| /* |
| * 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.ignite.examples.computegrid; |
| |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Map; |
| import org.apache.ignite.Ignite; |
| import org.apache.ignite.IgniteException; |
| import org.apache.ignite.Ignition; |
| import org.apache.ignite.cluster.ClusterNode; |
| import org.apache.ignite.compute.ComputeJob; |
| import org.apache.ignite.compute.ComputeJobAdapter; |
| import org.apache.ignite.compute.ComputeJobResult; |
| import org.apache.ignite.compute.ComputeTaskAdapter; |
| import org.apache.ignite.examples.ExampleNodeStartup; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| /** |
| * Demonstrates a simple use of Ignite with |
| * {@link ComputeTaskAdapter}. |
| * <p> |
| * Phrase passed as task argument is split into words on map stage and distributed among cluster nodes. |
| * Each node computes word length and returns result to master node where total phrase length is |
| * calculated on reduce stage. |
| * <p> |
| * Remote nodes should always be started with special configuration file which |
| * enables P2P class loading: {@code 'ignite.{sh|bat} examples/config/example-ignite.xml'}. |
| * <p> |
| * Alternatively you can run {@link ExampleNodeStartup} in another JVM which will start node |
| * with {@code examples/config/example-ignite.xml} configuration. |
| */ |
| public class ComputeTaskMapExample { |
| /** |
| * Executes example. |
| * |
| * @param args Command line arguments, none required. |
| * @throws IgniteException If example execution failed. |
| */ |
| public static void main(String[] args) throws IgniteException { |
| try (Ignite ignite = Ignition.start("examples/config/example-ignite.xml")) { |
| System.out.println(); |
| System.out.println("Compute task map example started."); |
| |
| // Execute task on the cluster and wait for its completion. |
| int cnt = ignite.compute().execute(MapExampleCharacterCountTask.class, "Hello Ignite Enabled World!"); |
| |
| System.out.println(); |
| System.out.println(">>> Total number of characters in the phrase is '" + cnt + "'."); |
| System.out.println(">>> Check all nodes for output (this node is also part of the cluster)."); |
| } |
| } |
| |
| /** |
| * Task to count non-white-space characters in a phrase. |
| */ |
| private static class MapExampleCharacterCountTask extends ComputeTaskAdapter<String, Integer> { |
| /** |
| * Splits the received string to words, creates a child job for each word, and sends |
| * these jobs to other nodes for processing. Each such job simply prints out the received word. |
| * |
| * @param nodes Nodes available for this task execution. |
| * @param arg String to split into words for processing. |
| * @return Map of jobs to nodes. |
| */ |
| @NotNull @Override public Map<? extends ComputeJob, ClusterNode> map(List<ClusterNode> nodes, String arg) { |
| Map<ComputeJob, ClusterNode> map = new HashMap<>(); |
| |
| Iterator<ClusterNode> it = nodes.iterator(); |
| |
| for (final String word : arg.split(" ")) { |
| // If we used all nodes, restart the iterator. |
| if (!it.hasNext()) |
| it = nodes.iterator(); |
| |
| ClusterNode node = it.next(); |
| |
| map.put(new ComputeJobAdapter() { |
| @Nullable @Override public Object execute() { |
| System.out.println(); |
| System.out.println(">>> Printing '" + word + "' on this node from ignite job."); |
| |
| // Return number of letters in the word. |
| return word.length(); |
| } |
| }, node); |
| } |
| |
| return map; |
| } |
| |
| /** {@inheritDoc} */ |
| @Nullable @Override public Integer reduce(List<ComputeJobResult> results) { |
| int sum = 0; |
| |
| for (ComputeJobResult res : results) |
| sum += res.<Integer>getData(); |
| |
| return sum; |
| } |
| } |
| } |