/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.factory.config;

import java.lang.reflect.InvocationTargetException;

import org.springframework.beans.TypeConverter;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.support.ArgumentConvertingMethodInvoker;
import org.springframework.lang.Nullable;
import org.springframework.util.ClassUtils;

Simple method invoker bean: just invoking a target method, not expecting a result to expose to the container (in contrast to MethodInvokingFactoryBean). 
This invoker supports any kind of target method. A static method may be specified by setting the targetMethod property to a String representing the static method name, with targetClass specifying the Class that the static method is defined on. Alternatively, a target instance method may be specified, by setting the targetObject property as the target object, and the targetMethod property as the name of the method to call on that target object. Arguments for the method invocation may be specified by setting the arguments property. 
This class depends on afterPropertiesSet() being called once all properties have been set, as per the InitializingBean contract. 
An example (in an XML based bean factory definition) of a bean definition
which uses this class to call a static initialization method:
<bean id="myObject" class="org.springframework.beans.factory.config.MethodInvokingBean">
  <property name="staticMethod" value="com.whatever.MyClass.init"/>
</bean>
An example of calling an instance method to start some server bean:
<bean id="myStarter" class="org.springframework.beans.factory.config.MethodInvokingBean">
  <property name="targetObject" ref="myServer"/>
  <property name="targetMethod" value="start"/>
</bean>
Author:
Juergen Hoeller
See Also:
MethodInvokingFactoryBean
MethodInvoker
Since:
4.0.3/**
 * Simple method invoker bean: just invoking a target method, not expecting a result
 * to expose to the container (in contrast to {@link MethodInvokingFactoryBean}).
 *
 * <p>This invoker supports any kind of target method. A static method may be specified
 * by setting the {@link #setTargetMethod targetMethod} property to a String representing
 * the static method name, with {@link #setTargetClass targetClass} specifying the Class
 * that the static method is defined on. Alternatively, a target instance method may be
 * specified, by setting the {@link #setTargetObject targetObject} property as the target
 * object, and the {@link #setTargetMethod targetMethod} property as the name of the
 * method to call on that target object. Arguments for the method invocation may be
 * specified by setting the {@link #setArguments arguments} property.
 *
 * <p>This class depends on {@link #afterPropertiesSet()} being called once
 * all properties have been set, as per the InitializingBean contract.
 *
 * <p>An example (in an XML based bean factory definition) of a bean definition
 * which uses this class to call a static initialization method:
 *
 * <pre class="code">
 * &lt;bean id="myObject" class="org.springframework.beans.factory.config.MethodInvokingBean">
 *   &lt;property name="staticMethod" value="com.whatever.MyClass.init"/>
 * &lt;/bean></pre>
 *
 * <p>An example of calling an instance method to start some server bean:
 *
 * <pre class="code">
 * &lt;bean id="myStarter" class="org.springframework.beans.factory.config.MethodInvokingBean">
 *   &lt;property name="targetObject" ref="myServer"/>
 *   &lt;property name="targetMethod" value="start"/>
 * &lt;/bean></pre>
 *
 * @author Juergen Hoeller
 * @since 4.0.3
 * @see MethodInvokingFactoryBean
 * @see org.springframework.util.MethodInvoker
 */
public class MethodInvokingBean extends ArgumentConvertingMethodInvoker
		implements BeanClassLoaderAware, BeanFactoryAware, InitializingBean {

	@Nullable
	private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();

	@Nullable
	private ConfigurableBeanFactory beanFactory;


	@Override
	public void setBeanClassLoader(ClassLoader classLoader) {
		this.beanClassLoader = classLoader;
	}

	@Override
	protected Class<?> resolveClassName(String className) throws ClassNotFoundException {
		return ClassUtils.forName(className, this.beanClassLoader);
	}

	@Override
	public void setBeanFactory(BeanFactory beanFactory) {
		if (beanFactory instanceof ConfigurableBeanFactory) {
			this.beanFactory = (ConfigurableBeanFactory) beanFactory;
		}
	}

	
Obtain the TypeConverter from the BeanFactory that this bean runs in,
if possible.
See Also:
getTypeConverter.getTypeConverter()/**
	 * Obtain the TypeConverter from the BeanFactory that this bean runs in,
	 * if possible.
	 * @see ConfigurableBeanFactory#getTypeConverter()
	 */
	@Override
	protected TypeConverter getDefaultTypeConverter() {
		if (this.beanFactory != null) {
			return this.beanFactory.getTypeConverter();
		}
		else {
			return super.getDefaultTypeConverter();
		}
	}


	@Override
	public void afterPropertiesSet() throws Exception {
		prepare();
		invokeWithTargetException();
	}

	
Perform the invocation and convert InvocationTargetException
into the underlying target exception.
/**
	 * Perform the invocation and convert InvocationTargetException
	 * into the underlying target exception.
	 */
	@Nullable
	protected Object invokeWithTargetException() throws Exception {
		try {
			return invoke();
		}
		catch (InvocationTargetException ex) {
			if (ex.getTargetException() instanceof Exception) {
				throw (Exception) ex.getTargetException();
			}
			if (ex.getTargetException() instanceof Error) {
				throw (Error) ex.getTargetException();
			}
			throw ex;
		}
	}

}