001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   https://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019
020package org.apache.commons.compress.archivers.zip;
021
022import java.io.IOException;
023import java.nio.file.Files;
024import java.nio.file.Path;
025import java.util.concurrent.atomic.AtomicInteger;
026
027import org.apache.commons.compress.parallel.FileBasedScatterGatherBackingStore;
028import org.apache.commons.compress.parallel.ScatterGatherBackingStore;
029import org.apache.commons.compress.parallel.ScatterGatherBackingStoreSupplier;
030
031/**
032 * Implements {@link ScatterGatherBackingStoreSupplier} using a temporary folder.
033 * <p>
034 * For example:
035 * </p>
036 *
037 * <pre>
038 * final Path dir = Paths.get("target/custom-temp-dir");
039 * Files.createDirectories(dir);
040 * final ParallelScatterZipCreator zipCreator = new ParallelScatterZipCreator(Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors()),
041 *         new DefaultBackingStoreSupplier(dir));
042 * </pre>
043 *
044 * @since 1.23
045 */
046public class DefaultBackingStoreSupplier implements ScatterGatherBackingStoreSupplier {
047
048    private static final String PREFIX = "parallelscatter";
049
050    private final AtomicInteger storeNum = new AtomicInteger();
051
052    private final Path dir;
053
054    /**
055     * Constructs a new instance. If {@code dir} is null, then use the default temporary-file directory.
056     *
057     * @param dir temporary folder, may be null, must exist if non-null.
058     */
059    public DefaultBackingStoreSupplier(final Path dir) {
060        this.dir = dir;
061    }
062
063    @Override
064    public ScatterGatherBackingStore get() throws IOException {
065        final String suffix = "n" + storeNum.incrementAndGet();
066        final Path tempFile = dir == null ? Files.createTempFile(PREFIX, suffix) : Files.createTempFile(dir, PREFIX, suffix);
067        return new FileBasedScatterGatherBackingStore(tempFile);
068    }
069}