https://github.com/spring-projects/spring-framework: Spring Beans (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2018 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.support;

import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.security.AccessControlContext;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.beans.factory.config.DestructionAwareBeanPostProcessor;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.StringUtils;


Adapter that implements the DisposableBean and Runnable interfaces performing various destruction steps on a given bean instance: 
    

  • DestructionAwareBeanPostProcessors;

  • the bean implementing DisposableBean itself;

  • a custom destroy method specified on the bean definition.



Author:Juergen Hoeller, Costin Leau, Stephane Nicoll
See Also:
Since:2.0
/**
 * Adapter that implements the {@link DisposableBean} and {@link Runnable}
 * interfaces performing various destruction steps on a given bean instance:
 * <ul>
 * <li>DestructionAwareBeanPostProcessors;
 * <li>the bean implementing DisposableBean itself;
 * <li>a custom destroy method specified on the bean definition.
 * </ul>
 *
 * @author Juergen Hoeller
 * @author Costin Leau
 * @author Stephane Nicoll
 * @since 2.0
 * @see AbstractBeanFactory
 * @see org.springframework.beans.factory.DisposableBean
 * @see org.springframework.beans.factory.config.DestructionAwareBeanPostProcessor
 * @see AbstractBeanDefinition#getDestroyMethodName()
 */
@SuppressWarnings("serial")
class DisposableBeanAdapter implements DisposableBean, Runnable, Serializable {

	private static final String CLOSE_METHOD_NAME = "close";

	private static final String SHUTDOWN_METHOD_NAME = "shutdown";

	private static final Log logger = LogFactory.getLog(DisposableBeanAdapter.class);


	private final Object bean;

	private final String beanName;

	private final boolean invokeDisposableBean;

	private final boolean nonPublicAccessAllowed;

	@Nullable
	private final AccessControlContext acc;

	@Nullable
	private String destroyMethodName;

	@Nullable
	private transient Method destroyMethod;

	@Nullable
	private List<DestructionAwareBeanPostProcessor> beanPostProcessors;


	
Create a new DisposableBeanAdapter for the given bean.

Params:
  • bean – the bean instance (never null)
  • beanName – the name of the bean
  • beanDefinition – the merged bean definition
  • postProcessors – the List of BeanPostProcessors
(potentially DestructionAwareBeanPostProcessor), if any
/**
	 * Create a new DisposableBeanAdapter for the given bean.
	 * @param bean the bean instance (never {@code null})
	 * @param beanName the name of the bean
	 * @param beanDefinition the merged bean definition
	 * @param postProcessors the List of BeanPostProcessors
	 * (potentially DestructionAwareBeanPostProcessor), if any
	 */
	public DisposableBeanAdapter(Object bean, String beanName, RootBeanDefinition beanDefinition,
			List<BeanPostProcessor> postProcessors, @Nullable AccessControlContext acc) {

		Assert.notNull(bean, "Disposable bean must not be null");
		this.bean = bean;
		this.beanName = beanName;
		this.invokeDisposableBean =
				(this.bean instanceof DisposableBean && !beanDefinition.isExternallyManagedDestroyMethod("destroy"));
		this.nonPublicAccessAllowed = beanDefinition.isNonPublicAccessAllowed();
		this.acc = acc;
		String destroyMethodName = inferDestroyMethodIfNecessary(bean, beanDefinition);
		if (destroyMethodName != null && !(this.invokeDisposableBean && "destroy".equals(destroyMethodName)) &&
				!beanDefinition.isExternallyManagedDestroyMethod(destroyMethodName)) {
			this.destroyMethodName = destroyMethodName;
			this.destroyMethod = determineDestroyMethod(destroyMethodName);
			if (this.destroyMethod == null) {
				if (beanDefinition.isEnforceDestroyMethod()) {
					throw new BeanDefinitionValidationException("Could not find a destroy method named '" +
							destroyMethodName + "' on bean with name '" + beanName + "'");
				}
			}
			else {
				Class<?>[] paramTypes = this.destroyMethod.getParameterTypes();
				if (paramTypes.length > 1) {
					throw new BeanDefinitionValidationException("Method '" + destroyMethodName + "' of bean '" +
							beanName + "' has more than one parameter - not supported as destroy method");
				}
				else if (paramTypes.length == 1 && boolean.class != paramTypes[0]) {
					throw new BeanDefinitionValidationException("Method '" + destroyMethodName + "' of bean '" +
							beanName + "' has a non-boolean parameter - not supported as destroy method");
				}
			}
		}
		this.beanPostProcessors = filterPostProcessors(postProcessors, bean);
	}

	
Create a new DisposableBeanAdapter for the given bean.

Params:
  • bean – the bean instance (never null)
  • postProcessors – the List of BeanPostProcessors
(potentially DestructionAwareBeanPostProcessor), if any
/**
	 * Create a new DisposableBeanAdapter for the given bean.
	 * @param bean the bean instance (never {@code null})
	 * @param postProcessors the List of BeanPostProcessors
	 * (potentially DestructionAwareBeanPostProcessor), if any
	 */
	public DisposableBeanAdapter(Object bean, List<BeanPostProcessor> postProcessors, AccessControlContext acc) {
		Assert.notNull(bean, "Disposable bean must not be null");
		this.bean = bean;
		this.beanName = bean.getClass().getName();
		this.invokeDisposableBean = (this.bean instanceof DisposableBean);
		this.nonPublicAccessAllowed = true;
		this.acc = acc;
		this.beanPostProcessors = filterPostProcessors(postProcessors, bean);
	}

	
Create a new DisposableBeanAdapter for the given bean.

/**
	 * Create a new DisposableBeanAdapter for the given bean.
	 */
	private DisposableBeanAdapter(Object bean, String beanName, boolean invokeDisposableBean,
			boolean nonPublicAccessAllowed, @Nullable String destroyMethodName,
			@Nullable List<DestructionAwareBeanPostProcessor> postProcessors) {

		this.bean = bean;
		this.beanName = beanName;
		this.invokeDisposableBean = invokeDisposableBean;
		this.nonPublicAccessAllowed = nonPublicAccessAllowed;
		this.acc = null;
		this.destroyMethodName = destroyMethodName;
		this.beanPostProcessors = postProcessors;
	}


	
If the current value of the given beanDefinition's "destroyMethodName" property is AbstractBeanDefinition.INFER_METHOD, then attempt to infer a destroy method. Candidate methods are currently limited to public, no-arg methods named "close" or "shutdown" (whether declared locally or inherited). The given BeanDefinition's "destroyMethodName" is updated to be null if no such method is found, otherwise set to the name of the inferred method. This constant serves as the default for the @Bean#destroyMethod attribute and the value of the constant may also be used in XML within the <bean destroy-method=""> or 
<beans default-destroy-method=""> attributes. 
Also processes the Closeable and AutoCloseable interfaces, reflectively calling the "close" method on implementing beans as well. 
/**
	 * If the current value of the given beanDefinition's "destroyMethodName" property is
	 * {@link AbstractBeanDefinition#INFER_METHOD}, then attempt to infer a destroy method.
	 * Candidate methods are currently limited to public, no-arg methods named "close" or
	 * "shutdown" (whether declared locally or inherited). The given BeanDefinition's
	 * "destroyMethodName" is updated to be null if no such method is found, otherwise set
	 * to the name of the inferred method. This constant serves as the default for the
	 * {@code @Bean#destroyMethod} attribute and the value of the constant may also be
	 * used in XML within the {@code <bean destroy-method="">} or {@code
	 * <beans default-destroy-method="">} attributes.
	 * <p>Also processes the {@link java.io.Closeable} and {@link java.lang.AutoCloseable}
	 * interfaces, reflectively calling the "close" method on implementing beans as well.
	 */
	@Nullable
	private String inferDestroyMethodIfNecessary(Object bean, RootBeanDefinition beanDefinition) {
		String destroyMethodName = beanDefinition.getDestroyMethodName();
		if (AbstractBeanDefinition.INFER_METHOD.equals(destroyMethodName) ||
				(destroyMethodName == null && bean instanceof AutoCloseable)) {
			// Only perform destroy method inference or Closeable detection
			// in case of the bean not explicitly implementing DisposableBean
			if (!(bean instanceof DisposableBean)) {
				try {
					return bean.getClass().getMethod(CLOSE_METHOD_NAME).getName();
				}
				catch (NoSuchMethodException ex) {
					try {
						return bean.getClass().getMethod(SHUTDOWN_METHOD_NAME).getName();
					}
					catch (NoSuchMethodException ex2) {
						// no candidate destroy method found
					}
				}
			}
			return null;
		}
		return (StringUtils.hasLength(destroyMethodName) ? destroyMethodName : null);
	}

	
Search for all DestructionAwareBeanPostProcessors in the List.

Params:
  • processors – the List to search
Returns:the filtered List of DestructionAwareBeanPostProcessors
/**
	 * Search for all DestructionAwareBeanPostProcessors in the List.
	 * @param processors the List to search
	 * @return the filtered List of DestructionAwareBeanPostProcessors
	 */
	@Nullable
	private List<DestructionAwareBeanPostProcessor> filterPostProcessors(List<BeanPostProcessor> processors, Object bean) {
		List<DestructionAwareBeanPostProcessor> filteredPostProcessors = null;
		if (!CollectionUtils.isEmpty(processors)) {
			filteredPostProcessors = new ArrayList<>(processors.size());
			for (BeanPostProcessor processor : processors) {
				if (processor instanceof DestructionAwareBeanPostProcessor) {
					DestructionAwareBeanPostProcessor dabpp = (DestructionAwareBeanPostProcessor) processor;
					if (dabpp.requiresDestruction(bean)) {
						filteredPostProcessors.add(dabpp);
					}
				}
			}
		}
		return filteredPostProcessors;
	}


	@Override
	public void run() {
		destroy();
	}

	@Override
	public void destroy() {
		if (!CollectionUtils.isEmpty(this.beanPostProcessors)) {
			for (DestructionAwareBeanPostProcessor processor : this.beanPostProcessors) {
				processor.postProcessBeforeDestruction(this.bean, this.beanName);
			}
		}

		if (this.invokeDisposableBean) {
			if (logger.isTraceEnabled()) {
				logger.trace("Invoking destroy() on bean with name '" + this.beanName + "'");
			}
			try {
				if (System.getSecurityManager() != null) {
					AccessController.doPrivileged((PrivilegedExceptionAction<Object>) () -> {
						((DisposableBean) this.bean).destroy();
						return null;
					}, this.acc);
				}
				else {
					((DisposableBean) this.bean).destroy();
				}
			}
			catch (Throwable ex) {
				String msg = "Invocation of destroy method failed on bean with name '" + this.beanName + "'";
				if (logger.isDebugEnabled()) {
					logger.info(msg, ex);
				}
				else {
					logger.info(msg + ": " + ex);
				}
			}
		}

		if (this.destroyMethod != null) {
			invokeCustomDestroyMethod(this.destroyMethod);
		}
		else if (this.destroyMethodName != null) {
			Method methodToCall = determineDestroyMethod(this.destroyMethodName);
			if (methodToCall != null) {
				invokeCustomDestroyMethod(methodToCall);
			}
		}
	}


	@Nullable
	private Method determineDestroyMethod(String name) {
		try {
			if (System.getSecurityManager() != null) {
				return AccessController.doPrivileged((PrivilegedAction<Method>) () -> findDestroyMethod(name));
			}
			else {
				return findDestroyMethod(name);
			}
		}
		catch (IllegalArgumentException ex) {
			throw new BeanDefinitionValidationException("Could not find unique destroy method on bean with name '" +
					this.beanName + ": " + ex.getMessage());
		}
	}

	@Nullable
	private Method findDestroyMethod(String name) {
		return (this.nonPublicAccessAllowed ?
				BeanUtils.findMethodWithMinimalParameters(this.bean.getClass(), name) :
				BeanUtils.findMethodWithMinimalParameters(this.bean.getClass().getMethods(), name));
	}

	
Invoke the specified custom destroy method on the given bean.

This implementation invokes a no-arg method if found, else checking
for a method with a single boolean argument (passing in "true",
assuming a "force" parameter), else logging an error.

/**
	 * Invoke the specified custom destroy method on the given bean.
	 * <p>This implementation invokes a no-arg method if found, else checking
	 * for a method with a single boolean argument (passing in "true",
	 * assuming a "force" parameter), else logging an error.
	 */
	private void invokeCustomDestroyMethod(final Method destroyMethod) {
		Class<?>[] paramTypes = destroyMethod.getParameterTypes();
		final Object[] args = new Object[paramTypes.length];
		if (paramTypes.length == 1) {
			args[0] = Boolean.TRUE;
		}
		if (logger.isTraceEnabled()) {
			logger.trace("Invoking destroy method '" + this.destroyMethodName +
					"' on bean with name '" + this.beanName + "'");
		}
		try {
			if (System.getSecurityManager() != null) {
				AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
					ReflectionUtils.makeAccessible(destroyMethod);
					return null;
				});
				try {
					AccessController.doPrivileged((PrivilegedExceptionAction<Object>) () ->
						destroyMethod.invoke(this.bean, args), this.acc);
				}
				catch (PrivilegedActionException pax) {
					throw (InvocationTargetException) pax.getException();
				}
			}
			else {
				ReflectionUtils.makeAccessible(destroyMethod);
				destroyMethod.invoke(this.bean, args);
			}
		}
		catch (InvocationTargetException ex) {
			String msg = "Destroy method '" + this.destroyMethodName + "' on bean with name '" +
					this.beanName + "' threw an exception";
			if (logger.isDebugEnabled()) {
				logger.info(msg, ex.getTargetException());
			}
			else {
				logger.info(msg + ": " + ex.getTargetException());
			}
		}
		catch (Throwable ex) {
			logger.info("Failed to invoke destroy method '" + this.destroyMethodName +
					"' on bean with name '" + this.beanName + "'", ex);
		}
	}


	
Serializes a copy of the state of this class,
filtering out non-serializable BeanPostProcessors.

/**
	 * Serializes a copy of the state of this class,
	 * filtering out non-serializable BeanPostProcessors.
	 */
	protected Object writeReplace() {
		List<DestructionAwareBeanPostProcessor> serializablePostProcessors = null;
		if (this.beanPostProcessors != null) {
			serializablePostProcessors = new ArrayList<>();
			for (DestructionAwareBeanPostProcessor postProcessor : this.beanPostProcessors) {
				if (postProcessor instanceof Serializable) {
					serializablePostProcessors.add(postProcessor);
				}
			}
		}
		return new DisposableBeanAdapter(this.bean, this.beanName, this.invokeDisposableBean,
				this.nonPublicAccessAllowed, this.destroyMethodName, serializablePostProcessors);
	}


	
Check whether the given bean has any kind of destroy method to call.

Params:
  • bean – the bean instance
  • beanDefinition – the corresponding bean definition
/**
	 * Check whether the given bean has any kind of destroy method to call.
	 * @param bean the bean instance
	 * @param beanDefinition the corresponding bean definition
	 */
	public static boolean hasDestroyMethod(Object bean, RootBeanDefinition beanDefinition) {
		if (bean instanceof DisposableBean || bean instanceof AutoCloseable) {
			return true;
		}
		String destroyMethodName = beanDefinition.getDestroyMethodName();
		if (AbstractBeanDefinition.INFER_METHOD.equals(destroyMethodName)) {
			return (ClassUtils.hasMethod(bean.getClass(), CLOSE_METHOD_NAME) ||
					ClassUtils.hasMethod(bean.getClass(), SHUTDOWN_METHOD_NAME));
		}
		return StringUtils.hasLength(destroyMethodName);
	}

	
Check whether the given bean has destruction-aware post-processors applying to it.

Params:
  • bean – the bean instance
  • postProcessors – the post-processor candidates
/**
	 * Check whether the given bean has destruction-aware post-processors applying to it.
	 * @param bean the bean instance
	 * @param postProcessors the post-processor candidates
	 */
	public static boolean hasApplicableProcessors(Object bean, List<BeanPostProcessor> postProcessors) {
		if (!CollectionUtils.isEmpty(postProcessors)) {
			for (BeanPostProcessor processor : postProcessors) {
				if (processor instanceof DestructionAwareBeanPostProcessor) {
					DestructionAwareBeanPostProcessor dabpp = (DestructionAwareBeanPostProcessor) processor;
					if (dabpp.requiresDestruction(bean)) {
						return true;
					}
				}
			}
		}
		return false;
	}

}