org.apache.beam.sdk.nexmark.queries.Query11.java Source code

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Here is the source code for org.apache.beam.sdk.nexmark.queries.Query11.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.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.AfterPane;
import org.apache.beam.sdk.transforms.windowing.Repeatedly;
import org.apache.beam.sdk.transforms.windowing.Sessions;
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 "11", 'User sessions' (Not in original suite.)
 *
 * <p>Group bids by the same user into sessions with {@code windowSizeSec} max gap. However limit
 * the session to at most {@code maxLogEvents}. Emit the number of bids per session.
 */
public class Query11 extends NexmarkQueryTransform<BidsPerSession> {
    private final NexmarkConfiguration configuration;

    public Query11(NexmarkConfiguration configuration) {
        super("Query11");
        this.configuration = configuration;
    }

    @Override
    public PCollection<BidsPerSession> expand(PCollection<Event> events) {
        PCollection<Long> bidders = events.apply(NexmarkQueryUtil.JUST_BIDS).apply(name + ".Rekey",
                ParDo.of(new DoFn<Bid, Long>() {

                    @ProcessElement
                    public void processElement(ProcessContext c) {
                        Bid bid = c.element();
                        c.output(bid.bidder);
                    }
                }));

        PCollection<Long> biddersWindowed = bidders.apply(
                Window.<Long>into(Sessions.withGapDuration(Duration.standardSeconds(configuration.windowSizeSec)))
                        .triggering(Repeatedly.forever(AfterPane.elementCountAtLeast(configuration.maxLogEvents)))
                        .discardingFiredPanes()
                        .withAllowedLateness(Duration.standardSeconds(configuration.occasionalDelaySec / 2)));
        return biddersWindowed.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()));
                    }
                }));
    }
}