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 import 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 */
033 public 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 Expression exp = simple.createExpression(resolve);
103 if (resultType != null) {
104 exp = ExpressionBuilder.convertToExpression(exp, resultType);
105 }
106 return exp;
107 } catch (Exception e) {
108 throw ObjectHelper.wrapCamelExecutionException(exchange, e);
109 }
110 }
111
112 public String toString() {
113 return "Simple: " + text;
114 }
115 }