| /* |
| * 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.flink.training.exercises.common.sources; |
| |
| import org.apache.flink.streaming.api.functions.source.SourceFunction; |
| import org.apache.flink.training.exercises.common.datatypes.TaxiRide; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.PriorityQueue; |
| import java.util.Random; |
| |
| /** |
| * This SourceFunction generates a data stream of TaxiRide records. |
| * |
| * <p>The stream is produced out-of-order. |
| */ |
| public class TaxiRideGenerator implements SourceFunction<TaxiRide> { |
| |
| public static final int SLEEP_MILLIS_PER_EVENT = 10; |
| private static final int BATCH_SIZE = 5; |
| private volatile boolean running = true; |
| |
| @Override |
| public void run(SourceContext<TaxiRide> ctx) throws Exception { |
| |
| PriorityQueue<TaxiRide> endEventQ = new PriorityQueue<>(100); |
| long id = 0; |
| long maxStartTime = 0; |
| |
| while (running) { |
| |
| // generate a batch of START events |
| List<TaxiRide> startEvents = new ArrayList<TaxiRide>(BATCH_SIZE); |
| for (int i = 1; i <= BATCH_SIZE; i++) { |
| TaxiRide ride = new TaxiRide(id + i, true); |
| startEvents.add(ride); |
| // the start times may be in order, but let's not assume that |
| maxStartTime = Math.max(maxStartTime, ride.startTime.toEpochMilli()); |
| } |
| |
| // enqueue the corresponding END events |
| for (int i = 1; i <= BATCH_SIZE; i++) { |
| endEventQ.add(new TaxiRide(id + i, false)); |
| } |
| |
| // release the END events coming before the end of this new batch |
| // (this allows a few END events to precede their matching START event) |
| while (endEventQ.peek().getEventTime() <= maxStartTime) { |
| TaxiRide ride = endEventQ.poll(); |
| ctx.collect(ride); |
| } |
| |
| // then emit the new START events (out-of-order) |
| java.util.Collections.shuffle(startEvents, new Random(id)); |
| startEvents |
| .iterator() |
| .forEachRemaining(r -> ctx.collectWithTimestamp(r, r.getEventTime())); |
| |
| // prepare for the next batch |
| id += BATCH_SIZE; |
| |
| // don't go too fast |
| Thread.sleep(BATCH_SIZE * SLEEP_MILLIS_PER_EVENT); |
| } |
| } |
| |
| @Override |
| public void cancel() { |
| running = false; |
| } |
| } |