001/*
002 * Copyright 2002-2014 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.beans.factory.config;
018
019import java.lang.reflect.InvocationTargetException;
020
021import org.springframework.beans.TypeConverter;
022import org.springframework.beans.factory.BeanClassLoaderAware;
023import org.springframework.beans.factory.BeanFactory;
024import org.springframework.beans.factory.BeanFactoryAware;
025import org.springframework.beans.factory.InitializingBean;
026import org.springframework.beans.support.ArgumentConvertingMethodInvoker;
027import org.springframework.util.ClassUtils;
028
029/**
030 * Simple method invoker bean: just invoking a target method, not expecting a result
031 * to expose to the container (in contrast to {@link MethodInvokingFactoryBean}).
032 *
033 * <p>This invoker supports any kind of target method. A static method may be specified
034 * by setting the {@link #setTargetMethod targetMethod} property to a String representing
035 * the static method name, with {@link #setTargetClass targetClass} specifying the Class
036 * that the static method is defined on. Alternatively, a target instance method may be
037 * specified, by setting the {@link #setTargetObject targetObject} property as the target
038 * object, and the {@link #setTargetMethod targetMethod} property as the name of the
039 * method to call on that target object. Arguments for the method invocation may be
040 * specified by setting the {@link #setArguments arguments} property.
041 *
042 * <p>This class depends on {@link #afterPropertiesSet()} being called once
043 * all properties have been set, as per the InitializingBean contract.
044 *
045 * <p>An example (in an XML based bean factory definition) of a bean definition
046 * which uses this class to call a static initialization method:
047 *
048 * <pre class="code">
049 * &lt;bean id="myObject" class="org.springframework.beans.factory.config.MethodInvokingBean">
050 *   &lt;property name="staticMethod" value="com.whatever.MyClass.init"/>
051 * &lt;/bean></pre>
052 *
053 * <p>An example of calling an instance method to start some server bean:
054 *
055 * <pre class="code">
056 * &lt;bean id="myStarter" class="org.springframework.beans.factory.config.MethodInvokingBean">
057 *   &lt;property name="targetObject" ref="myServer"/>
058 *   &lt;property name="targetMethod" value="start"/>
059 * &lt;/bean></pre>
060 *
061 * @author Juergen Hoeller
062 * @since 4.0.3
063 * @see MethodInvokingFactoryBean
064 * @see org.springframework.util.MethodInvoker
065 */
066public class MethodInvokingBean extends ArgumentConvertingMethodInvoker
067                implements BeanClassLoaderAware, BeanFactoryAware, InitializingBean {
068
069        private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();
070
071        private ConfigurableBeanFactory beanFactory;
072
073
074        @Override
075        public void setBeanClassLoader(ClassLoader classLoader) {
076                this.beanClassLoader = classLoader;
077        }
078
079        @Override
080        protected Class<?> resolveClassName(String className) throws ClassNotFoundException {
081                return ClassUtils.forName(className, this.beanClassLoader);
082        }
083
084        @Override
085        public void setBeanFactory(BeanFactory beanFactory) {
086                if (beanFactory instanceof ConfigurableBeanFactory) {
087                        this.beanFactory = (ConfigurableBeanFactory) beanFactory;
088                }
089        }
090
091        /**
092         * Obtain the TypeConverter from the BeanFactory that this bean runs in,
093         * if possible.
094         * @see ConfigurableBeanFactory#getTypeConverter()
095         */
096        @Override
097        protected TypeConverter getDefaultTypeConverter() {
098                if (this.beanFactory != null) {
099                        return this.beanFactory.getTypeConverter();
100                }
101                else {
102                        return super.getDefaultTypeConverter();
103                }
104        }
105
106
107        @Override
108        public void afterPropertiesSet() throws Exception {
109                prepare();
110                invokeWithTargetException();
111        }
112
113        /**
114         * Perform the invocation and convert InvocationTargetException
115         * into the underlying target exception.
116         */
117        protected Object invokeWithTargetException() throws Exception {
118                try {
119                        return invoke();
120                }
121                catch (InvocationTargetException ex) {
122                        if (ex.getTargetException() instanceof Exception) {
123                                throw (Exception) ex.getTargetException();
124                        }
125                        if (ex.getTargetException() instanceof Error) {
126                                throw (Error) ex.getTargetException();
127                        }
128                        throw ex;
129                }
130        }
131
132}