org.sourcepit.common.utils.zip.EntrySizeBasedZipPartitioner.java Source code

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Here is the source code for org.sourcepit.common.utils.zip.EntrySizeBasedZipPartitioner.java

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/*
 * Copyright 2014 Bernd Vogt and others.
 * 
 * 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 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.sourcepit.common.utils.zip;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.TreeMap;
import java.util.concurrent.Callable;
import java.util.zip.ZipEntry;
import java.util.zip.ZipException;
import java.util.zip.ZipInputStream;

import org.apache.commons.io.IOUtils;

public class EntrySizeBasedZipPartitioner implements ZipPartitioner {
    public Collection<Callable<Integer>> computePartitions(ZipInputStreamFactory streamFactory,
            ZipEntryHandler entryHandler, int nrOfThreads) throws IOException {
        List<Set<Integer>> workScopes = new ArrayList<Set<Integer>>();

        for (int i = 0; i < nrOfThreads; i++) {
            workScopes.add(new HashSet<Integer>());
        }

        TreeMap<ZipEntry, Integer> zipEntryNames = getZipEntryNames(streamFactory);

        Collection<Integer> workIndices = zipEntryNames.values();

        int idx = 0;
        for (Integer integer : workIndices) {
            workScopes.get(idx).add(integer);
            idx = idx < nrOfThreads - 1 ? idx + 1 : 0;
        }

        final Collection<Callable<Integer>> tasks = new ArrayList<Callable<Integer>>();
        for (Set<Integer> work : workScopes) {
            IndexBasedZipPartitionProcessor task = new IndexBasedZipPartitionProcessor(streamFactory, entryHandler,
                    work);
            tasks.add(task);
        }
        return tasks;
    }

    private TreeMap<ZipEntry, Integer> getZipEntryNames(ZipInputStreamFactory streamFactory)
            throws ZipException, IOException {
        final TreeMap<ZipEntry, Integer> entryToIndex = new TreeMap<ZipEntry, Integer>(new Comparator<ZipEntry>() {
            public int compare(ZipEntry ze1, ZipEntry ze2) {
                long s1 = ze1.getSize();
                long s2 = ze2.getSize();
                int r = (int) -(s1 - s2);
                return r == 0 ? -1 : r;
            }
        });

        final ZipInputStream zipStream = streamFactory.newZipInputStream();
        try {
            int idx = 0;
            ZipEntry zipEntry = zipStream.getNextEntry();
            while (zipEntry != null) {
                entryToIndex.put(zipEntry, Integer.valueOf(idx));
                zipEntry = zipStream.getNextEntry();
                idx++;
            }
        } finally {
            IOUtils.closeQuietly(zipStream);
        }

        return entryToIndex;
    }
}