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.builder;
018    
019    import org.apache.camel.Exchange;
020    import org.apache.camel.Expression;
021    import org.apache.camel.Predicate;
022    import org.apache.camel.language.simple.SimpleLanguage;
023    
024    /**
025     * Creates an {@link org.apache.camel.language.Simple} language builder.
026     * <p/>
027     * This builder is available in the Java DSL from the {@link RouteBuilder} which means that using
028     * simple language for {@link Expression}s or {@link Predicate}s is very easy with the help of this builder.
029     *
030     * @version 
031     */
032    public class SimpleBuilder implements Predicate, Expression {
033    
034        private final String text;
035        private Class<?> resultType;
036        // cache the expression/predicate
037        private volatile Expression expression;
038        private volatile Predicate predicate;
039    
040        public SimpleBuilder(String text) {
041            this.text = text;
042        }
043    
044        public static SimpleBuilder simple(String text) {
045            return new SimpleBuilder(text);
046        }
047    
048        public static SimpleBuilder simple(String text, Class<?> resultType) {
049            SimpleBuilder answer = simple(text);
050            answer.setResultType(resultType);
051            return answer;
052        }
053    
054        public String getText() {
055            return text;
056        }
057    
058        public Class<?> getResultType() {
059            return resultType;
060        }
061    
062        public void setResultType(Class<?> resultType) {
063            this.resultType = resultType;
064        }
065    
066        public SimpleBuilder resultType(Class<?> resultType) {
067            setResultType(resultType);
068            return this;
069        }
070    
071        public boolean matches(Exchange exchange) {
072            if (predicate == null) {
073                predicate = exchange.getContext().resolveLanguage("simple").createPredicate(text);
074            }
075            return predicate.matches(exchange);
076        }
077    
078        public <T> T evaluate(Exchange exchange, Class<T> type) {
079            if (expression == null) {
080                expression = createExpression(exchange);
081            }
082            return expression.evaluate(exchange, type);
083        }
084    
085        private Expression createExpression(Exchange exchange) {
086            SimpleLanguage simple = (SimpleLanguage) exchange.getContext().resolveLanguage("simple");
087            if (resultType != null) {
088                simple.setResultType(resultType);
089            }
090            return simple.createExpression(text);
091        }
092    
093        public String toString() {
094            return "Simple: " + text;
095        }
096    }