Code example for ConcurrentHashMap

Methods: clear

		purgeHandler.postDelayed(purger, DELAY_BEFORE_PURGE);
	private void clearCaches(){ 
	 * @param key In this case the file name (used as the mapping id). 
	 * @return bitmap The cached bitmap or null if it could not be located. 
	 * As the name suggests, this method attemps to obtain a bitmap stored 
	 * in one of the caches. First it checks the hard cache for the key. 
	 * If a key is found, it moves the cached bitmap to the head of the cache 
	 * so it gets moved to the soft cache last. 
	 * If the hard cache doesn't contain the bitmap, it checks the soft cache 
	 * for the cached bitmap. If neither of the caches contain the bitmap, this