression, oglContext, new RootObject(exchange));
063            } catch (OgnlException e) {
064                throw new ExpressionEvaluationException(this, exchange, e);
065            }
066        }
067    
068        protected void populateContext(Map map, Exchange exchange) {
069            map.put("exchange", exchange);
070            map.put("in", exchange.getIn());
071            map.put("out", exchange.getOut());
072        }
073    
074        protected String assertionFailureMessage(Exchange exchange) {
075            return expressionString;
076        }
077    }