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.
   */
  
  // beam-playground:
  //   name: group
  //   description: Group example.
  //   multifile: false
  //   context_line: 130
  //   categories:
  //     - Quickstart
  //   complexity: ADVANCED
  //   tags:
  //     - hellobeam
  
  import org.apache.beam.sdk.Pipeline;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.coders.StringUtf8Coder;
  import org.apache.beam.sdk.io.TextIO;
  import org.apache.beam.sdk.options.PipelineOptions;
  import org.apache.beam.sdk.options.PipelineOptionsFactory;
  import org.apache.beam.sdk.schemas.JavaFieldSchema;
  import org.apache.beam.sdk.schemas.Schema;
  import org.apache.beam.sdk.schemas.annotations.DefaultSchema;
  import org.apache.beam.sdk.schemas.annotations.SchemaCreate;
  import org.apache.beam.sdk.schemas.transforms.Group;
  import org.apache.beam.sdk.transforms.*;
  import org.apache.beam.sdk.util.StreamUtils;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.Row;
  import org.apache.beam.sdk.values.TypeDescriptor;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.Collections;
  import java.util.List;
  
  public class Task {
      private static final Logger LOG = LoggerFactory.getLogger(Task.class);
  
      @DefaultSchema(JavaFieldSchema.class)
      public static class Game {
          public String userId;
          public Integer score;
          public String gameId;
          public String date;
  
          @SchemaCreate
          public Game(String userId, Integer score, String gameId, String date) {
              this.userId = userId;
              this.score = score;
              this.gameId = gameId;
              this.date = date;
          }
  
          @Override
          public String toString() {
              return "Game{" +
                      "userId='" + userId + '\'' +
                      ", score='" + score + '\'' +
                      ", gameId='" + gameId + '\'' +
                      ", date='" + date + '\'' +
                      '}';
          }
      }
  
      // User schema
      @DefaultSchema(JavaFieldSchema.class)
      public static class User {
  
          public String userId;
          public String userName;
          public Game game;
  
          @SchemaCreate
          public User(String userId, String userName, Game game) {
              this.userId = userId;
              this.userName = userName;
              this.game = game;
          }
  
          @Override
          public String toString() {
              return "User{" +
                      "userId='" + userId + '\'' +
                      ", userName='" + userName + '\'' +
                      ", game=" + game +
                      '}';
          }
      }
  
      public static void main(String[] args) {
          PipelineOptions options = PipelineOptionsFactory.fromArgs(args).create();
          Pipeline pipeline = Pipeline.create(options);
  
          PCollection<User> input = getProgressPCollection(pipeline);
  
          Schema type = Schema.builder()
                  .addStringField("userId")
                  .addStringField("userName")
                  .addInt32Field("score")
                  .addStringField("gameId")
                  .addStringField("date")
                  .build();
  
          PCollection<String> pCollection = input
                  .apply(MapElements.into(TypeDescriptor.of(Object.class)).via(it -> it))
                  .setSchema(type,
                          TypeDescriptor.of(Object.class), row ->
                          {
                              User user = (User) row;
                              return Row.withSchema(type)
                                      .addValues(user.userId, user.userName, user.game.score, user.game.gameId, user.game.date)
                                      .build();
                          },
                          row -> new User(row.getString(0), row.getString(1),
                                  new Game(row.getString(0), row.getInt32(2), row.getString(3), row.getString(4)))
                  )
                  .apply(Group.byFieldNames("userId").aggregateField("score", Sum.ofIntegers(), "total"))
                  .apply(MapElements.into(TypeDescriptor.of(String.class)).via(row -> row.getRow(0).getValue(0) + " : " + row.getRow(1).getValue(0)));
  
          pCollection
                  .setCoder(StringUtf8Coder.of())
                  .apply("User flatten row", ParDo.of(new LogOutput<>("Flattened")));
  
          pipeline.run();
      }
  
      public static PCollection<User> getProgressPCollection(Pipeline pipeline) {
          PCollection<String> rides = pipeline.apply(TextIO.read().from("gs://apache-beam-samples/game/small/gaming_data.csv"));
          final PTransform<PCollection<String>, PCollection<Iterable<String>>> sample = Sample.fixedSizeGlobally(100);
          return rides.apply(sample).apply(Flatten.iterables()).apply(ParDo.of(new ExtractUserProgressFn())).setCoder(CustomCoder.of());
      }
  
      static class ExtractUserProgressFn extends DoFn<String, User> {
          @ProcessElement
          public void processElement(ProcessContext c) {
              String[] items = c.element().split(",");
              c.output(new User(items[0], items[1], new Game(items[0], Integer.valueOf(items[2]), items[3], items[4])
              ));
          }
      }
  
      static class CustomCoder extends Coder<User> {
          private static final CustomCoder INSTANCE = new CustomCoder();
  
          public static CustomCoder of() {
              return INSTANCE;
          }
  
          @Override
          public void encode(User user, OutputStream outStream) throws IOException {
              String line = user.userId + "," + user.userName + ";" + user.game.score + "," + user.game.gameId + "," + user.game.date;
              outStream.write(line.getBytes());
          }
  
          @Override
          public User decode(InputStream inStream) throws IOException {
              final String serializedDTOs = new String(StreamUtils.getBytesWithoutClosing(inStream));
              String[] params = serializedDTOs.split(";");
              String[] user = params[0].split(",");
              String[] game = params[1].split(",");
              return new User(user[0], user[1], new Game(user[0], Integer.valueOf(game[0]), game[1], game[2]));
          }
  
          @Override
          public List<? extends Coder<?>> getCoderArguments() {
              return Collections.emptyList();
          }
  
          @Override
          public void verifyDeterministic() {
          }
      }
  
      static class LogOutput<T> extends DoFn<T, T> {
  
          private final String prefix;
  
          LogOutput() {
              this.prefix = "Processing element";
          }
  
          LogOutput(String prefix) {
              this.prefix = prefix;
          }
  
          @ProcessElement
          public void processElement(ProcessContext c) throws Exception {
              LOG.info(prefix + ": {}", c.element());
          }
      }
  }
  