001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.io.file.spi;
019
020import java.net.URI;
021import java.net.URL;
022import java.nio.file.FileSystems;
023import java.nio.file.Path;
024import java.nio.file.spi.FileSystemProvider;
025import java.util.Collections;
026import java.util.List;
027import java.util.Objects;
028
029/**
030 * Helps to work with {@link FileSystemProvider}.
031 *
032 * @since 2.9.0
033 */
034public class FileSystemProviders { // NOPMD Class will be final in 3.0.
035
036    private static final FileSystemProviders INSTALLED = new FileSystemProviders(FileSystemProvider.installedProviders());
037
038    /**
039     * Gets the {@link FileSystemProvider} for the given Path.
040     *
041     * @param path The Path to query
042     * @return the {@link FileSystemProvider} for the given Path.
043     */
044    @SuppressWarnings("resource") // FileSystem is not allocated here.
045    public static FileSystemProvider getFileSystemProvider(final Path path) {
046        return Objects.requireNonNull(path, "path").getFileSystem().provider();
047    }
048
049    /**
050     * Returns the instance for the installed providers.
051     *
052     * @return the instance for the installed providers.
053     * @see FileSystemProvider#installedProviders()
054     */
055    public static FileSystemProviders installed() {
056        return INSTALLED;
057    }
058
059    private final List<FileSystemProvider> providers;
060
061    /*
062     * Might make public later.
063     */
064    private FileSystemProviders(final List<FileSystemProvider> providers) {
065        this.providers = providers != null ? providers : Collections.emptyList();
066    }
067
068    /**
069     * Gets the {@link FileSystemProvider} for the given scheme.
070     *
071     * @param scheme The scheme to query.
072     * @return the {@link FileSystemProvider} for the given URI or null.
073     */
074    @SuppressWarnings("resource") // FileSystems.getDefault() returns a constant.
075    public FileSystemProvider getFileSystemProvider(final String scheme) {
076        Objects.requireNonNull(scheme, "scheme");
077        // Check default provider first to avoid loading of installed providers.
078        if (scheme.equalsIgnoreCase("file")) {
079            return FileSystems.getDefault().provider();
080        }
081        // Find provider.
082        return providers.stream().filter(provider -> provider.getScheme().equalsIgnoreCase(scheme)).findFirst().orElse(null);
083    }
084
085    /**
086     * Gets the {@link FileSystemProvider} for the given URI.
087     *
088     * @param uri The URI to query
089     * @return the {@link FileSystemProvider} for the given URI or null.
090     */
091    public FileSystemProvider getFileSystemProvider(final URI uri) {
092        return getFileSystemProvider(Objects.requireNonNull(uri, "uri").getScheme());
093    }
094
095    /**
096     * Gets the {@link FileSystemProvider} for the given URL.
097     *
098     * @param url The URL to query
099     * @return the {@link FileSystemProvider} for the given URI or null.
100     */
101    public FileSystemProvider getFileSystemProvider(final URL url) {
102        return getFileSystemProvider(Objects.requireNonNull(url, "url").getProtocol());
103    }
104
105}