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.jena.hadoop.rdf.io.output; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.util.Iterator; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.LocatedFileStatus; import org.apache.hadoop.fs.Path; import org.apache.hadoop.fs.RemoteIterator; import org.apache.hadoop.io.NullWritable; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.JobContext; import org.apache.hadoop.mapreduce.OutputFormat; import org.apache.hadoop.mapreduce.RecordWriter; import org.apache.hadoop.mapreduce.TaskAttemptContext; import org.apache.hadoop.mapreduce.TaskAttemptID; import org.apache.hadoop.mapreduce.TaskType; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.mapreduce.task.JobContextImpl; import org.apache.hadoop.mapreduce.task.TaskAttemptContextImpl; import org.apache.jena.hadoop.rdf.types.AbstractNodeTupleWritable; import org.apache.jena.riot.Lang; import org.apache.jena.riot.RDFDataMgr; import org.apache.jena.riot.lang.StreamRDFCounting; import org.apache.jena.riot.system.StreamRDFLib; import org.junit.Assert; import org.junit.Rule; import org.junit.Test; import org.junit.rules.TemporaryFolder; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Abstract node tuple output format tests * * * @param <TValue> * Tuple type * @param <T> * Writable tuple type * */ public abstract class AbstractNodeTupleOutputFormatTests<TValue, T extends AbstractNodeTupleWritable<TValue>> { private static final Logger LOG = LoggerFactory.getLogger(AbstractNodeTupleOutputFormatTests.class); protected static final int EMPTY_SIZE = 0, SMALL_SIZE = 100, LARGE_SIZE = 10000, VERY_LARGE_SIZE = 100000; /** * Temporary folder for the tests */ @Rule public TemporaryFolder folder = new TemporaryFolder(); /** * Prepares a fresh configuration * * @return Configuration */ protected Configuration prepareConfiguration() { Configuration config = new Configuration(true); // Nothing else to do return config; } /** * Gets the extra file extension to add to the filenames * * @return File extension */ protected abstract String getFileExtension(); /** * Generates tuples to be output for testing * * @param num * Number of tuples to generate * @return Iterator of tuples */ protected abstract Iterator<T> generateTuples(int num); /** * Counts tuples in the output file * * @param f * Output file * @return Tuple count */ protected final long countTuples(File f) { StreamRDFCounting counter = StreamRDFLib.count(); RDFDataMgr.parse(counter, f.getAbsolutePath(), this.getRdfLanguage()); return counter.count(); } /** * Checks that tuples are as expected * * @param f * File * @param expected * Expected number of tuples */ protected void checkTuples(File f, long expected) { Assert.assertEquals(expected, this.countTuples(f)); } /** * Gets the RDF language of the produced output which is used to parse back * in the output to validate the correct amount of output was produced * * @return RDF language */ protected abstract Lang getRdfLanguage(); /** * Gets the output format to test * * @return Output format */ protected abstract OutputFormat<NullWritable, T> getOutputFormat(); /** * Adds an output path to the job configuration * * @param f * File * @param config * Configuration * @param job * Job * @throws IOException */ protected void addOutputPath(File f, Configuration config, Job job) throws IOException { FileSystem fs = FileSystem.getLocal(config); Path outputPath = fs.makeQualified(new Path(f.getAbsolutePath())); FileOutputFormat.setOutputPath(job, outputPath); } protected File findOutputFile(File dir, JobContext context) throws FileNotFoundException, IOException { Path outputPath = FileOutputFormat.getOutputPath(context); RemoteIterator<LocatedFileStatus> files = outputPath.getFileSystem(context.getConfiguration()) .listFiles(outputPath, true); while (files.hasNext()) { LocatedFileStatus status = files.next(); if (status.isFile() && !status.getPath().getName().startsWith("_")) { return new File(status.getPath().toUri()); } } return null; } /** * Tests output * * @param f * File to output to * @param num * Number of tuples to output * @throws IOException * @throws InterruptedException */ protected final void testOutput(File f, int num) throws IOException, InterruptedException { // Prepare configuration Configuration config = this.prepareConfiguration(); // Set up fake job OutputFormat<NullWritable, T> outputFormat = this.getOutputFormat(); Job job = Job.getInstance(config); job.setOutputFormatClass(outputFormat.getClass()); this.addOutputPath(f, job.getConfiguration(), job); JobContext context = new JobContextImpl(job.getConfiguration(), job.getJobID()); Assert.assertNotNull(FileOutputFormat.getOutputPath(context)); // Output the data TaskAttemptID id = new TaskAttemptID("outputTest", 1, TaskType.MAP, 1, 1); TaskAttemptContext taskContext = new TaskAttemptContextImpl(job.getConfiguration(), id); RecordWriter<NullWritable, T> writer = outputFormat.getRecordWriter(taskContext); Iterator<T> tuples = this.generateTuples(num); while (tuples.hasNext()) { writer.write(NullWritable.get(), tuples.next()); } writer.close(taskContext); // Check output File outputFile = this.findOutputFile(this.folder.getRoot(), context); Assert.assertNotNull(outputFile); this.checkTuples(outputFile, num); } /** * Basic output tests * * @throws IOException * @throws InterruptedException */ @Test public void output_01() throws IOException, InterruptedException { this.testOutput(this.folder.getRoot(), EMPTY_SIZE); } /** * Basic output tests * * @throws IOException * @throws InterruptedException */ @Test public void output_02() throws IOException, InterruptedException { this.testOutput(this.folder.getRoot(), SMALL_SIZE); } /** * Basic output tests * * @throws IOException * @throws InterruptedException */ @Test public void output_03() throws IOException, InterruptedException { this.testOutput(this.folder.getRoot(), LARGE_SIZE); } /** * Basic output tests * * @throws IOException * @throws InterruptedException */ @Test public void output_04() throws IOException, InterruptedException { this.testOutput(this.folder.getRoot(), VERY_LARGE_SIZE); } }