/*
 * Copyright (c) 2007 BUSINESS OBJECTS SOFTWARE LIMITED
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *  
 *     * 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.
 *  
 *     * Neither the name of Business Objects nor the names of its contributors
 *       may be used to endorse or promote products derived from this software
 *       without specific prior written permission.
 *  
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 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.
 */


/*
 * GemManager.java
 * Created: 25-Mar-2004
 * By: Rick Cameron
 */

package org.openquark.samples.bam;

import java.util.Collection;
import java.util.Locale;

import org.openquark.cal.services.BasicCALServices;
import org.openquark.cal.services.GemEntity;
import org.openquark.cal.services.LocaleUtilities;



/**
 * This is the base GemManager. It provides functionality for caching the
 * available gems, and clearing the cache when the metadata associated with
 * gems is updated.
 */
public abstract class GemManager {

    protected final BasicCALServices calServices;

    private Collection<GemEntity> availableGems;


    /**
     * @return the locale to use for accessing metadata.
     */
    public static Locale getLocaleForMetadata() {
        return LocaleUtilities.INVARIANT_LOCALE;
    }
    
    /**
     * Constructor GemManager
     * 
     * @param calServices
     */
    GemManager (final BasicCALServices calServices) {
        this.calServices = calServices;
    }

    /**
     * Method getAvailableGems
     * 
     * @return Returns a Collection of suitable GemEntities
     */
    public Collection<GemEntity> getAvailableGems () {
        if (availableGems == null) {
            availableGems = calcAvailableGems ();
        }
        
        return availableGems;
    }
    
    /**
     * Method resetAvailableGems
     * 
     * Resets the list of suitable gems. This should be called if changes are made to metadata that may affect the suitability of gems.
     */
    public void resetAvailableGems () {
        availableGems = null;
    }

    /**
     * Method calcAvailableGems
     * 
     * @return Returns the Collection of available gems
     */
    protected abstract Collection<GemEntity> calcAvailableGems ();
    
    protected BasicCALServices getCalServices () {
        return calServices;
    }
}