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.language;
018    
019    import java.io.InputStream;
020    
021    import org.apache.camel.CamelExchangeException;
022    import org.apache.camel.Exchange;
023    import org.apache.camel.Expression;
024    import org.apache.camel.impl.DefaultProducer;
025    import org.apache.camel.util.IOHelper;
026    import org.apache.camel.util.ObjectHelper;
027    
028    /**
029     * Language producer.
030     *
031     * @version 
032     */
033    public class LanguageProducer extends DefaultProducer {
034    
035        public LanguageProducer(LanguageEndpoint endpoint) {
036            super(endpoint);
037        }
038    
039        public void process(Exchange exchange) throws Exception {
040            // is there a custom expression in the header?
041            Expression exp = exchange.getIn().getHeader(Exchange.LANGUAGE_SCRIPT, Expression.class);
042            if (exp == null) {
043                String script = exchange.getIn().getHeader(Exchange.LANGUAGE_SCRIPT, String.class);
044                if (script != null) {
045                    // the script may be a file: so resolve it before using
046                    script = getEndpoint().resolveScript(script);
047                    exp = getEndpoint().getLanguage().createExpression(script);
048                }
049            }
050            // if not fallback to use expression from endpoint
051            if (exp == null) {
052                exp = getEndpoint().getExpression();
053            }
054    
055            // fallback and use resource uri from endpoint
056            if (exp == null) {
057                if (getEndpoint().getResourceUri() != null) {
058                    // load the resource
059                    String script;
060                    InputStream is = getEndpoint().getResourceAsInputStream();
061                    try {
062                        script = getEndpoint().getCamelContext().getTypeConverter().convertTo(String.class, exchange, is);
063                    } finally {
064                        IOHelper.close(is);
065                    }
066                    // create the expression from the script
067                    exp = getEndpoint().getLanguage().createExpression(script);
068                    // expression was resolved from resource
069                    getEndpoint().setContentResolvedFromResource(true);
070                    // if we cache then set this as expression on endpoint so we don't re-create it again
071                    if (getEndpoint().isContentCache()) {
072                        getEndpoint().setExpression(exp);
073                    }
074                } else {
075                    // no script to execute
076                    throw new CamelExchangeException("No script to evaluate", exchange);
077                }
078            }
079    
080            ObjectHelper.notNull(exp, "expression");
081    
082            Object result = exp.evaluate(exchange, Object.class);
083            log.debug("Evaluated expression as: {} with: {}", result, exchange);
084    
085            // set message body if transform is enabled
086            if (getEndpoint().isTransform()) {
087                if (exchange.hasOut()) {
088                    exchange.getOut().setBody(result);
089                } else {
090                    exchange.getIn().setBody(result);
091                }
092            }
093        }
094    
095        @Override
096        public LanguageEndpoint getEndpoint() {
097            return (LanguageEndpoint) super.getEndpoint();
098        }
099    }