Java tutorial
/** * 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.hadoop.fs; import java.io.IOException; import java.util.HashSet; import java.util.Random; import java.util.Set; import org.apache.commons.logging.impl.Log4JLogger; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FSDataOutputStream; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.log4j.Level; import static org.junit.Assert.*; import org.junit.Test; import org.junit.BeforeClass; /** * This class tests the FileStatus API. */ public class TestListFiles { { ((Log4JLogger) FileSystem.LOG).getLogger().setLevel(Level.ALL); } static final long seed = 0xDEADBEEFL; final protected static Configuration conf = new Configuration(); protected static FileSystem fs; protected static Path TEST_DIR; final private static int FILE_LEN = 10; private static Path FILE1; private static Path DIR1; private static Path FILE2; private static Path FILE3; static { setTestPaths(new Path(System.getProperty("test.build.data", "build/test/data/work-dir/localfs"), "main_")); } protected static Path getTestDir() { return TEST_DIR; } /** * Sets the root testing directory and reinitializes any additional test paths * that are under the root. This method is intended to be called from a * subclass's @BeforeClass method if there is a need to override the testing * directory. * * @param testDir Path root testing directory */ protected static void setTestPaths(Path testDir) { TEST_DIR = testDir; FILE1 = new Path(TEST_DIR, "file1"); DIR1 = new Path(TEST_DIR, "dir1"); FILE2 = new Path(DIR1, "file2"); FILE3 = new Path(DIR1, "file3"); } @BeforeClass public static void testSetUp() throws Exception { fs = FileSystem.getLocal(conf); fs.delete(TEST_DIR, true); } private static void writeFile(FileSystem fileSys, Path name, int fileSize) throws IOException { // Create and write a file that contains three blocks of data FSDataOutputStream stm = fileSys.create(name); byte[] buffer = new byte[fileSize]; Random rand = new Random(seed); rand.nextBytes(buffer); stm.write(buffer); stm.close(); } /** Test when input path is a file */ @Test public void testFile() throws IOException { fs.mkdirs(TEST_DIR); writeFile(fs, FILE1, FILE_LEN); RemoteIterator<LocatedFileStatus> itor = fs.listFiles(FILE1, true); LocatedFileStatus stat = itor.next(); assertFalse(itor.hasNext()); assertTrue(stat.isFile()); assertEquals(FILE_LEN, stat.getLen()); assertEquals(fs.makeQualified(FILE1), stat.getPath()); assertEquals(1, stat.getBlockLocations().length); itor = fs.listFiles(FILE1, false); stat = itor.next(); assertFalse(itor.hasNext()); assertTrue(stat.isFile()); assertEquals(FILE_LEN, stat.getLen()); assertEquals(fs.makeQualified(FILE1), stat.getPath()); assertEquals(1, stat.getBlockLocations().length); fs.delete(FILE1, true); } /** Test when input path is a directory */ @Test public void testDirectory() throws IOException { fs.mkdirs(DIR1); // test empty directory RemoteIterator<LocatedFileStatus> itor = fs.listFiles(DIR1, true); assertFalse(itor.hasNext()); itor = fs.listFiles(DIR1, false); assertFalse(itor.hasNext()); // testing directory with 1 file writeFile(fs, FILE2, FILE_LEN); itor = fs.listFiles(DIR1, true); LocatedFileStatus stat = itor.next(); assertFalse(itor.hasNext()); assertTrue(stat.isFile()); assertEquals(FILE_LEN, stat.getLen()); assertEquals(fs.makeQualified(FILE2), stat.getPath()); assertEquals(1, stat.getBlockLocations().length); itor = fs.listFiles(DIR1, false); stat = itor.next(); assertFalse(itor.hasNext()); assertTrue(stat.isFile()); assertEquals(FILE_LEN, stat.getLen()); assertEquals(fs.makeQualified(FILE2), stat.getPath()); assertEquals(1, stat.getBlockLocations().length); // test more complicated directory writeFile(fs, FILE1, FILE_LEN); writeFile(fs, FILE3, FILE_LEN); Set<Path> filesToFind = new HashSet<Path>(); filesToFind.add(fs.makeQualified(FILE1)); filesToFind.add(fs.makeQualified(FILE2)); filesToFind.add(fs.makeQualified(FILE3)); itor = fs.listFiles(TEST_DIR, true); stat = itor.next(); assertTrue(stat.isFile()); assertTrue("Path " + stat.getPath() + " unexpected", filesToFind.remove(stat.getPath())); stat = itor.next(); assertTrue(stat.isFile()); assertTrue("Path " + stat.getPath() + " unexpected", filesToFind.remove(stat.getPath())); stat = itor.next(); assertTrue(stat.isFile()); assertTrue("Path " + stat.getPath() + " unexpected", filesToFind.remove(stat.getPath())); assertFalse(itor.hasNext()); assertTrue(filesToFind.isEmpty()); itor = fs.listFiles(TEST_DIR, false); stat = itor.next(); assertTrue(stat.isFile()); assertEquals(fs.makeQualified(FILE1), stat.getPath()); assertFalse(itor.hasNext()); fs.delete(TEST_DIR, true); } }