| /** |
| * 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.storm.starter; |
| |
| import java.io.Serializable; |
| import java.util.UUID; |
| import org.apache.storm.Config; |
| import org.apache.storm.topology.ConfigurableTopology; |
| import org.apache.storm.topology.TopologyBuilder; |
| import org.apache.storm.tuple.Values; |
| |
| public class LambdaTopology extends ConfigurableTopology { |
| public static void main(String[] args) { |
| ConfigurableTopology.start(new LambdaTopology(), args); |
| } |
| |
| @Override |
| protected int run(String[] args) throws Exception { |
| TopologyBuilder builder = new TopologyBuilder(); |
| |
| // example. spout1: generate random strings |
| // bolt1: get the first part of a string |
| // bolt2: output the tuple |
| |
| // NOTE: Variable used in lambda expression should be final or effectively final |
| // (or it will cause compilation error), |
| // and variable type should implement the Serializable interface if it isn't primitive type |
| // (or it will cause not serializable exception). |
| Prefix prefix = new Prefix("Hello lambda:"); |
| String suffix = ":so cool!"; |
| int tag = 999; |
| |
| builder.setSpout("spout1", () -> UUID.randomUUID().toString()); |
| builder.setBolt("bolt1", (tuple, collector) -> { |
| String[] parts = tuple.getStringByField("lambda").split("\\-"); |
| collector.emit(new Values(prefix + parts[0] + suffix, tag)); |
| }, "strValue", "intValue").shuffleGrouping("spout1"); |
| builder.setBolt("bolt2", tuple -> System.out.println(tuple)).shuffleGrouping("bolt1"); |
| |
| Config conf = new Config(); |
| conf.setDebug(true); |
| conf.setNumWorkers(2); |
| |
| return submit("lambda-demo", conf, builder); |
| } |
| } |