/*
 * Copyright (C) 2005-2009 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.dictionary.constraint;

import java.util.HashMap;
import java.util.Map;

import org.alfresco.service.cmr.dictionary.Constraint;

/**
 * A registry of constraints. 
 * 
 * @author Derek Hulley
 * @since 3.2
 */
public class ConstraintRegistry
{
    private static ConstraintRegistry instance = new ConstraintRegistry();
    
    private Map<String, Constraint> constraints;

    /**
     * @return      Returns the singleton
     */
    public static ConstraintRegistry getInstance()
    {
        return instance;
    }

    /**
     * Private constructor
     * @see #getInstance()
     */
    private ConstraintRegistry()
    {
        constraints = new HashMap<String, Constraint>(13);
    }
    
    /**
     * Register the constraint by name
     */
    public void register(String name, Constraint constraint)
    {
        if (this == instance)
        {
            constraints.put(name, constraint);
        }
        else
        {
            instance.register(name, constraint);
        }
    }
    
    /**
     * Get the constraint by name
     * 
     * @param name          the name by which the constraint was registered
     * @return              Returns the constraint or <tt>null</tt> if it does not exist.
     */
    public Constraint getConstraint(String name)
    {
        if (this == instance)
        {
            return constraints.get(name);
        }
        else
        {
            return instance.getConstraint(name);
        }
    }
}