content: /*
   * 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.model.Auction;
  import org.apache.beam.sdk.nexmark.model.Bid;
  import org.apache.beam.sdk.nexmark.model.Event;
  import org.apache.beam.sdk.nexmark.model.Person;
  import org.apache.beam.sdk.transforms.DoFn;
  import org.apache.beam.sdk.transforms.Filter;
  import org.apache.beam.sdk.transforms.PTransform;
  import org.apache.beam.sdk.transforms.ParDo;
  import org.apache.beam.sdk.transforms.SerializableFunction;
  import org.apache.beam.sdk.values.KV;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.TupleTag;
  
  /** Utilities for working with NEXmark data stream. */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class NexmarkQueryUtil {
    // Do not instantiate
    private NexmarkQueryUtil() {}
  
    public static final TupleTag<Auction> AUCTION_TAG = new TupleTag<>("auctions");
    public static final TupleTag<Bid> BID_TAG = new TupleTag<>("bids");
    public static final TupleTag<Person> PERSON_TAG = new TupleTag<>("person");
  
    /** Predicate to detect a new person event. */
    public static final SerializableFunction<Event, Boolean> IS_NEW_PERSON =
        event -> event.newPerson != null;
  
    /** DoFn to convert a new person event to a person. */
    public static final DoFn<Event, Person> AS_PERSON =
        new DoFn<Event, Person>() {
          @ProcessElement
          public void processElement(ProcessContext c) {
            c.output(c.element().newPerson);
          }
        };
  
    /** Predicate to detect a new auction event. */
    public static final SerializableFunction<Event, Boolean> IS_NEW_AUCTION =
        event -> event.newAuction != null;
  
    /** DoFn to convert a new auction event to an auction. */
    public static final DoFn<Event, Auction> AS_AUCTION =
        new DoFn<Event, Auction>() {
          @ProcessElement
          public void processElement(ProcessContext c) {
            c.output(c.element().newAuction);
          }
        };
  
    /** Predicate to detect a new bid event. */
    public static final SerializableFunction<Event, Boolean> IS_BID = event -> event.bid != null;
  
    /** DoFn to convert a bid event to a bid. */
    public static final DoFn<Event, Bid> AS_BID =
        new DoFn<Event, Bid>() {
          @ProcessElement
          public void processElement(ProcessContext c) {
            c.output(c.element().bid);
          }
        };
  
    /** Transform to key each person by their id. */
    public static final ParDo.SingleOutput<Person, KV<Long, Person>> PERSON_BY_ID =
        ParDo.of(
            new DoFn<Person, KV<Long, Person>>() {
              @ProcessElement
              public void processElement(ProcessContext c) {
                c.output(KV.of(c.element().id, c.element()));
              }
            });
  
    /** Transform to key each auction by its id. */
    public static final ParDo.SingleOutput<Auction, KV<Long, Auction>> AUCTION_BY_ID =
        ParDo.of(
            new DoFn<Auction, KV<Long, Auction>>() {
              @ProcessElement
              public void processElement(ProcessContext c) {
                c.output(KV.of(c.element().id, c.element()));
              }
            });
  
    /** Transform to key each auction by its seller id. */
    public static final ParDo.SingleOutput<Auction, KV<Long, Auction>> AUCTION_BY_SELLER =
        ParDo.of(
            new DoFn<Auction, KV<Long, Auction>>() {
              @ProcessElement
              public void processElement(ProcessContext c) {
                c.output(KV.of(c.element().seller, c.element()));
              }
            });
  
    /** Transform to key each bid by it's auction id. */
    public static final ParDo.SingleOutput<Bid, KV<Long, Bid>> BID_BY_AUCTION =
        ParDo.of(
            new DoFn<Bid, KV<Long, Bid>>() {
              @ProcessElement
              public void processElement(ProcessContext c) {
                c.output(KV.of(c.element().auction, c.element()));
              }
            });
  
    /** Transform to project the auction id from each bid. */
    public static final ParDo.SingleOutput<Bid, Long> BID_TO_AUCTION =
        ParDo.of(
            new DoFn<Bid, Long>() {
              @ProcessElement
              public void processElement(ProcessContext c) {
                c.output(c.element().auction);
              }
            });
  
    /** Transform to project the price from each bid. */
    public static final ParDo.SingleOutput<Bid, Long> BID_TO_PRICE =
        ParDo.of(
            new DoFn<Bid, Long>() {
              @ProcessElement
              public void processElement(ProcessContext c) {
                c.output(c.element().price);
              }
            });
  
    /** Transform to emit each event with the timestamp embedded within it. */
    public static final ParDo.SingleOutput<Event, Event> EVENT_TIMESTAMP_FROM_DATA =
        ParDo.of(
            new DoFn<Event, Event>() {
              @ProcessElement
              public void processElement(ProcessContext c) {
                Event e = c.element();
                if (e.bid != null) {
                  c.outputWithTimestamp(e, e.bid.dateTime);
                } else if (e.newPerson != null) {
                  c.outputWithTimestamp(e, e.newPerson.dateTime);
                } else if (e.newAuction != null) {
                  c.outputWithTimestamp(e, e.newAuction.dateTime);
                }
              }
            });
  
    /** Transform to filter for just the new auction events. */
    public static final PTransform<PCollection<Event>, PCollection<Auction>> JUST_NEW_AUCTIONS =
        new PTransform<PCollection<Event>, PCollection<Auction>>("justNewAuctions") {
          @Override
          public PCollection<Auction> expand(PCollection<Event> input) {
            return input
                .apply("IsNewAuction", Filter.by(IS_NEW_AUCTION))
                .apply("AsAuction", ParDo.of(AS_AUCTION));
          }
        };
  
    /** Transform to filter for just the new person events. */
    public static final PTransform<PCollection<Event>, PCollection<Person>> JUST_NEW_PERSONS =
        new PTransform<PCollection<Event>, PCollection<Person>>("justNewPersons") {
          @Override
          public PCollection<Person> expand(PCollection<Event> input) {
            return input
                .apply("IsNewPerson", Filter.by(IS_NEW_PERSON))
                .apply("AsPerson", ParDo.of(AS_PERSON));
          }
        };
  
    /** Transform to filter for just the bid events. */
    public static final PTransform<PCollection<Event>, PCollection<Bid>> JUST_BIDS =
        new PTransform<PCollection<Event>, PCollection<Bid>>("justBids") {
          @Override
          public PCollection<Bid> expand(PCollection<Event> input) {
            return input.apply("IsBid", Filter.by(IS_BID)).apply("AsBid", ParDo.of(AS_BID));
          }
        };
  }
  