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.apex.malhar.lib.utils; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.File; import java.io.IOException; import java.util.EnumSet; import java.util.Random; import org.junit.Assert; import org.junit.Test; import org.apache.commons.io.FileUtils; import org.apache.hadoop.fs.CreateFlag; import org.apache.hadoop.fs.FileContext; import org.apache.hadoop.fs.Options; import org.apache.hadoop.fs.Path; public class IOUtilsTest { @Test public void testCopyPartial() throws IOException { testCopyPartialHelper(1024, 0, 512); } @Test public void testCopyPartialLarge() throws IOException { testCopyPartialHelper(2048, 0, 1068); } @Test public void testCopyFromOffset() throws IOException { testCopyPartialHelper(2048, 1024, 1024); } private void testCopyPartialHelper(int dataSize, int offset, long size) throws IOException { FileUtils.deleteQuietly(new File("target/IOUtilsTest")); File file = new File("target/IOUtilsTest/testCopyPartial/input"); createDataFile(file, dataSize); FileContext fileContext = FileContext.getFileContext(); DataInputStream inputStream = fileContext.open(new Path(file.getAbsolutePath())); Path output = new Path("target/IOUtilsTest/testCopyPartial/output"); DataOutputStream outputStream = fileContext.create(output, EnumSet.of(CreateFlag.CREATE, CreateFlag.OVERWRITE), Options.CreateOpts.CreateParent.createParent()); if (offset == 0) { IOUtils.copyPartial(inputStream, size, outputStream); } else { IOUtils.copyPartial(inputStream, offset, size, outputStream); } outputStream.close(); Assert.assertTrue("output exists", fileContext.util().exists(output)); Assert.assertEquals("output size", size, fileContext.getFileStatus(output).getLen()); // FileUtils.deleteQuietly(new File("target/IOUtilsTest")); } private void createDataFile(File file, int dataSize) throws IOException { byte[] val = new byte[dataSize]; Random random = new Random(); random.nextBytes(val); FileUtils.write(file, new String(val)); } }