    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}