com.dataartisans.queryablestatedemo.BumpEventGeneratorSource.java Source code

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Here is the source code for com.dataartisans.queryablestatedemo.BumpEventGeneratorSource.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 com.dataartisans.queryablestatedemo;

import java.util.Random;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.commons.lang3.RandomStringUtils;
import org.apache.flink.streaming.api.functions.source.RichSourceFunction;

/**
 * A (non-parallel) {@link BumpEvent} generator source.
 */
class BumpEventGeneratorSource extends RichSourceFunction<BumpEvent> {

    private static final long serialVersionUID = 244478060020939187L;

    /**
     * Number of alpha numeric characters of the items.
     */
    private static final int ITEM_ID_NUM_CHARS = 3;

    /**
     * Flag indicating whether we should print the throughput. If true, the {@link ThroughputLogger}
     * thread is started.
     */
    private final boolean printThroughput;

    /**
     * Flag indicating whether we are still running.
     */
    private volatile boolean running = true;

    BumpEventGeneratorSource(boolean printThroughput) {
        this.printThroughput = printThroughput;
    }

    @Override
    public void run(SourceContext<BumpEvent> sourceContext) throws Exception {
        final Random rand = new Random();
        final AtomicLong count = new AtomicLong();

        Thread throughputLogger = null;
        if (printThroughput) {
            throughputLogger = new Thread(new ThroughputLogger(count), "ThroughputLogger");
            throughputLogger.start();
        }

        try {
            while (running) {
                // Generate random events
                final int userId = rand.nextInt(Integer.MAX_VALUE);

                final String itemCase = RandomStringUtils.randomAlphanumeric(ITEM_ID_NUM_CHARS).toLowerCase();

                synchronized (sourceContext.getCheckpointLock()) {
                    sourceContext.collect(new BumpEvent(userId, itemCase));
                }

                // Increment count for throughput logger
                count.incrementAndGet();

                Thread.yield();
            }
        } finally {
            if (throughputLogger != null) {
                throughputLogger.interrupt();
                throughputLogger.join();
            }
        }
    }

    @Override
    public void cancel() {
        running = false;
    }

    // --------------------------------------------------------------------------

    private static class ThroughputLogger implements Runnable {

        private final AtomicLong count;

        ThroughputLogger(AtomicLong count) {
            this.count = count;
        }

        @Override
        public void run() {
            long lastCount = 0L;
            long lastTimestamp = System.currentTimeMillis();

            while (!Thread.interrupted()) {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    return;
                }

                final long ts = System.currentTimeMillis();

                final long currCount = count.get();

                final double factor = (ts - lastTimestamp) / 1000.0;
                final int perSec = (int) ((currCount - lastCount) / factor);

                lastTimestamp = ts;
                lastCount = currCount;

                System.out.println(String.format("Generating %d elements per second", perSec));
            }
        }
    }

}