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.spi.Language;
023 import org.apache.camel.util.ExpressionToPredicateAdapter;
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
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 public static Expression bean(Class<?> beanType, String method) {
062 Object bean = ObjectHelper.newInstance(beanType);
063 return bean(bean, method);
064 }
065
066 /**
067 * Creates the expression for invoking the bean type.
068 *
069 * @param bean the bean to invoke
070 * @param method optional name of method to invoke for instance to avoid ambiguity
071 * @return the expression
072 */
073 public static Expression bean(Object bean, String method) {
074 BeanLanguage language = new BeanLanguage();
075 return language.createExpression(bean, method);
076 }
077
078 public Predicate createPredicate(String expression) {
079 return ExpressionToPredicateAdapter.toPredicate(createExpression(expression));
080 }
081
082 public Expression createExpression(String expression) {
083 ObjectHelper.notNull(expression, "expression");
084
085 String beanName = expression;
086 String method = null;
087
088 // we support both the .method name and the ?method= syntax
089 // as the ?method= syntax is very common for the bean component
090 int idx = expression.lastIndexOf('.');
091 if (idx > 0) {
092 beanName = expression.substring(0, idx);
093 method = expression.substring(idx + 1);
094 } else if (expression.contains("?method=")) {
095 beanName = ObjectHelper.before(expression, "?");
096 method = ObjectHelper.after(expression, "?method=");
097 }
098
099 return new BeanExpression(beanName, method);
100 }
101
102 public Expression createExpression(Object bean, String method) {
103 ObjectHelper.notNull(bean, "bean");
104 return new BeanExpression(bean, method);
105 }
106
107 public boolean isSingleton() {
108 return true;
109 }
110 }