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.hdfs; import org.apache.commons.logging.impl.Log4JLogger; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.CreateFlag; import org.apache.hadoop.fs.FSDataOutputStream; import org.apache.hadoop.fs.FileContext; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.LocatedFileStatus; import org.apache.hadoop.fs.Options; import org.apache.hadoop.fs.Path; import org.apache.hadoop.fs.RemoteIterator; import org.apache.hadoop.fs.permission.FsPermission; import org.apache.log4j.Level; import org.junit.After; import org.junit.AfterClass; import org.junit.BeforeClass; import org.junit.Test; import java.io.IOException; import java.util.EnumSet; import java.util.Random; import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertFalse; import static org.junit.Assert.assertTrue; /** * This class tests the FileStatus API. */ public class TestListFilesInFileContext { { ((Log4JLogger) FileSystem.LOG).getLogger().setLevel(Level.ALL); } static final long seed = 0xDEADBEEFL; final private static Configuration conf = new Configuration(); private static MiniDFSCluster cluster; private static FileContext fc; final private static Path TEST_DIR = new Path("/main_"); final private static int FILE_LEN = 10; final private static Path FILE1 = new Path(TEST_DIR, "file1"); final private static Path DIR1 = new Path(TEST_DIR, "dir1"); final private static Path FILE2 = new Path(DIR1, "file2"); final private static Path FILE3 = new Path(DIR1, "file3"); @BeforeClass public static void testSetUp() throws Exception { cluster = new MiniDFSCluster.Builder(conf).build(); fc = FileContext.getFileContext(cluster.getConfiguration(0)); fc.delete(TEST_DIR, true); } private static void writeFile(FileContext fc, Path name, int fileSize) throws IOException { // Create and write a file that contains three blocks of data FSDataOutputStream stm = fc.create(name, EnumSet.of(CreateFlag.CREATE), Options.CreateOpts.createParent()); byte[] buffer = new byte[fileSize]; Random rand = new Random(seed); rand.nextBytes(buffer); stm.write(buffer); stm.close(); } @AfterClass public static void testShutdown() throws Exception { cluster.shutdown(); } /** * Test when input path is a file */ @Test public void testFile() throws IOException { fc.mkdir(TEST_DIR, FsPermission.getDefault(), true); writeFile(fc, FILE1, FILE_LEN); RemoteIterator<LocatedFileStatus> itor = fc.util().listFiles(FILE1, true); LocatedFileStatus stat = itor.next(); assertFalse(itor.hasNext()); assertTrue(stat.isFile()); assertEquals(FILE_LEN, stat.getLen()); assertEquals(fc.makeQualified(FILE1), stat.getPath()); assertEquals(1, stat.getBlockLocations().length); itor = fc.util().listFiles(FILE1, false); stat = itor.next(); assertFalse(itor.hasNext()); assertTrue(stat.isFile()); assertEquals(FILE_LEN, stat.getLen()); assertEquals(fc.makeQualified(FILE1), stat.getPath()); assertEquals(1, stat.getBlockLocations().length); } @After public void cleanDir() throws IOException { fc.delete(TEST_DIR, true); } /** * Test when input path is a directory */ @Test public void testDirectory() throws IOException { fc.mkdir(DIR1, FsPermission.getDefault(), true); // test empty directory RemoteIterator<LocatedFileStatus> itor = fc.util().listFiles(DIR1, true); assertFalse(itor.hasNext()); itor = fc.util().listFiles(DIR1, false); assertFalse(itor.hasNext()); // testing directory with 1 file writeFile(fc, FILE2, FILE_LEN); itor = fc.util().listFiles(DIR1, true); LocatedFileStatus stat = itor.next(); assertFalse(itor.hasNext()); assertTrue(stat.isFile()); assertEquals(FILE_LEN, stat.getLen()); assertEquals(fc.makeQualified(FILE2), stat.getPath()); assertEquals(1, stat.getBlockLocations().length); itor = fc.util().listFiles(DIR1, false); stat = itor.next(); assertFalse(itor.hasNext()); assertTrue(stat.isFile()); assertEquals(FILE_LEN, stat.getLen()); assertEquals(fc.makeQualified(FILE2), stat.getPath()); assertEquals(1, stat.getBlockLocations().length); // test more complicated directory writeFile(fc, FILE1, FILE_LEN); writeFile(fc, FILE3, FILE_LEN); itor = fc.util().listFiles(TEST_DIR, true); stat = itor.next(); assertTrue(stat.isFile()); assertEquals(fc.makeQualified(FILE2), stat.getPath()); stat = itor.next(); assertTrue(stat.isFile()); assertEquals(fc.makeQualified(FILE3), stat.getPath()); stat = itor.next(); assertTrue(stat.isFile()); assertEquals(fc.makeQualified(FILE1), stat.getPath()); assertFalse(itor.hasNext()); itor = fc.util().listFiles(TEST_DIR, false); stat = itor.next(); assertTrue(stat.isFile()); assertEquals(fc.makeQualified(FILE1), stat.getPath()); assertFalse(itor.hasNext()); } /** * Test when input patch has a symbolic links as its children */ @Test public void testSymbolicLinks() throws IOException { writeFile(fc, FILE1, FILE_LEN); writeFile(fc, FILE2, FILE_LEN); writeFile(fc, FILE3, FILE_LEN); Path dir4 = new Path(TEST_DIR, "dir4"); Path dir5 = new Path(dir4, "dir5"); Path file4 = new Path(dir4, "file4"); fc.createSymlink(DIR1, dir5, true); fc.createSymlink(FILE1, file4, true); RemoteIterator<LocatedFileStatus> itor = fc.util().listFiles(dir4, true); LocatedFileStatus stat = itor.next(); assertTrue(stat.isFile()); assertEquals(fc.makeQualified(FILE2), stat.getPath()); stat = itor.next(); assertTrue(stat.isFile()); assertEquals(fc.makeQualified(FILE3), stat.getPath()); stat = itor.next(); assertTrue(stat.isFile()); assertEquals(fc.makeQualified(FILE1), stat.getPath()); assertFalse(itor.hasNext()); itor = fc.util().listFiles(dir4, false); stat = itor.next(); assertTrue(stat.isFile()); assertEquals(fc.makeQualified(FILE1), stat.getPath()); assertFalse(itor.hasNext()); } }