// This Source Code is in the Public Domain per: http://unlicense.org
package org.litesoft.bo.views.caching;

import java.util.*;

import org.litesoft.bo.views.*;

public interface VoCacheManager
{
    /**
     * Remove all CacheID tracking associated with the pUserSessionID.
     *
     * @param pUserSessionID An Object supporting appropriate "equals()" that will uniquely identify a UserSession on the current server
     */
    void drop( Object pUserSessionID );

    /**
     * Add monitoring for a ViewObject Type (Class Name)
     *
     * @param pUserSessionID An Object supporting appropriate "equals()" that will uniquely identify a UserSession on the current server
     */
    void addType( Object pUserSessionID, CacheID pCacheID, String pViewObjectClassName );

    /**
     * Add monitoring for a ViewObject Instance (via its ObjectURL)
     *
     * @param pUserSessionID An Object supporting appropriate "equals()" that will uniquely identify a UserSession on the current server
     */
    void addInstance( Object pUserSessionID, CacheID pCacheID, ObjectURL pObjectURL );

    /**
     * For each ObjectURL, move any CacheIDs into the Invalid Collectors, and then return the Invalid Collection for this UserSession!
     * <p/>
     * Note: The CacheIDs that have been registered have been registered by multiple UserSessions, so... this means that any pObjectURLs
     * may effect CacheIDs from other UserSessions and must be "held" as invalidated until the UserSession contacts the Server!
     *
     * @param pUserSessionID An Object supporting appropriate "equals()" that will uniquely identify a UserSession on the current server
     * @param pObjectURLs    (may be null and contain nulls) for ViewObjects that were changed or created; these will be used to invalidate previously added CacheIDs
     */
    CacheID[] invalidate( Object pUserSessionID, List<ObjectURL> pObjectURLs );

    public static final VoCacheManager NULL = new VoCacheManager()
    {
        public void drop( Object pUserSessionID )
        {
        }

        public void addType( Object pUserSessionID, CacheID pCacheID, String pViewObjectClassName )
        {
        }

        public void addInstance( Object pUserSessionID, CacheID pCacheID, ObjectURL pObjectURL )
        {
        }

        public CacheID[] invalidate( Object pUserSessionID, List<ObjectURL> pObjectURLs )
        {
            return new CacheID[0];
        }
    };
}