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.schema.impl;
  
  import org.apache.calcite.config.CalciteConnectionConfig;
  import org.apache.calcite.schema.Schema;
  import org.apache.calcite.schema.Statistic;
  import org.apache.calcite.schema.Statistics;
  import org.apache.calcite.schema.Table;
  import org.apache.calcite.schema.Wrapper;
  import org.apache.calcite.sql.SqlCall;
  import org.apache.calcite.sql.SqlNode;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * Abstract base class for implementing {@link Table}.
   *
   * <p>Sub-classes should override {@link #isRolledUp} and
   * {@link Table#rolledUpColumnValidInsideAgg(String, SqlCall, SqlNode, CalciteConnectionConfig)}
   * if their table can potentially contain rolled up values. This information is
   * used by the validator to check for illegal uses of these columns.
   */
  public abstract class AbstractTable implements Table, Wrapper {
    protected AbstractTable() {
    }
  
    // Default implementation. Override if you have statistics.
    @Override public Statistic getStatistic() {
      return Statistics.UNKNOWN;
    }
  
    @Override public Schema.TableType getJdbcTableType() {
      return Schema.TableType.TABLE;
    }
  
    @Override public <C extends Object> @Nullable C unwrap(Class<C> aClass) {
      if (aClass.isInstance(this)) {
        return aClass.cast(this);
      }
      return null;
    }
  
    @Override public boolean isRolledUp(String column) {
      return false;
    }
  
    @Override public boolean rolledUpColumnValidInsideAgg(String column,
        SqlCall call, @Nullable SqlNode parent, @Nullable CalciteConnectionConfig config) {
      return true;
    }
  }
  