| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 at |
| * |
| * 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 org.apache.hadoop.mapred; |
| |
| import java.io.IOException; |
| import java.util.concurrent.LinkedBlockingQueue; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| import org.apache.hadoop.fs.FileSystem; |
| import org.apache.hadoop.fs.Path; |
| |
| class CleanupQueue { |
| |
| public static final Log LOG = |
| LogFactory.getLog(CleanupQueue.class); |
| |
| private static PathCleanupThread cleanupThread; |
| |
| /** |
| * Create a singleton path-clean-up queue. It can be used to delete |
| * paths(directories/files) in a separate thread. This constructor creates a |
| * clean-up thread and also starts it as a daemon. Callers can instantiate one |
| * CleanupQueue per JVM and can use it for deleting paths. Use |
| * {@link CleanupQueue#addToQueue(PathDeletionContext...)} to add paths for |
| * deletion. |
| */ |
| public CleanupQueue() { |
| synchronized (PathCleanupThread.class) { |
| if (cleanupThread == null) { |
| cleanupThread = new PathCleanupThread(); |
| } |
| } |
| } |
| |
| /** |
| * Contains info related to the path of the file/dir to be deleted |
| */ |
| static class PathDeletionContext { |
| String fullPath;// full path of file or dir |
| FileSystem fs; |
| |
| public PathDeletionContext(FileSystem fs, String fullPath) { |
| this.fs = fs; |
| this.fullPath = fullPath; |
| } |
| |
| protected String getPathForCleanup() { |
| return fullPath; |
| } |
| |
| /** |
| * Makes the path(and its subdirectories recursively) fully deletable |
| */ |
| protected void enablePathForCleanup() throws IOException { |
| // Do nothing by default. |
| // Subclasses can override to provide enabling for deletion. |
| } |
| } |
| |
| /** |
| * Adds the paths to the queue of paths to be deleted by cleanupThread. |
| */ |
| void addToQueue(PathDeletionContext... contexts) { |
| cleanupThread.addToQueue(contexts); |
| } |
| |
| protected static boolean deletePath(PathDeletionContext context) |
| throws IOException { |
| context.enablePathForCleanup(); |
| |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Trying to delete " + context.fullPath); |
| } |
| if (context.fs.exists(new Path(context.fullPath))) { |
| return context.fs.delete(new Path(context.fullPath), true); |
| } |
| return true; |
| } |
| |
| // currently used by tests only |
| protected boolean isQueueEmpty() { |
| return (cleanupThread.queue.size() == 0); |
| } |
| |
| private static class PathCleanupThread extends Thread { |
| |
| // cleanup queue which deletes files/directories of the paths queued up. |
| private LinkedBlockingQueue<PathDeletionContext> queue = |
| new LinkedBlockingQueue<PathDeletionContext>(); |
| |
| public PathCleanupThread() { |
| setName("Directory/File cleanup thread"); |
| setDaemon(true); |
| start(); |
| } |
| |
| void addToQueue(PathDeletionContext[] contexts) { |
| for (PathDeletionContext context : contexts) { |
| try { |
| queue.put(context); |
| } catch(InterruptedException ie) {} |
| } |
| } |
| |
| public void run() { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug(getName() + " started."); |
| } |
| PathDeletionContext context = null; |
| while (true) { |
| try { |
| context = queue.take(); |
| // delete the path. |
| if (!deletePath(context)) { |
| LOG.warn("CleanupThread:Unable to delete path " + context.fullPath); |
| } |
| else if (LOG.isDebugEnabled()) { |
| LOG.debug("DELETED " + context.fullPath); |
| } |
| } catch (InterruptedException t) { |
| LOG.warn("Interrupted deletion of " + context.fullPath); |
| return; |
| } catch (Exception e) { |
| LOG.warn("Error deleting path " + context.fullPath + ": " + e); |
| } |
| } |
| } |
| } |
| } |