org.apache.solr.util.SolrFileCleaningTracker.java Source code

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Here is the source code for org.apache.solr.util.SolrFileCleaningTracker.java

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/*
 * 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.solr.util;

import java.io.File;
import java.lang.ref.PhantomReference;
import java.lang.ref.ReferenceQueue;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;

import org.apache.commons.io.FileCleaningTracker;
import org.apache.commons.io.FileDeleteStrategy;

public class SolrFileCleaningTracker extends FileCleaningTracker {

    ReferenceQueue<Object> q = new ReferenceQueue<>();

    final Collection<Tracker> trackers = Collections.synchronizedSet(new HashSet<Tracker>());

    final List<String> deleteFailures = Collections.synchronizedList(new ArrayList<String>());

    volatile boolean exitWhenFinished = false;

    Thread reaper;

    public void track(final File file, final Object marker) {
        track(file, marker, null);
    }

    public void track(final File file, final Object marker, final FileDeleteStrategy deleteStrategy) {
        if (file == null) {
            throw new NullPointerException("The file must not be null");
        }
        addTracker(file.getPath(), marker, deleteStrategy);
    }

    public void track(final String path, final Object marker) {
        track(path, marker, null);
    }

    public void track(final String path, final Object marker, final FileDeleteStrategy deleteStrategy) {
        if (path == null) {
            throw new NullPointerException("The path must not be null");
        }
        addTracker(path, marker, deleteStrategy);
    }

    private synchronized void addTracker(final String path, final Object marker,
            final FileDeleteStrategy deleteStrategy) {
        if (exitWhenFinished) {
            throw new IllegalStateException("No new trackers can be added once exitWhenFinished() is called");
        }
        if (reaper == null) {
            reaper = new Reaper();
            reaper.start();
        }
        trackers.add(new Tracker(path, deleteStrategy, marker, q));
    }

    public int getTrackCount() {
        return trackers.size();
    }

    public List<String> getDeleteFailures() {
        return deleteFailures;
    }

    public synchronized void exitWhenFinished() {
        // synchronized block protects reaper
        exitWhenFinished = true;
        if (reaper != null) {
            synchronized (reaper) {
                reaper.interrupt();
                try {
                    reaper.join();
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                }
            }
        }
    }

    private final class Reaper extends Thread {
        Reaper() {
            super("MultiPart Upload Tmp File Reaper");
            setDaemon(true);
        }

        @Override
        public void run() {
            while (exitWhenFinished == false || trackers.size() > 0) {
                try {
                    // Wait for a tracker to remove.
                    final Tracker tracker = (Tracker) q.remove(); // cannot return null
                    trackers.remove(tracker);
                    if (!tracker.delete()) {
                        deleteFailures.add(tracker.getPath());
                    }
                    tracker.clear();
                } catch (final InterruptedException e) {
                    Thread.currentThread().interrupt();
                    break;
                }
            }
        }
    }

    private static final class Tracker extends PhantomReference<Object> {

        private final String path;

        private final FileDeleteStrategy deleteStrategy;

        Tracker(final String path, final FileDeleteStrategy deleteStrategy, final Object marker,
                final ReferenceQueue<? super Object> queue) {
            super(marker, queue);
            this.path = path;
            this.deleteStrategy = deleteStrategy == null ? FileDeleteStrategy.NORMAL : deleteStrategy;
        }

        public String getPath() {
            return path;
        }

        public boolean delete() {
            return deleteStrategy.deleteQuietly(new File(path));
        }
    }

}