cn.taketoday.aop.target.AbstractPoolingTargetSource Maven / Gradle / Ivy
/*
* Original Author -> Harry Yang ([email protected]) https://taketoday.cn
* Copyright © TODAY & 2017 - 2021 All Rights Reserved.
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see [http://www.gnu.org/licenses/]
*/
package cn.taketoday.aop.target;
import cn.taketoday.aop.TargetSource;
import cn.taketoday.aop.support.DefaultIntroductionAdvisor;
import cn.taketoday.aop.support.DelegatingIntroductionInterceptor;
import cn.taketoday.beans.BeansException;
import cn.taketoday.beans.factory.BeanFactory;
import cn.taketoday.beans.factory.BeanInitializationException;
import cn.taketoday.beans.factory.DisposableBean;
import cn.taketoday.lang.Nullable;
/**
* Abstract base class for pooling {@link TargetSource}
* implementations which maintain a pool of target instances, acquiring and
* releasing a target object from the pool for each method invocation.
* This abstract base class is independent of concrete pooling technology;
* see the subclass {@link CommonsPool2TargetSource} for a concrete example.
*
* Subclasses must implement the {@link #getTarget} and
* {@link #releaseTarget} methods based on their chosen object pool.
* The {@link #newPrototypeInstance()} method inherited from
* {@link AbstractPrototypeTargetSource} can be used to create objects
* in order to put them into the pool.
*
*
Subclasses must also implement some of the monitoring methods from the
* {@link PoolingConfig} interface. The {@link #getPoolingConfigMixin()} method
* makes these stats available on proxied objects through an IntroductionAdvisor.
*
*
This class implements the {@link cn.taketoday.beans.factory.DisposableBean}
* interface in order to force subclasses to implement a {@link #destroy()}
* method, closing down their object pool.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @see #getTarget
* @see #releaseTarget
* @see #destroy
* @since 4.0
*/
@SuppressWarnings("serial")
public abstract class AbstractPoolingTargetSource
extends AbstractPrototypeTargetSource implements PoolingConfig, DisposableBean {
/** The maximum size of the pool. */
private int maxSize = -1;
/**
* Set the maximum size of the pool.
* Default is -1, indicating no size limit.
*/
public void setMaxSize(int maxSize) {
this.maxSize = maxSize;
}
/**
* Return the maximum size of the pool.
*/
@Override
public int getMaxSize() {
return this.maxSize;
}
@Override
public final void setBeanFactory(BeanFactory beanFactory) throws BeansException {
super.setBeanFactory(beanFactory);
try {
createPool();
}
catch (Throwable ex) {
throw new BeanInitializationException("Could not create instance pool for TargetSource", ex);
}
}
/**
* Create the pool.
*
* @throws Exception to avoid placing constraints on pooling APIs
*/
protected abstract void createPool() throws Exception;
/**
* Acquire an object from the pool.
*
* @return an object from the pool
* @throws Exception we may need to deal with checked exceptions from pool
* APIs, so we're forgiving with our exception signature
*/
@Override
@Nullable
public abstract Object getTarget() throws Exception;
/**
* Return the given object to the pool.
*
* @param target object that must have been acquired from the pool
* via a call to {@code getTarget()}
* @throws Exception to allow pooling APIs to throw exception
* @see #getTarget
*/
@Override
public abstract void releaseTarget(Object target) throws Exception;
/**
* Return an IntroductionAdvisor that provides a mixin
* exposing statistics about the pool maintained by this object.
*/
public DefaultIntroductionAdvisor getPoolingConfigMixin() {
DelegatingIntroductionInterceptor dii = new DelegatingIntroductionInterceptor(this);
return new DefaultIntroductionAdvisor(dii, PoolingConfig.class);
}
}