hyracks/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/file/BufferedFileHandle.java

/*
 * Copyright 2009-2010 by The Regents of the University of California
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * you may obtain a copy of the License from
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package edu.uci.ics.hyracks.storage.common.file;

import java.util.concurrent.atomic.AtomicInteger;

import edu.uci.ics.hyracks.api.io.IFileHandle;

public class BufferedFileHandle {
    private final int fileId;
    private IFileHandle handle;
    private final AtomicInteger refCount;

    public BufferedFileHandle(int fileId, IFileHandle handle) {
        this.fileId = fileId;
        this.handle = handle;
        refCount = new AtomicInteger();
    }

    public int getFileId() {
        return fileId;
    }

    public IFileHandle getFileHandle() {
        return handle;
    }

    public void markAsDeleted() {
        handle = null;
    }

    public boolean fileHasBeenDeleted() {
        return handle == null;
    }

    public int incReferenceCount() {
        return refCount.incrementAndGet();
    }

    public int decReferenceCount() {
        return refCount.decrementAndGet();
    }

    public int getReferenceCount() {
        return refCount.get();
    }

    public long getDiskPageId(int pageId) {
        return getDiskPageId(fileId, pageId);
    }

    public static long getDiskPageId(int fileId, int pageId) {
        return (((long) fileId) << 32) + pageId;
    }

    public static int getFileId(long dpid) {
        return (int) ((dpid >> 32) & 0xffffffff);
    }

    public static int getPageId(long dpid) {
        return (int) (dpid & 0xffffffff);
    }
}