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.extensions.sql.meta.provider.datagen;
  
  import com.fasterxml.jackson.databind.node.ObjectNode;
  import java.util.List;
  import org.apache.beam.sdk.extensions.sql.impl.BeamTableStatistics;
  import org.apache.beam.sdk.extensions.sql.meta.BeamSqlTableFilter;
  import org.apache.beam.sdk.extensions.sql.meta.SchemaBaseBeamTable;
  import org.apache.beam.sdk.options.PipelineOptions;
  import org.apache.beam.sdk.schemas.Schema;
  import org.apache.beam.sdk.values.PBegin;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.PCollection.IsBounded;
  import org.apache.beam.sdk.values.POutput;
  import org.apache.beam.sdk.values.Row;
  
  /**
   * Represents a 'datagen' table within a Beam SQL pipeline. This class extends {@link
   * SchemaBaseBeamTable} to correctly implement the full {@link
   * org.apache.beam.sdk.extensions.sql.meta.BeamSqlTable} interface.
   */
  public class DataGeneratorTable extends SchemaBaseBeamTable {
    private final ObjectNode properties;
  
    public DataGeneratorTable(Schema schema, ObjectNode properties) {
      super(schema);
      this.properties = properties;
    }
  
    @Override
    public IsBounded isBounded() {
      // The table is bounded if 'number-of-rows' is specified, otherwise it is unbounded.
      return properties.has("number-of-rows") ? IsBounded.BOUNDED : IsBounded.UNBOUNDED;
    }
  
    @Override
    public PCollection<Row> buildIOReader(PBegin begin) {
      return begin.apply(
          "ReadFromDataGenerator", new DataGeneratorPTransform(getSchema(), properties));
    }
  
    @Override
    public PCollection<Row> buildIOReader(
        PBegin begin, BeamSqlTableFilter filters, List<String> fieldNames) {
      // DataGenerator does not support filter or project push-down.
      // This is a common pattern for IOs that do not support these optimizations.
      return buildIOReader(begin);
    }
  
    @Override
    public POutput buildIOWriter(PCollection<Row> input) {
      throw new UnsupportedOperationException("The 'datagen' table type is read-only.");
    }
  
    @Override
    public BeamTableStatistics getTableStatistics(PipelineOptions options) {
      // Safely provide statistics to the query planner.
      // Check for the bounded property first.
      if (properties.has("number-of-rows")) {
        double rowCount = properties.get("number-of-rows").asDouble();
        return BeamTableStatistics.createBoundedTableStatistics(rowCount);
      }
      // Then check for the unbounded property.
      else if (properties.has("rows-per-second")) {
        double rate = properties.get("rows-per-second").asDouble();
        return BeamTableStatistics.createUnboundedTableStatistics(rate);
      }
  
      // If neither property is present, the table is misconfigured. Return UNKNOWN
      // and let the PTransform's expand() method throw the detailed error.
      return BeamTableStatistics.BOUNDED_UNKNOWN;
    }
  }
  