001/*
002 * Copyright 2002-2017 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.lang.Nullable;
028import org.springframework.util.ClassUtils;
029
030/**
031 * Simple method invoker bean: just invoking a target method, not expecting a result
032 * to expose to the container (in contrast to {@link MethodInvokingFactoryBean}).
033 *
034 * <p>This invoker supports any kind of target method. A static method may be specified
035 * by setting the {@link #setTargetMethod targetMethod} property to a String representing
036 * the static method name, with {@link #setTargetClass targetClass} specifying the Class
037 * that the static method is defined on. Alternatively, a target instance method may be
038 * specified, by setting the {@link #setTargetObject targetObject} property as the target
039 * object, and the {@link #setTargetMethod targetMethod} property as the name of the
040 * method to call on that target object. Arguments for the method invocation may be
041 * specified by setting the {@link #setArguments arguments} property.
042 *
043 * <p>This class depends on {@link #afterPropertiesSet()} being called once
044 * all properties have been set, as per the InitializingBean contract.
045 *
046 * <p>An example (in an XML based bean factory definition) of a bean definition
047 * which uses this class to call a static initialization method:
048 *
049 * <pre class="code">
050 * &lt;bean id="myObject" class="org.springframework.beans.factory.config.MethodInvokingBean">
051 *   &lt;property name="staticMethod" value="com.whatever.MyClass.init"/>
052 * &lt;/bean></pre>
053 *
054 * <p>An example of calling an instance method to start some server bean:
055 *
056 * <pre class="code">
057 * &lt;bean id="myStarter" class="org.springframework.beans.factory.config.MethodInvokingBean">
058 *   &lt;property name="targetObject" ref="myServer"/>
059 *   &lt;property name="targetMethod" value="start"/>
060 * &lt;/bean></pre>
061 *
062 * @author Juergen Hoeller
063 * @since 4.0.3
064 * @see MethodInvokingFactoryBean
065 * @see org.springframework.util.MethodInvoker
066 */
067public class MethodInvokingBean extends ArgumentConvertingMethodInvoker
068                implements BeanClassLoaderAware, BeanFactoryAware, InitializingBean {
069
070        @Nullable
071        private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();
072
073        @Nullable
074        private ConfigurableBeanFactory beanFactory;
075
076
077        @Override
078        public void setBeanClassLoader(ClassLoader classLoader) {
079                this.beanClassLoader = classLoader;
080        }
081
082        @Override
083        protected Class<?> resolveClassName(String className) throws ClassNotFoundException {
084                return ClassUtils.forName(className, this.beanClassLoader);
085        }
086
087        @Override
088        public void setBeanFactory(BeanFactory beanFactory) {
089                if (beanFactory instanceof ConfigurableBeanFactory) {
090                        this.beanFactory = (ConfigurableBeanFactory) beanFactory;
091                }
092        }
093
094        /**
095         * Obtain the TypeConverter from the BeanFactory that this bean runs in,
096         * if possible.
097         * @see ConfigurableBeanFactory#getTypeConverter()
098         */
099        @Override
100        protected TypeConverter getDefaultTypeConverter() {
101                if (this.beanFactory != null) {
102                        return this.beanFactory.getTypeConverter();
103                }
104                else {
105                        return super.getDefaultTypeConverter();
106                }
107        }
108
109
110        @Override
111        public void afterPropertiesSet() throws Exception {
112                prepare();
113                invokeWithTargetException();
114        }
115
116        /**
117         * Perform the invocation and convert InvocationTargetException
118         * into the underlying target exception.
119         */
120        @Nullable
121        protected Object invokeWithTargetException() throws Exception {
122                try {
123                        return invoke();
124                }
125                catch (InvocationTargetException ex) {
126                        if (ex.getTargetException() instanceof Exception) {
127                                throw (Exception) ex.getTargetException();
128                        }
129                        if (ex.getTargetException() instanceof Error) {
130                                throw (Error) ex.getTargetException();
131                        }
132                        throw ex;
133                }
134        }
135
136}