| /* |
| * 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.lucene.mockfile; |
| |
| import java.io.IOException; |
| import java.nio.file.DirectoryStream; |
| import java.nio.file.DirectoryStream.Filter; |
| import java.nio.file.FileSystem; |
| import java.nio.file.Path; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Random; |
| |
| /** |
| * Gives an unpredictable, but deterministic order to directory listings. |
| * <p> |
| * This can be useful if for instance, you have build servers on |
| * linux but developers are using macs. |
| */ |
| public class ShuffleFS extends FilterFileSystemProvider { |
| final long seed; |
| |
| /** |
| * Create a new instance, wrapping {@code delegate}. |
| */ |
| public ShuffleFS(FileSystem delegate, long seed) { |
| super("shuffle://", delegate); |
| this.seed = seed; |
| } |
| |
| @Override |
| public DirectoryStream<Path> newDirectoryStream(Path dir, Filter<? super Path> filter) throws IOException { |
| try (DirectoryStream<Path> stream = super.newDirectoryStream(dir, filter)) { |
| // read complete directory listing |
| List<Path> contents = new ArrayList<>(); |
| for (Path path : stream) { |
| contents.add(path); |
| } |
| // sort first based only on filename |
| Collections.sort(contents, (path1, path2) -> path1.getFileName().toString().compareTo(path2.getFileName().toString())); |
| // sort based on current class seed |
| Collections.shuffle(contents, new Random(seed)); |
| return new DirectoryStream<Path>() { |
| @Override |
| public Iterator<Path> iterator() { |
| return contents.iterator(); |
| } |
| @Override |
| public void close() throws IOException {} |
| }; |
| } |
| } |
| } |