actionqueue.java

一个Java持久层类库

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2007, Red Hat Middleware LLC or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 *
 */
package org.hibernate.engine;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.hibernate.AssertionFailure;
import org.hibernate.HibernateException;
import org.hibernate.action.BulkOperationCleanupAction;
import org.hibernate.action.CollectionRecreateAction;
import org.hibernate.action.CollectionRemoveAction;
import org.hibernate.action.CollectionUpdateAction;
import org.hibernate.action.EntityDeleteAction;
import org.hibernate.action.EntityIdentityInsertAction;
import org.hibernate.action.EntityInsertAction;
import org.hibernate.action.EntityUpdateAction;
import org.hibernate.action.Executable;
import org.hibernate.cache.CacheException;
import org.hibernate.type.Type;

/**
 * Responsible for maintaining the queue of actions related to events.
 * </p>
 * The ActionQueue holds the DML operations queued as part of a session's
 * transactional-write-behind semantics.  DML operations are queued here
 * until a flush forces them to be executed against the database.
 *
 * @author Steve Ebersole
 */
public class ActionQueue {

	private static final Logger log = LoggerFactory.getLogger( ActionQueue.class );
	private static final int INIT_QUEUE_LIST_SIZE = 5;

	private SessionImplementor session;

	// Object insertions, updates, and deletions have list semantics because
	// they must happen in the right order so as to respect referential
	// integrity
	private ArrayList insertions;
	private ArrayList deletions;
	private ArrayList updates;
	// Actually the semantics of the next three are really "Bag"
	// Note that, unlike objects, collection insertions, updates,
	// deletions are not really remembered between flushes. We
	// just re-use the same Lists for convenience.
	private ArrayList collectionCreations;
	private ArrayList collectionUpdates;
	private ArrayList collectionRemovals;

	private ArrayList executions;

	/**
	 * Constructs an action queue bound to the given session.
	 *
	 * @param session The session "owning" this queue.
	 */
	public ActionQueue(SessionImplementor session) {
		this.session = session;
		init();
	}

	private void init() {
		insertions = new ArrayList( INIT_QUEUE_LIST_SIZE );
		deletions = new ArrayList( INIT_QUEUE_LIST_SIZE );
		updates = new ArrayList( INIT_QUEUE_LIST_SIZE );

		collectionCreations = new ArrayList( INIT_QUEUE_LIST_SIZE );
		collectionRemovals = new ArrayList( INIT_QUEUE_LIST_SIZE );
		collectionUpdates = new ArrayList( INIT_QUEUE_LIST_SIZE );

		executions = new ArrayList( INIT_QUEUE_LIST_SIZE * 3 );
	}

	public void clear() {
		updates.clear();
		insertions.clear();
		deletions.clear();

		collectionCreations.clear();
		collectionRemovals.clear();
		collectionUpdates.clear();
	}

	public void addAction(EntityInsertAction action) {
		insertions.add( action );
	}

	public void addAction(EntityDeleteAction action) {
		deletions.add( action );
	}

	public void addAction(EntityUpdateAction action) {
		updates.add( action );
	}

	public void addAction(CollectionRecreateAction action) {
		collectionCreations.add( action );
	}

	public void addAction(CollectionRemoveAction action) {
		collectionRemovals.add( action );
	}

	public void addAction(CollectionUpdateAction action) {
		collectionUpdates.add( action );
	}

	public void addAction(EntityIdentityInsertAction insert) {
		insertions.add( insert );
	}

	public void addAction(BulkOperationCleanupAction cleanupAction) {
		// Add these directly to the executions queue
		executions.add( cleanupAction );
	}

	/**
	 * Perform all currently queued entity-insertion actions.
	 *
	 * @throws HibernateException error executing queued insertion actions.
	 */
	public void executeInserts() throws HibernateException {
		executeActions( insertions );
	}

	/**
	 * Perform all currently queued actions.
	 *
	 * @throws HibernateException error executing queued actions.
	 */
	public void executeActions() throws HibernateException {
		executeActions( insertions );
		executeActions( updates );
		executeActions( collectionRemovals );
		executeActions( collectionUpdates );
		executeActions( collectionCreations );
		executeActions( deletions );
	}

	/**
	 * Prepares the internal action queues for execution.
	 *
	 * @throws HibernateException error preparing actions.
	 */
	public void prepareActions() throws HibernateException {
		prepareActions( collectionRemovals );
		prepareActions( collectionUpdates );
		prepareActions( collectionCreations );
	}

	/**
	 * Performs cleanup of any held cache softlocks.
	 *
	 * @param success Was the transaction successful.
	 */
	public void afterTransactionCompletion(boolean success) {
		int size = executions.size();
		final boolean invalidateQueryCache = session.getFactory().getSettings().isQueryCacheEnabled();
		for ( int i = 0; i < size; i++ ) {
			try {
				Executable exec = ( Executable ) executions.get( i );
				try {
					exec.afterTransactionCompletion( success );
				}
				finally {
					if ( invalidateQueryCache ) {
						session.getFactory().getUpdateTimestampsCache().invalidate( exec.getPropertySpaces() );
					}
				}
			}
			catch ( CacheException ce ) {
				log.error( "could not release a cache lock", ce );
				// continue loop
			}
			catch ( Exception e ) {
				throw new AssertionFailure( "Exception releasing cache locks", e );
			}
		}
		executions.clear();
	}

	/**
	 * Check whether the given tables/query-spaces are to be executed against
	 * given the currently queued actions.
	 *
	 * @param tables The table/query-spaces to check.
	 *
	 * @return True if we contain pending actions against any of the given
	 *         tables; false otherwise.
	 */
	public boolean areTablesToBeUpdated(Set tables) {
		return areTablesToUpdated( updates, tables ) ||
				areTablesToUpdated( insertions, tables ) ||
				areTablesToUpdated( deletions, tables ) ||
				areTablesToUpdated( collectionUpdates, tables ) ||
				areTablesToUpdated( collectionCreations, tables ) ||
				areTablesToUpdated( collectionRemovals, tables );
	}

	/**
	 * Check whether any insertion or deletion actions are currently queued.
	 *
	 * @return True if insertions or deletions are currently queued; false otherwise.
	 */
	public boolean areInsertionsOrDeletionsQueued() {
		return ( insertions.size() > 0 || deletions.size() > 0 );
	}

	private static boolean areTablesToUpdated(List executables, Set tablespaces) {
		int size = executables.size();
		for ( int j = 0; j < size; j++ ) {
			Serializable[] spaces = ( ( Executable ) executables.get( j ) ).getPropertySpaces();
			for ( int i = 0; i < spaces.length; i++ ) {
				if ( tablespaces.contains( spaces[i] ) ) {
					if ( log.isDebugEnabled() ) {
						log.debug( "changes must be flushed to space: " + spaces[i] );
					}
					return true;
				}
			}
		}
		return false;
	}

	private void executeActions(List list) throws HibernateException {
		int size = list.size();
		for ( int i = 0; i < size; i++ ) {
			execute( ( Executable ) list.get( i ) );
		}
		list.clear();
		session.getBatcher().executeBatch();
	}

	public void execute(Executable executable) {
		final boolean lockQueryCache = session.getFactory().getSettings().isQueryCacheEnabled();
		if ( executable.hasAfterTransactionCompletion() || lockQueryCache ) {
			executions.add( executable );
		}
		if ( lockQueryCache ) {
			session.getFactory()
					.getUpdateTimestampsCache()
					.preinvalidate( executable.getPropertySpaces() );
		}
		executable.execute();
	}

	private void prepareActions(List queue) throws HibernateException {
		int size = queue.size();
		for ( int i = 0; i < size; i++ ) {
			Executable executable = ( Executable ) queue.get( i );
			executable.beforeExecutions();
		}
	}

	/**
	 * Returns a string representation of the object.
	 *
	 * @return a string representation of the object.
	 */
	public String toString() {
		return new StringBuffer()
				.append( "ActionQueue[insertions=" ).append( insertions )
				.append( " updates=" ).append( updates )
				.append( " deletions=" ).append( deletions )
				.append( " collectionCreations=" ).append( collectionCreations )
				.append( " collectionRemovals=" ).append( collectionRemovals )
				.append( " collectionUpdates=" ).append( collectionUpdates )
				.append( "]" )
				.toString();
	}

	public int numberOfCollectionRemovals() {
		return collectionRemovals.size();
	}