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.test.catalog;
  
  import org.apache.calcite.plan.RelOptTable;
  import org.apache.calcite.rex.RexNode;
  import org.apache.calcite.schema.ColumnStrategy;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.parser.SqlParser;
  import org.apache.calcite.sql2rel.InitializerContext;
  import org.apache.calcite.sql2rel.NullInitializerExpressionFactory;
  
  /** Define column strategies for the "VIRTUALCOLUMNS" table. */
  public class VirtualColumnsExpressionFactory extends NullInitializerExpressionFactory {
    @Override public ColumnStrategy generationStrategy(RelOptTable table, int iColumn) {
      switch (iColumn) {
      case 3:
        return ColumnStrategy.STORED;
      case 4:
        return ColumnStrategy.VIRTUAL;
      default:
        return super.generationStrategy(table, iColumn);
      }
    }
  
    @Override public RexNode newColumnDefaultValue(
        RelOptTable table, int iColumn, InitializerContext context) {
      if (iColumn == 4) {
        final SqlNode node = context.parseExpression(SqlParser.Config.DEFAULT, "A + 1");
        // Actually we should validate the node with physical schema,
        // here full table schema(includes the virtual columns) also works
        // because the expression "A + 1" does not reference any virtual column.
        final SqlNode validated = context.validateExpression(table.getRowType(), node);
        return context.convertExpression(validated);
      } else {
        return super.newColumnDefaultValue(table, iColumn, context);
      }
    }
  }
  