Java tutorial
/* * 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.sdk.nexmark.queries; import org.apache.beam.sdk.nexmark.NexmarkConfiguration; import org.apache.beam.sdk.nexmark.model.Bid; import org.apache.beam.sdk.nexmark.model.BidsPerSession; import org.apache.beam.sdk.nexmark.model.Event; import org.apache.beam.sdk.transforms.Count; import org.apache.beam.sdk.transforms.DoFn; import org.apache.beam.sdk.transforms.ParDo; import org.apache.beam.sdk.transforms.windowing.AfterProcessingTime; import org.apache.beam.sdk.transforms.windowing.GlobalWindows; import org.apache.beam.sdk.transforms.windowing.Repeatedly; import org.apache.beam.sdk.transforms.windowing.Window; import org.apache.beam.sdk.values.KV; import org.apache.beam.sdk.values.PCollection; import org.joda.time.Duration; /** * Query "12", 'Processing time windows' (Not in original suite.) * * <p>Group bids by the same user into processing time windows of windowSize. Emit the count of bids * per window. */ public class Query12 extends NexmarkQueryTransform<BidsPerSession> { private final NexmarkConfiguration configuration; public Query12(NexmarkConfiguration configuration) { super("Query12"); this.configuration = configuration; } @Override public PCollection<BidsPerSession> expand(PCollection<Event> events) { return events.apply(NexmarkQueryUtil.JUST_BIDS).apply(ParDo.of(new DoFn<Bid, Long>() { @ProcessElement public void processElement(ProcessContext c) { c.output(c.element().bidder); } })).apply(Window.<Long>into(new GlobalWindows()) .triggering(Repeatedly.forever(AfterProcessingTime.pastFirstElementInPane() .plusDelayOf(Duration.standardSeconds(configuration.windowSizeSec)))) .discardingFiredPanes().withAllowedLateness(Duration.ZERO)).apply(Count.perElement()) .apply(name + ".ToResult", ParDo.of(new DoFn<KV<Long, Long>, BidsPerSession>() { @ProcessElement public void processElement(ProcessContext c) { c.output(new BidsPerSession(c.element().getKey(), c.element().getValue())); } })); } }