/*
 * Copyright (C) 2005-2010 Alfresco Software Limited.
 *
 * This file is part of Alfresco
 *
 * Alfresco is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Alfresco 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 Alfresco. If not, see <http://www.gnu.org/licenses/>. */

package org.alfresco.repo.avm;

import java.io.Serializable;

/**
 * Holds a ancestor-descendent relationship.
 * @author britt
 */
public class HistoryLinkImpl implements HistoryLink, Serializable
{
    private static final long serialVersionUID = -430859344980137718L;

    /**
     * The ancestor.
     */
    private AVMNode fAncestor;
    
    /**
     * The descendent.
     */
    private AVMNode fDescendent;
    
    /**
     * Set the ancestor part of this.
     * @param ancestor
     */
    public void setAncestor(AVMNode ancestor)
    {
        fAncestor = ancestor;
    }

    /**
     * Get the ancestor part of this.
     * @return The ancestor.
     */
    public AVMNode getAncestor()
    {
        return fAncestor;
    }

    /**
     * Set the descendent part of this.
     * @param descendent
     */
    public void setDescendent(AVMNode descendent)
    {
        fDescendent = descendent;
    }

    /**
     * Get the descendent part of this.
     * @return The descendent.
     */
    public AVMNode getDescendent()
    {
        return fDescendent;
    }

    /**
     * Equals override.
     * @param obj
     * @return Equality.
     */
    @Override
    public boolean equals(Object obj)
    {
        if (this == obj)
        {
            return true;
        }
        if (!(obj instanceof HistoryLink))
        {
            return false;
        }
        HistoryLink o = (HistoryLink)obj;
        return fAncestor.equals(o.getAncestor()) && fDescendent.equals(o.getDescendent());
    }

    /**
     * Get the hashcode.
     * @return The hashcode.
     */
    @Override
    public int hashCode()
    {
        return fAncestor.hashCode() + fDescendent.hashCode();
    }
}