/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* 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 Lesser General Public License for more details.
*
* Copyright (c) 2006 - 2013 Pentaho Corporation and Contributors.  All rights reserved.
*/

package org.pentaho.reporting.libraries.resourceloader.cache;

import org.pentaho.reporting.libraries.resourceloader.ResourceData;
import org.pentaho.reporting.libraries.resourceloader.ResourceKey;
import org.pentaho.reporting.libraries.resourceloader.ResourceLoadingException;
import org.pentaho.reporting.libraries.resourceloader.ResourceManager;

import java.lang.ref.Reference;
import java.lang.ref.WeakReference;

/**
 * Disables caching. It simply returns null on every request and ignores the put requests. You certainly want to use one
 * of the other cache providers in real world applications.
 *
 * @author Thomas Morgner
 */
public class NullResourceDataCache implements ResourceDataCache {
  private Reference lastEntry;

  public NullResourceDataCache() {
  }

  public ResourceData put( final ResourceManager caller, final ResourceData data ) throws ResourceLoadingException {
    final ResourceData retval = CachingResourceData.createCached( data );
    lastEntry = new WeakReference( new DefaultResourceDataCacheEntry( retval, caller ) );
    return retval;
  }

  public ResourceDataCacheEntry get( final ResourceKey key ) {
    if ( lastEntry != null ) {
      final ResourceDataCacheEntry entry = (ResourceDataCacheEntry) lastEntry.get();
      if ( entry != null && key.equals( entry.getData().getKey() ) ) {
        return entry;
      }

      lastEntry = null;
    }
    return null;
  }

  public void remove( final ResourceData data ) {
  }

  public void clear() {
    lastEntry = null;
  }

  public void shutdown() {
    lastEntry = null;
  }
}