/*
* 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;

/**
 * A simple resource with only a single dependency.
 *
 * @author Thomas Morgner
 */
public class SimpleResource implements Resource {
  private Object value;
  private ResourceKey key;
  private long version;
  private static final long serialVersionUID = -6007941678785921339L;
  private Class targetType;

  public SimpleResource( final ResourceKey key,
                         final Object value,
                         final Class targetType,
                         final long version ) {
    if ( key == null ) {
      throw new NullPointerException();
    }
    if ( value == null ) {
      throw new NullPointerException();
    }
    if ( targetType == null ) {
      throw new NullPointerException();
    }

    this.targetType = targetType;
    this.value = value;
    this.key = key;
    this.version = version;
  }

  public Object getResource() {
    return value;
  }

  public long getVersion( final ResourceKey key ) {
    if ( key.equals( this.key ) ) {
      return version;
    }
    // -1 is the placeholder for: not known.
    return -1;
  }

  /**
   * The primary source is also included in this set. The dependencies are given as ResourceKey objects. The keys itself
   * do not hold any state information.
   * <p/>
   * The dependencies do not track deep dependencies. So if Resource A depends on Resource B which depends on Resource
   * C, then A only knows about B, not C.
   *
   * @return
   */
  public ResourceKey[] getDependencies() {
    return new ResourceKey[] { getSource() };
  }

  public ResourceKey getSource() {
    return key;
  }

  public Class getTargetType() {
    return targetType;
  }

  public boolean isTemporaryResult() {
    return false;
  }
}