/* ======================================================================
The Bodington System Software License, Version 1.0
 
Copyright (c) 2001 The University of Leeds.  All rights reserved.
 
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
 
1.  Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
 
2.  Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
 
3.  The end-user documentation included with the redistribution, if any,
must include the following acknowledgement:  "This product includes
software developed by the University of Leeds
(http://www.bodington.org/)."  Alternately, this acknowledgement may
appear in the software itself, if and wherever such third-party
acknowledgements normally appear.
 
4.  The names "Bodington", "Nathan Bodington", "Bodington System",
"Bodington Open Source Project", and "The University of Leeds" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
d.gardner@leeds.ac.uk.
 
5.  The name "Bodington" may not appear in the name of products derived
from this software without prior written permission of the University of
Leeds.
 
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO,  TITLE,  THE IMPLIED WARRANTIES
OF QUALITY  AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
EVENT SHALL THE UNIVERSITY OF LEEDS OR ITS CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
=========================================================
 
This software was originally created by the University of Leeds and may contain voluntary
contributions from others.  For more information on the Bodington Open Source Project, please
see http://bodington.org/
 
====================================================================== */
package org.bodington.server.resources;

import org.bodington.database.IndexKey;
import org.bodington.database.PrimaryKey;
import org.bodington.sqldatabase.SqlDatabase;

/**
 * Class so that we can do index lookups on the parent resource and
 * the name of the child. This should mean that a resource doesn't have to 
 * load all it's children to find one of them.
 * @author buckett
 */
public class ResourceParentIndexKey implements IndexKey
{
    
    private PrimaryKey parent;
    private String child;
    private int hash = 0;

    public ResourceParentIndexKey ()
    {}
    
    public ResourceParentIndexKey (PrimaryKey parent, String child)
    {
        setParent(parent);
        setChild(child);
    }
    
    public void setParent(PrimaryKey parent)
    {
        this.parent = parent;
        this.hash = 0;
    }
    
    public void setChild (String child)
    {
        this.child = child;
        this.hash = 0;
    }
    
    public String whereClause()
    {
        if (parent == null)
            return "parent_resource_id IS NULL AND name = "+ SqlDatabase.quotedSQL(child);
        else
            return "parent_resource_id = "+ parent+ " AND name = "+ SqlDatabase.quotedSQL(child);
    }

    /**
     * We want to cache <code>nulls</code> so that lookups for files in 
     * resources are cached.
     */
    public boolean cacheNull()
    {
        return true;
    }
    
    public int hashCode()
    {
        if (hash == 0)
        {
            if (parent == null)
                hash = child.hashCode();
            else
                hash = parent.intValue() ^ child.hashCode();
        }
        return hash;
    }
    
    public boolean equals (Object other)
    {
        if (other instanceof ResourceParentIndexKey)
        {
            ResourceParentIndexKey otherIndex = (ResourceParentIndexKey)other;
            boolean sameChild = this.child.equals(otherIndex.child);
            boolean sameParent = (this.parent != null &&
                otherIndex.parent != null && this.parent.equals(otherIndex.parent))
                ||
                (this.parent == null && otherIndex.parent == null);
            return sameChild && sameParent;
        }
        return false;
    }
    
    public String toString ()
    {
        return "Parent: "+ parent+ ", Child: "+ child;
    }

}