HibernateAndSpringEnabledExecuteAndWaitInterceptor - WebWork2文档中文化计划

下面是一个扩展ExecuteAndWaitInterceptor的例子.

这段代码的目的是允许在后台执行的同时可以访问到相同的打开的Hibernate Session对象

SessionFactory的依赖是通过Spring注射到OpenSessionExecuteAndWaitInterceptor里面的. 你也可以使用其它的依赖注入方法, 如果更适合的话. 通过覆写getNewBackgroundProcess()方法, 这个拦截器使用自定义OpenSessionBackgroundProcess而不是WebWork默认的.

覆写了OpenSessionBackgroundProcess中的beforeInvocation()和afterInvocation()方法来确保在后台处理过程中session一直处于打开状态, 任何Spring的事务管理都是可用的.

这个代码依赖于Spring和Hibernate, 所以你不可能在Webwork的发布包中看见它. 尽管如此, 这是个扩展misc:Execute and Wait Interceptor的一个很有用的例子.

OpenSessionExecuteAndWaitInterceptor.java

import net.sf.hibernate.SessionFactory;

import com.opensymphony.webwork.interceptor.BackgroundProcess;
import com.opensymphony.webwork.interceptor.ExecuteAndWaitInterceptor;
import com.opensymphony.xwork.ActionInvocation;


/**
 * The OpenSessionExecuteAndWaitInterceptor will obtain a Hibernate
 * Session Factory from a Spring.
 * 
 * The session factory will then be passed to the BackgroundProcess,
 * to open a session, enable Spring's transaction management 
 * capabilities, and bind the Session to the background thread.
 * 
 */
public class OpenSessionExecuteAndWaitInterceptor extends ExecuteAndWaitInterceptor {
       
    SessionFactory sessionFactory;

    
	public SessionFactory getSessionFactory() {
		return sessionFactory;
	}


	public void setSessionFactory(SessionFactory sessionFactory) {
		this.sessionFactory = sessionFactory;
	}

	protected BackgroundProcess getNewBackgroundProcess(String arg0, ActionInvocation arg1, int arg2) {
		return new OpenSessionBackgroundProcess(arg0, arg1, arg2, sessionFactory);
	}

}

OpenSessionBackgroundProcess.java

import net.sf.hibernate.FlushMode;
import net.sf.hibernate.Session;
import net.sf.hibernate.SessionFactory;

import org.springframework.orm.hibernate.SessionFactoryUtils;
import org.springframework.orm.hibernate.SessionHolder;
import org.springframework.transaction.support.TransactionSynchronizationManager;

import com.opensymphony.webwork.interceptor.BackgroundProcess;
import com.opensymphony.xwork.ActionInvocation;

/**
 * The OpenSessionBackgroundProcess, when instantiated with a
 * HibernateSessionFactory, will open a session, enable Spring's transaction
 * management capabilities, and bind the Session to the background thread.
 * 
 */
public class OpenSessionBackgroundProcess extends BackgroundProcess {

	SessionFactory sessionFactory;

	Session openSession;

	public OpenSessionBackgroundProcess(String name,
			ActionInvocation invocation, int threadPriority,
			SessionFactory factory) {
		super(name, invocation, threadPriority);
		this.sessionFactory = factory;
	}

	protected void beforeInvocation() throws Exception {
		openSession = SessionFactoryUtils.getSession(sessionFactory, true);
		openSession.setFlushMode(FlushMode.NEVER);
		TransactionSynchronizationManager.bindResource(sessionFactory,
				new SessionHolder(openSession));
		super.beforeInvocation();
	}

	protected void afterInvocation() throws Exception {
		super.afterInvocation();
		TransactionSynchronizationManager.unbindResource(sessionFactory);
		SessionFactoryUtils
				.closeSessionIfNecessary(openSession, sessionFactory);
	}


}