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 */
017package org.apache.camel.builder;
018
019import org.apache.camel.Exchange;
020import org.apache.camel.Expression;
021import org.apache.camel.Predicate;
022import org.apache.camel.language.simple.SimpleLanguage;
023import org.apache.camel.util.ObjectHelper;
024
025/**
026 * Creates an {@link org.apache.camel.language.Simple} language builder.
027 * <p/>
028 * This builder is available in the Java DSL from the {@link RouteBuilder} which means that using
029 * simple language for {@link Expression}s or {@link Predicate}s is very easy with the help of this builder.
030 *
031 * @version 
032 */
033public class SimpleBuilder implements Predicate, Expression {
034
035    private final String text;
036    private Class<?> resultType;
037    // cache the expression/predicate
038    private volatile Expression expression;
039    private volatile Predicate predicate;
040
041    public SimpleBuilder(String text) {
042        this.text = text;
043    }
044
045    public static SimpleBuilder simple(String text) {
046        return new SimpleBuilder(text);
047    }
048
049    public static SimpleBuilder simple(String text, Class<?> resultType) {
050        SimpleBuilder answer = simple(text);
051        answer.setResultType(resultType);
052        return answer;
053    }
054
055    public String getText() {
056        return text;
057    }
058
059    public Class<?> getResultType() {
060        return resultType;
061    }
062
063    public void setResultType(Class<?> resultType) {
064        this.resultType = resultType;
065    }
066
067    public SimpleBuilder resultType(Class<?> resultType) {
068        setResultType(resultType);
069        return this;
070    }
071
072    public boolean matches(Exchange exchange) {
073        if (predicate == null) {
074            predicate = createPredicate(exchange);
075        }
076        return predicate.matches(exchange);
077    }
078
079    public <T> T evaluate(Exchange exchange, Class<T> type) {
080        if (expression == null) {
081            expression = createExpression(exchange);
082        }
083        return expression.evaluate(exchange, type);
084    }
085
086    private Predicate createPredicate(Exchange exchange) {
087        SimpleLanguage simple = (SimpleLanguage) exchange.getContext().resolveLanguage("simple");
088        // resolve property placeholders
089        try {
090            String resolve = exchange.getContext().resolvePropertyPlaceholders(text);
091            return simple.createPredicate(resolve);
092        } catch (Exception e) {
093            throw ObjectHelper.wrapCamelExecutionException(exchange, e);
094        }
095    }
096
097    private Expression createExpression(Exchange exchange) {
098        SimpleLanguage simple = (SimpleLanguage) exchange.getContext().resolveLanguage("simple");
099        // resolve property placeholders
100        try {
101            String resolve = exchange.getContext().resolvePropertyPlaceholders(text);
102            return simple.createExpression(resolve, resultType);
103        } catch (Exception e) {
104            throw ObjectHelper.wrapCamelExecutionException(exchange, e);
105        }
106    }
107
108    public String toString() {
109        return "Simple: " + text;
110    }
111}