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.calcite.piglet;
  
  import org.apache.calcite.DataContext;
  import org.apache.calcite.linq4j.Enumerable;
  import org.apache.calcite.linq4j.tree.Expressions;
  import org.apache.calcite.plan.RelOptSchema;
  import org.apache.calcite.plan.RelOptTable;
  import org.apache.calcite.prepare.RelOptTableImpl;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rel.type.RelDataTypeFactory;
  import org.apache.calcite.schema.ScannableTable;
  import org.apache.calcite.schema.Statistic;
  import org.apache.calcite.schema.Statistics;
  import org.apache.calcite.schema.impl.AbstractTable;
  
  import com.google.common.collect.ImmutableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.List;
  
  /**
   * A non-queriable table that contains only row type to represent a Pig Table. This table is used
   * for constructing Calcite logical plan from Pig DAG.
   */
  public class PigTable extends AbstractTable implements ScannableTable {
    // Dummy statistics with 10 rows for any table
    private static final Statistic DUMMY_STATISTICS = Statistics.of(10.0, ImmutableList.of());
    private final RelDataType rowType;
  
    private PigTable(RelDataType rowType) {
      this.rowType = rowType;
    }
  
    /**
     * Creates a {@link RelOptTable} for a schema only table.
     *
     * @param schema Catalog object
     * @param rowType Relational schema for the table
     * @param names Names of Pig table
     */
    public static RelOptTable createRelOptTable(RelOptSchema schema,
        RelDataType rowType, List<String> names) {
      final PigTable pigTable = new PigTable(rowType);
      return RelOptTableImpl.create(schema, rowType, names, pigTable,
          c -> Expressions.constant(Boolean.TRUE));
    }
  
    @Override public RelDataType getRowType(final RelDataTypeFactory typeFactory) {
      return rowType;
    }
  
    @Override public Statistic getStatistic() {
      return DUMMY_STATISTICS;
    }
  
    @Override public Enumerable<@Nullable Object[]> scan(final DataContext root) {
      return null;
    }
  }
  