//
// CacheEvent.java
//

/*
OME Bio-Formats package for reading and converting biological file formats.
Copyright (C) 2005-@year@ UW-Madison LOCI and Glencoe Software, Inc.

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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

package loci.formats.cache;

import java.lang.reflect.Field;

/**
 * A event indicating a cache update.
 *
 * <dl><dt><b>Source code:</b></dt>
 * <dd><a href="http://trac.openmicroscopy.org.uk/ome/browser/bioformats.git/components/bio-formats/src/loci/formats/cache/CacheEvent.java">Trac</a>,
 * <a href="http://git.openmicroscopy.org/?p=bioformats.git;a=blob;f=components/bio-formats/src/loci/formats/cache/CacheEvent.java;hb=HEAD">Gitweb</a></dd></dl>
 */
public class CacheEvent {

  // -- Constants --

  /** Event type indicating a new cache source. */
  public static final int SOURCE_CHANGED = 1;

  /** Event type indicating a new cache strategy. */
  public static final int STRATEGY_CHANGED = 2;

  /** Event type indicating an updated current dimensional position. */
  public static final int POSITION_CHANGED = 3;

  /** Event type indicating new axis priorities. */
  public static final int PRIORITIES_CHANGED = 4;

  /** Event type indicating new planar ordering. */
  public static final int ORDER_CHANGED = 5;

  /** Event type indicating new planar ordering. */
  public static final int RANGE_CHANGED = 6;

  /** Event type indicating an object has been added to the cache. */
  public static final int OBJECT_LOADED = 7;

  /** Event type indicating an object has been removed from the cache. */
  public static final int OBJECT_DROPPED = 8;

  // -- Fields --

  /** Source of the cache update. */
  protected Object source;

  /** Type of cache event. */
  protected int type;

  /** Relevant index to the event, if any. */
  protected int index;

  // -- Constructor --

  /** Constructs a cache event. */
  public CacheEvent(Object source, int type) { this(source, type, -1); }

  /** Constructs a cache event. */
  public CacheEvent(Object source, int type, int index) {
    this.source = source;
    this.type = type;
    this.index = index;
  }

  // -- CacheEvent API methods --

  /** Gets the source of the cache update. */
  public Object getSource() { return source; }

  /** Gets the type of cache update. */
  public int getType() { return type; }

  /**
   * Gets the index relevant to the cache update, if any.
   * This parameter is only set for events POSITION_CHANGED,
   * OBJECT_LOADED and OBJECT_DROPPED.
   */
  public int getIndex() { return index; }

  // -- Object API methods --

  public String toString() {
    // scan public fields to determine type name
    String sType = "unknown";
    Field[] fields = getClass().getFields();
    for (int i=0; i<fields.length; i++) {
      try {
        if (fields[i].getInt(null) == type) sType = fields[i].getName();
      }
      catch (IllegalAccessException exc) { }
      catch (IllegalArgumentException exc) { }
    }
    return super.toString() +
      ": source=[" + source + "] type=" + sType + " index=" + index;
  }

}