lock = new ReentrantReadWriteLock(file.getName());
	public BFile(File file, int btreeBuffers, int dataBuffers) {		super(file, btreeBuffers);		fileHeader = (BFileHeader) getFileHeader();		//		pages = new LRUPageBuffer(dataBuffers);		if(dataBuffers > 0)			pages = new ClockPageBuffer(dataBuffers);		minFree = PAGE_MIN_FREE;		lock = new ReentrantReadWriteLock(file.getName());	}