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.language.bean;
018
019import org.apache.camel.Expression;
020import org.apache.camel.IsSingleton;
021import org.apache.camel.Predicate;
022import org.apache.camel.spi.Language;
023import org.apache.camel.util.ExpressionToPredicateAdapter;
024import org.apache.camel.util.ObjectHelper;
025import org.apache.camel.util.StringHelper;
026
027/**
028 * A <a href="http://camel.apache.org/bean-language.html">bean language</a>
029 * which uses a simple text notation to invoke methods on beans to evaluate predicates or expressions
030 * <p/>
031 * The notation is essentially <code>beanName.methodName</code> which is then invoked using the
032 * beanName to lookup in the <a href="http://camel.apache.org/registry.html>registry</a>
033 * then the method is invoked to evaluate the expression using the
034 * <a href="http://camel.apache.org/bean-integration.html">bean integration</a> to bind the
035 * {@link org.apache.camel.Exchange} to the method arguments.
036 * <p/>
037 * As of Camel 1.5 the bean language also supports invoking a provided bean by
038 * its classname or the bean itself.
039 *
040 * @version 
041 */
042public class BeanLanguage implements Language, IsSingleton {
043
044    /**
045     * Creates the expression based on the string syntax.
046     *
047     * @param expression the string syntax <tt>beanRef.methodName</tt> where methodName can be omitted
048     * @return the expression
049     */
050    public static Expression bean(String expression) {
051        BeanLanguage language = new BeanLanguage();
052        return language.createExpression(expression);
053    }
054
055    /**
056     * Creates the expression for invoking the bean type.
057     *
058     * @param beanType  the bean type to invoke
059     * @param method optional name of method to invoke for instance to avoid ambiguity
060     * @return the expression
061     */
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 ExpressionToPredicateAdapter.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        if (expression.contains("?method=")) {
092            beanName = StringHelper.before(expression, "?");
093            method = StringHelper.after(expression, "?method=");
094        } else {
095            //first check case :: because of my.own.Bean::method
096            int doubleColonIndex = expression.indexOf("::");
097            //need to check that not inside params
098            int beginOfParameterDeclaration = expression.indexOf("(");
099            if (doubleColonIndex > 0 && (expression.indexOf("(") < 0 || doubleColonIndex < beginOfParameterDeclaration)) {
100                beanName = expression.substring(0, doubleColonIndex);
101                method = expression.substring(doubleColonIndex + 2);
102            } else {
103                int idx = expression.indexOf('.');
104                if (idx > 0) {
105                    beanName = expression.substring(0, idx);
106                    method = expression.substring(idx + 1);
107                }
108            }
109        }
110
111        return new BeanExpression(beanName, method);
112    }
113
114    public Expression createExpression(Object bean, String method) {
115        ObjectHelper.notNull(bean, "bean");
116        return new BeanExpression(bean, method);
117    }
118
119    public boolean isSingleton() {
120        return true;
121    }
122}