content: /*
   * 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.beam.learning.katas.triggers.eventtimetriggers;
  
  import static org.apache.beam.sdk.values.TypeDescriptors.strings;
  
  import org.apache.beam.sdk.io.GenerateSequence;
  import org.apache.beam.sdk.transforms.MapElements;
  import org.apache.beam.sdk.transforms.PTransform;
  import org.apache.beam.sdk.values.PBegin;
  import org.apache.beam.sdk.values.PCollection;
  import org.joda.time.Duration;
  
  public class GenerateEvent extends PTransform<PBegin, PCollection<String>> {
  
    static GenerateEvent everySecond() {
      return new GenerateEvent();
    }
  
    public PCollection<String> expand(PBegin input) {
      return input
          .apply(GenerateSequence.from(1).withRate(1, Duration.standardSeconds(1)))
          .apply(MapElements.into(strings()).via(num -> "event"));
    }
  
  }
  