/*
 * Copyright (C) 2005-2007 Alfresco Software Limited.
 *
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 * As a special exception to the terms and conditions of version 2.0 of 
 * the GPL, you may redistribute this Program in connection with Free/Libre 
 * and Open Source Software ("FLOSS") applications as described in Alfresco's 
 * FLOSS exception.  You should have recieved a copy of the text describing 
 * the FLOSS exception, and it is also available here: 
 * http://www.alfresco.com/legal/licensing"
 */
package org.alfresco.repo.content;

import org.alfresco.repo.policy.ClassPolicy;
import org.alfresco.service.cmr.repository.ContentData;
import org.alfresco.service.cmr.repository.NodeRef;
import org.alfresco.service.namespace.NamespaceService;
import org.alfresco.service.namespace.QName;

/**
 * Content service policies interface
 * 
 * @author Roy Wetherall
 * @author Derek Hulley
 */
public interface ContentServicePolicies
{
    /** The QName's of the policies */
    public static final QName ON_CONTENT_UPDATE = QName.createQName(NamespaceService.ALFRESCO_URI, "onContentUpdate");
    public static final QName ON_CONTENT_PROPERTY_UPDATE = QName.createQName(NamespaceService.ALFRESCO_URI, "onContentPropertyUpdate");
    public static final QName ON_CONTENT_READ = QName.createQName(NamespaceService.ALFRESCO_URI, "onContentRead");
    
	/**
	 * Policy that is raised once per node when any of the content properties on the node are
	 * changed; the specific properties are irrelevant.  This is primarily useful to determine
	 * when a new file is introduced into the system.
	 */
	public interface OnContentUpdatePolicy extends ClassPolicy
	{
		/**
		 * @param nodeRef	the node reference
		 */
		public void onContentUpdate(NodeRef nodeRef, boolean newContent);
	}
    
    /**
     * Policy that is raised for each content property change.  Any policy implementations must be aware
     * that the transaction in which this is called could still roll back; no filesystem changes should
     * occur against the source content until after the transaction has <u>successfully</u> completed.
     * 
     * @since 3.2
     */
    public interface OnContentPropertyUpdatePolicy extends ClassPolicy
    {
        /**
         * @param nodeRef           the node reference
         * @param propertyQName     the name of the property that changed
         * @param beforeValue       the value of the content data prior to the change.
         *                          Note that this value may be <tt>null</tt> or any of it's member
         *                          values may be <tt>null</tt> according to the contract of the
         *                          {@link ContentData} class.
         * @param afterValue        the value of the content data after the change
         * 
         * @see ContentData#hasContent(ContentData)
         * @see RoutingContentService#onUpdateProperties(NodeRef, java.util.Map, java.util.Map)
         * @since 3.2
         */
        public void onContentPropertyUpdate(
                NodeRef nodeRef,
                QName propertyQName,
                ContentData beforeValue,
                ContentData afterValue);
    }
    
    /**
     * On content read policy interface.
     * 
     * This policy is fired when a content reader is requested for a node that has content.
     */
    public interface OnContentReadPolicy extends ClassPolicy
    {
        /**
         * @param nodeRef   the node reference
         */
        public void onContentRead(NodeRef nodeRef);
    }
}