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.Expression;
020 import org.apache.camel.IsSingleton;
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://camel.apache.org/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://camel.apache.org/registry.html>registry</a>
032 * then the method is invoked to evaluate the expression using the
033 * <a href="http://camel.apache.org/bean-integration.html">bean integration</a> to bind the
034 * {@link org.apache.camel.Exchange} to the method arguments.
035 * <p/>
036 * As of Camel 1.5 the bean language also supports invoking a provided bean by
037 * its classname or the bean itself.
038 *
039 * @version $Revision: 752893 $
040 */
041 public class BeanLanguage implements Language, IsSingleton {
042
043 /**
044 * Creates the expression based on the string syntax.
045 *
046 * @param expression the string syntax <tt>beanRef.methodName</tt> where methodName can be omitted
047 * @return the expression
048 */
049 public static Expression bean(String expression) {
050 BeanLanguage language = new BeanLanguage();
051 return language.createExpression(expression);
052 }
053
054 /**
055 * Creates the expression for invoking the bean type.
056 *
057 * @param beanType the bean type to invoke
058 * @param method optional name of method to invoke for instance to avoid ambiguity
059 * @return the expression
060 */
061 @SuppressWarnings("unchecked")
062 public static Expression bean(Class beanType, String method) {
063 Object bean = ObjectHelper.newInstance(beanType);
064 return bean(bean, method);
065 }
066
067 /**
068 * Creates the expression for invoking the bean type.
069 *
070 * @param bean the bean to invoke
071 * @param method optional name of method to invoke for instance to avoid ambiguity
072 * @return the expression
073 */
074 public static Expression bean(Object bean, String method) {
075 BeanLanguage language = new BeanLanguage();
076 return language.createExpression(bean, method);
077 }
078
079 public Predicate createPredicate(String expression) {
080 return PredicateBuilder.toPredicate(createExpression(expression));
081 }
082
083 public Expression createExpression(String expression) {
084 ObjectHelper.notNull(expression, "expression");
085
086 String beanName = expression;
087 String method = null;
088
089 // we support both the .method name and the ?method= syntax
090 // as the ?method= syntax is very common for the bean component
091 int idx = expression.lastIndexOf('.');
092 if (idx > 0) {
093 beanName = expression.substring(0, idx);
094 method = expression.substring(idx + 1);
095 } else if (expression.contains("?method=")) {
096 beanName = ObjectHelper.before(expression, "?");
097 method = ObjectHelper.after(expression, "?method=");
098 }
099
100 return new BeanExpression(beanName, method);
101 }
102
103 public Expression createExpression(Object bean, String method) {
104 ObjectHelper.notNull(bean, "bean");
105 return new BeanExpression(bean, method);
106 }
107
108 public boolean isSingleton() {
109 return true;
110 }
111 }