论基于数据访问的集合类（Data Access Based Collection）和领域

package oobbs.domainmodel;

import java.util.HashMap;
import java.util.Map;

/**
 * The DomainEventDispatcher take charge of listener registration and dispatch
 * domain event to corresponding listener to handle. Usually, one dispatch per
 * domain object.
 */
public class DomainEventDispatcher {
	/** The listener map. all registered listeners are stored in this map. */
	protected Map<String, DomainObejctListener> listeners = new HashMap<String, DomainObejctListener>();

	/** * Adds a listener. * * @param listener the listener */
	public void addListener(DomainObejctListener listener) {
		listeners.put(listener.getName(), listener);
	}

	/** * Removes all listeners. */
	public void removeAllListeners() {
		listeners.clear();
	}
}

package oobbs.domainmodel.forum;

import oobbs.Constants;
import oobbs.domainmodel.DomainEventDispatcher;
import oobbs.domainmodel.ResultCollector;

/**
 * * The ForumEventDispatcher dispatch all events which about Forum object. * @author
 * laurence.geng
 */
public class ForumEventDispatcher extends DomainEventDispatcher {
	public void dispatch(GetForumThreadEvent event, ResultCollector result) {
		ForumListener forumListener = (ForumListener) listeners.get(Constants.FORUM_REPO_AS_FORUM_LISTENER);
		forumListener.handleGetForumThreadEvent(event, result);
	}

	public void dispatch(GetForumPostCountEvent event, ResultCollector result) {
		ForumListener forumListener = (ForumListener) listeners.get(Constants.FORUM_REPO_AS_FORUM_LISTENER);
		forumListener.handleGetFroumPostCountEvent(event, result);
	}

	public void dispatch(GetForumThreadCountEvent event, ResultCollector result) {
		ForumListener forumListener = (ForumListener) listeners.get(Constants.FORUM_REPO_AS_FORUM_LISTENER);
		forumListener.handleGetForumThreadCountEvent(event, result);
	}
}

package oobbs.domainmodel;

/**
 * The supper class of all domain events. all events should provide event
 * source, the domain object which fired this event.
 */
public class DomainEvent {
	/** The event source, the domain object which fired this event. */
	protected Object source;

	public DomainEvent(Object source) {
		super();
		this.source = source;
	}

	/** * Gets the event source. * * @return the event source */
	public Object getSource() {
		return source;
	}
}

package oobbs.domainmodel.forum;

import oobbs.domainmodel.DomainEvent;

/** 
 * The Event that forum request to get its threads.
 * @author laurence.geng 
 */
public class GetForumThreadEvent extends DomainEvent {
	/** The start index of request thread. */
	private int startIndex;
	/** The count of request thread. */
	private int count;

	public GetForumThreadEvent(Forum source, int startIndex, int count) {
		super(source);
		this.startIndex = startIndex;
		this.count = count;
	}

	public int getStartIndex() {
		return startIndex;
	}

	public int getCount() {
		return count;
	}
}

package oobbs.domainmodel;

/**
 * The super class of all domain object listeners. it handles events from
 * domain objects. Each listener has to provide a name as key for registering
 * itself to dispatcher. 
 * @see DomainObejctEvent 
 * @author laurence.geng
 */
public interface DomainObejctListener {
	/** * Gets the name. * * @return the name */
	public String getName();
}

package oobbs.domainmodel.forum;

import oobbs.domainmodel.DomainObejctListener;
import oobbs.domainmodel.ResultCollector;

/**
 * * The forum listener. It handles all events from Forum object. * * @see
 * ForumEvent * @author laurence.geng
 */
public interface ForumListener extends DomainObejctListener {
	/**
	 * * Handle the event that a forum requests to get its threads. * * @param
	 * event the event * @param result the result
	 */
	public void handleGetForumThreadEvent(GetForumThreadEvent event,ResultCollector result);
}

/**
 * * The Forum's repository with hibernate implementation, besides, it's a forum
 * listener which handle * all events come from forum object.
 */
public class ForumHibernateRepository extends AbstractHibernateRepository<Forum, Long> implements ForumRepository {
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * oobbs.domainmodel.forum.ForumListener#handleGetForumThreadEvent(oobbs
	 * .domainmodel.forum.GetForumThreadEvent,
	 * oobbs.domainmodel.ResultCollector)
	 */
	@Overridepublic
	void handleGetForumThreadEvent(final GetForumThreadEvent event, ResultCollector result) {
		List<Thread> threads = (List<Thread>) getHibernateTemplate().executeWithNativeSession(new HibernateCallback() {
					@SuppressWarnings("unchecked")
					public Object doInHibernate(Session session) throws HibernateException, SQLException {
						logger.info("Start to load threads of forum.");
						// Get forum.
						String getForuumThreadHql = "from Thread as thread where thread.forum=:forum";
						List<Thread> threads = (List<Thread>) session
								.createQuery(getForuumThreadHql)
								.setCacheable(true)
								.setParameter("forum", event.getSource())
								.setFirstResult(event.getStartIndex())
								.setMaxResults(event.getCount()).list();
						return threads;
					}
				});
		result.add(threads);
	}
}

	public List<Thread> getThreads(int startIndex, int count) {
		GetForumThreadEvent event = new GetForumThreadEvent(this, startIndex, count);
		ResultCollector result = new ResultCollector();
		forumEventDispatcher.dispatch(event, result);
		return (List<Thread>) result.getUniqueResult();
	}

package oobbs.infrastructure.appcontext;

import oobbs.domainmodel.DomainObejctListener;
import oobbs.domainmodel.forum.ForumEventDispatcher;
import oobbs.domainmodel.forum.ThreadEventDispatcher;
import org.apache.log4j.Logger;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

/**
 * * The ApplicationBeanPostProcessor will do some initialization work when bean
 * is created by spring ioc container, * such as: Adding listeners for domain
 * event dispatchers and so on. * @author laurence.geng
 */
public class ApplicationBeanPostProcessor implements BeanPostProcessor,
		ApplicationContextAware {
	/** The Constant logger. */
	private static final Logger logger = Logger
			.getLogger(ApplicationBeanPostProcessor.class);
	/** The application context. */
	private ApplicationContext applicationContext;

	/*
	 * (non-Javadoc) * @see org.springframework .beans.factory
	 * .config.BeanPostProcessor #postProcessBeforeInitialization
	 * (java.lang.Object, java.lang.String)
	 */

	public Object postProcessBeforeInitialization(Object bean, String beanName)	throws BeansException {
		return bean; // we could potentially return any object reference here...
	}

	/*
	 * (non-Javadoc) * @see
	 * org.springframework.beans.factory.config.BeanPostProcessor
	 * #postProcessAfterInitialization(java.lang.Object, java.lang.String)
	 */
	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
		logger.debug("Bean '" + beanName + "' created : " + bean.toString());
		// Adding listeners for domain event dispatchers.
		if ("forumEventDispatcher".equals(beanName)) {
			ForumEventDispatcher forumEventDispatcher = (ForumEventDispatcher) bean;
			forumEventDispatcher.addListener((DomainObejctListener) applicationContext.getBean("forumRepository"));
		}
		if ("threadEventDispatcher".equals(beanName)) {
			ThreadEventDispatcher threadEventDispatcher = (ThreadEventDispatcher) bean;
			threadEventDispatcher.addListener((DomainObejctListener) applicationContext.getBean("threadRepository"));
		}
		return bean;
	}

	/*
	 * (non-Javadoc) * @see
	 * org.springframework.context.ApplicationContextAware#setApplicationContext
	 * (org.springframework.context.ApplicationContext)
	 */
	@Override
	public void setApplicationContext(ApplicationContext arg0) throws BeansException {
		this.applicationContext = arg0;
	}
}