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 com.tdunning.plume.local.lazy; import static com.tdunning.plume.Plume.collectionOf; import static com.tdunning.plume.Plume.strings; import static com.tdunning.plume.Plume.tableOf; import java.io.IOException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.Text; import org.junit.Test; import com.google.common.io.Resources; import com.tdunning.plume.DoFn; import com.tdunning.plume.EmitFn; import com.tdunning.plume.PCollection; import com.tdunning.plume.Pair; /** * */ public class MapRedSingleFlattenChannelTest { /** * In this example we open a file and apply two functions to it. One of them performs a group by key and the other one * just adds as output the result of the second function (bypass channel). */ public static class MapRedSingleFlattenChannelTestWorkflow extends PlumeWorkflow { public MapRedSingleFlattenChannelTestWorkflow() { } @SuppressWarnings("unchecked") @Override public void build() { init(); LazyPlume plume = new LazyPlume(); PCollection input; PCollection input2; try { // Read input input = plume.readFile("/tmp/input-wordcount.txt", collectionOf(strings())); input2 = plume.readFile("/tmp/input-moretext.txt", collectionOf(strings())); // Add it as workflow's input addInput(input); } catch (IOException e) { throw new RuntimeException(); } PCollection transform = input.map(new DoFn() { @Override public void process(Object v, EmitFn emitter) { Text t = (Text) v; emitter.emit(new Text(t.toString() + "-bar")); } }, collectionOf(strings())); addOutput(plume.flatten(input2, transform)); // flatten with another file PCollection groupedTransform = input.map(new DoFn() { @Override public void process(Object v, EmitFn emitter) { Text t = (Text) v; emitter.emit(Pair.create(t, new Text("foo"))); } }, tableOf(strings(), strings())).groupByKey(); addOutput(groupedTransform); } } @Test public void test() throws Exception { String outputPath = "/tmp/output-plume-singleflattenchanneltest"; String inputPath = "/tmp/input-wordcount.txt"; String inputPath2 = "/tmp/input-moretext.txt"; // Prepare input for test FileSystem system = FileSystem.getLocal(new Configuration()); system.copyFromLocalFile(new Path(Resources.getResource("simple-text.txt").getPath()), new Path(inputPath)); system.copyFromLocalFile(new Path(Resources.getResource("simple-text.txt").getPath()), new Path(inputPath2)); // Prepare output for test system.delete(new Path(outputPath), true); // Prepare workflow MapRedSingleFlattenChannelTestWorkflow workFlow = new MapRedSingleFlattenChannelTestWorkflow(); // Execute it MapRedExecutor executor = new MapRedExecutor(); executor.execute(workFlow, outputPath); /** * TODO add test validation */ } }