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.Expression;
021    import org.apache.camel.Predicate;
022    import org.apache.camel.builder.PredicateBuilder;
023    import org.apache.camel.spi.Language;
024    import org.apache.camel.util.ObjectHelper;
025    
026    /**
027     * A <a href="http://activemq.apache.org/camel/bean-language.html">bean language</a>
028     * which uses a simple text notation to invoke methods on beans to evaluate predicates or expressions
029     * <p/>
030     * The notation is essentially <code>beanName.methodName</code> which is then invoked using the
031     * beanName to lookup in the <a href="http://activemq.apache.org/camel/registry.html>registry</a>
032     * then the method is invoked to evaluate the expression using the
033     * <a href="http://activemq.apache.org/camel/bean-integration.html">bean integration</a> to bind the
034     * {@link Exchange} to the method arguments.
035     *
036     * @version $Revision: 47012 $
037     */
038    public class BeanLanguage implements Language {
039    
040        public static Expression bean(String expression) {
041            BeanLanguage language = new BeanLanguage();
042            return language.createExpression(expression);
043        }
044    
045        public Predicate<Exchange> createPredicate(String expression) {
046            return PredicateBuilder.toPredicate(createExpression(expression));
047        }
048    
049        public Expression<Exchange> createExpression(String expression) {
050            ObjectHelper.notNull(expression, "expression");
051    
052            int idx = expression.lastIndexOf('.');
053            String beanName = expression;
054            String method = null;
055            if (idx > 0) {
056                beanName = expression.substring(0, idx);
057                method = expression.substring(idx + 1);
058            }
059            return new BeanExpression(beanName, method);
060        }
061    
062    }