Set<Entry<ReferencedEnvelope, Tile>> entrySet = cachedTiles.entrySet();
for( Entry<ReferencedEnvelope, Tile> set : entrySet ) {
Tile tile = set.getValue();
// only dispose the image if this tile is not in the ready tiles
if (!readyTiles.containsValue(tile)) {
tile.disposeSWTImage();
}
}
cachedTiles.clear();
}