org.apache.beam.learning.katas.triggers.earlytriggers.GenerateEvent.java Source code

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Here is the source code for org.apache.beam.learning.katas.triggers.earlytriggers.GenerateEvent.java

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/*
 * 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.earlytriggers;

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"));
    }

}