storm-compatibility-examples/src/java/org/apache/storm/examples/spout/TestWordSpout.java

/**
 * 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.examples.spout;

import java.time.Duration;
import java.util.Map;
import java.util.Random;

import org.apache.storm.spout.SpoutOutputCollector;
import org.apache.storm.task.TopologyContext;
import org.apache.storm.topology.OutputFieldsDeclarer;
import org.apache.storm.topology.base.BaseRichSpout;
import org.apache.storm.tuple.Fields;
import org.apache.storm.tuple.Values;
import org.apache.storm.utils.Utils;

public class TestWordSpout extends BaseRichSpout {

  private static final long serialVersionUID = -3217886193225455451L;
  private SpoutOutputCollector collector;
  private String[] words;
  private Random rand;
  private final Duration throttleDuration;

  public TestWordSpout() {
    this(Duration.ZERO);
  }

  public TestWordSpout(Duration throttleDuration) {
    this.throttleDuration = throttleDuration;
  }

  @SuppressWarnings("rawtypes")
  public void open(
      Map conf,
      TopologyContext context,
      SpoutOutputCollector acollector) {
    collector = acollector;
    words = new String[]{"nathan", "mike", "jackson", "golda", "bertels"};
    rand = new Random();
  }

  public void close() {
  }

  public void nextTuple() {
    final String word = words[rand.nextInt(words.length)];
    collector.emit(new Values(word));
    if (!throttleDuration.isZero()) {
      Utils.sleep(throttleDuration.toMillis()); // sleep to throttle back CPU usage
    }
  }

  public void ack(Object msgId) {
  }

  public void fail(Object msgId) {
  }

  public void declareOutputFields(OutputFieldsDeclarer declarer) {
    declarer.declare(new Fields("word"));
  }
}