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.examples.complete.game.utils;
  
  import com.google.api.services.bigquery.model.TableFieldSchema;
  import com.google.api.services.bigquery.model.TableReference;
  import com.google.api.services.bigquery.model.TableRow;
  import com.google.api.services.bigquery.model.TableSchema;
  import java.io.Serializable;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO.Write.CreateDisposition;
  import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO.Write.WriteDisposition;
  import org.apache.beam.sdk.io.gcp.bigquery.InsertRetryPolicy;
  import org.apache.beam.sdk.transforms.DoFn;
  import org.apache.beam.sdk.transforms.PTransform;
  import org.apache.beam.sdk.transforms.ParDo;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.PDone;
  
  /**
   * Generate, format, and write BigQuery table row information. Use provided information about the
   * field names and types, as well as lambda functions that describe how to generate their values.
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class WriteToBigQuery<InputT> extends PTransform<PCollection<InputT>, PDone> {
  
    protected String projectId;
    protected String datasetId;
    protected String tableName;
    protected Map<String, FieldInfo<InputT>> fieldInfo;
  
    public WriteToBigQuery() {}
  
    public WriteToBigQuery(
        String projectId,
        String datasetId,
        String tableName,
        Map<String, FieldInfo<InputT>> fieldInfo) {
      this.projectId = projectId;
      this.datasetId = datasetId;
      this.tableName = tableName;
      this.fieldInfo = fieldInfo;
    }
  
    /**
     * A {@link Serializable} function from a {@link DoFn.ProcessContext} and {@link BoundedWindow} to
     * the value for that field.
     */
    public interface FieldFn<InputT> extends Serializable {
      Object apply(DoFn<InputT, TableRow>.ProcessContext context, BoundedWindow window);
    }
  
    /** Define a class to hold information about output table field definitions. */
    public static class FieldInfo<InputT> implements Serializable {
      // The BigQuery 'type' of the field
      private String fieldType;
      // A lambda function to generate the field value
      private FieldFn<InputT> fieldFn;
  
      public FieldInfo(String fieldType, FieldFn<InputT> fieldFn) {
        this.fieldType = fieldType;
        this.fieldFn = fieldFn;
      }
  
      String getFieldType() {
        return this.fieldType;
      }
  
      FieldFn<InputT> getFieldFn() {
        return this.fieldFn;
      }
    }
  
    /** Convert each key/score pair into a BigQuery TableRow as specified by fieldFn. */
    protected class BuildRowFn extends DoFn<InputT, TableRow> {
  
      @ProcessElement
      public void processElement(ProcessContext c, BoundedWindow window) {
  
        TableRow row = new TableRow();
        for (Map.Entry<String, FieldInfo<InputT>> entry : fieldInfo.entrySet()) {
          String key = entry.getKey();
          FieldInfo<InputT> fcnInfo = entry.getValue();
          FieldFn<InputT> fcn = fcnInfo.getFieldFn();
          row.set(key, fcn.apply(c, window));
        }
        c.output(row);
      }
    }
  
    /** Build the output table schema. */
    protected TableSchema getSchema() {
      List<TableFieldSchema> fields = new ArrayList<>();
      for (Map.Entry<String, FieldInfo<InputT>> entry : fieldInfo.entrySet()) {
        String key = entry.getKey();
        FieldInfo<InputT> fcnInfo = entry.getValue();
        String bqType = fcnInfo.getFieldType();
        fields.add(new TableFieldSchema().setName(key).setType(bqType));
      }
      return new TableSchema().setFields(fields);
    }
  
    @Override
    public PDone expand(PCollection<InputT> teamAndScore) {
      teamAndScore
          .apply("ConvertToRow", ParDo.of(new BuildRowFn()))
          .apply(
              BigQueryIO.writeTableRows()
                  .to(getTable(projectId, datasetId, tableName))
                  .withSchema(getSchema())
                  .withCreateDisposition(CreateDisposition.CREATE_IF_NEEDED)
                  .withWriteDisposition(WriteDisposition.WRITE_APPEND)
                  .withFailedInsertRetryPolicy(InsertRetryPolicy.retryTransientErrors()));
      return PDone.in(teamAndScore.getPipeline());
    }
  
    /** Utility to construct an output table reference. */
    static TableReference getTable(String projectId, String datasetId, String tableName) {
      TableReference table = new TableReference();
      table.setDatasetId(datasetId);
      table.setProjectId(projectId);
      table.setTableId(tableName);
      return table;
    }
  }
  