TileSet.java

/*
 * Copyright 2012 Hannes Janetzek
 *
 * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
 *
 * This program is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.oscim.layers.tile;

import java.util.Arrays;
import java.util.Comparator;

/**
 * TileSet for use with TileManager.getActiveTiles(TileSet) to get the current
 * tiles. Tiles will locked and not be modifed until getActiveTiles passes them
 * back to TileManager on a second invocation or TileManager.releaseTiles().
 */
public final class TileSet {
	public int cnt = 0;
	public MapTile[] tiles;

	/** update counter will be set by getActiveTiles when TileSet has changed */
	int serial;

	public TileSet() {
		tiles = new MapTile[1];
	}

	public TileSet(int numTiles) {
		tiles = new MapTile[numTiles];
	}

	public MapTile getTile(int x, int y) {
		for (int i = 0; i < cnt; i++)
			if (tiles[i].tileX == x && tiles[i].tileY == y)
				return tiles[i];

		return null;
	}

	/**
	 * Locked tiles to ensure that they are not released from cache.
	 * Call releaseTiles() when tiles are not needed any longer.
	 */
	public void lockTiles() {
		synchronized (TileSet.class) {
			for (int i = 0; i < cnt; i++)
				tiles[i].lock();
		}
	}

	/**
	 * Release locked tiles.
	 */
	public void releaseTiles() {
		synchronized (TileSet.class) {
			for (int i = 0; i < cnt; i++)
				tiles[i].unlock();
		}
		Arrays.fill(tiles, null);
		cnt = 0;
		serial = 0;
	}

	/**
	 * Clone TileSet from source. Release previous tiles and lock
	 * new tiles.
	 */
	public void setTiles(TileSet source) {
		/* lock tiles (and their proxies) to not be removed from cache */
		source.lockTiles();

		/* unlock previous tiles */
		releaseTiles();

		if (source.tiles.length != tiles.length) {
			tiles = new MapTile[source.tiles.length];
		}

		System.arraycopy(source.tiles, 0, tiles, 0, source.cnt);

		cnt = source.cnt;
	}

	public static Comparator<MapTile> coordComparator = new CoordComparator();

	public static class CoordComparator implements Comparator<MapTile> {

		@Override
		public int compare(MapTile lhs, MapTile rhs) {
			if (lhs.tileX == rhs.tileX) {
				if (lhs.tileY == rhs.tileY)
					return 0;

				if (lhs.tileY < rhs.tileY)
					return 1;

				return -1;
			}
			if (lhs.tileX < rhs.tileX)
				return 1;

			return -1;
		}
	}

	public boolean contains(MapTile t) {
		for (int i = 0; i < cnt; i++)
			if (tiles[i].equals(t))
				return true;

		return false;
	}
}