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.sql.validate;
  
  import org.apache.calcite.sql.SqlCall;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.util.Litmus;
  import org.apache.calcite.util.Pair;
  
  import java.util.List;
  
  /**
   * The name-resolution scope of a OVER clause. The objects visible are those in
   * the parameters found on the left side of the over clause, and objects
   * inherited from the parent scope.
   *
   * <p>This object is both a {@link SqlValidatorScope} only. In the query
   *
   * <blockquote>
   * <pre>SELECT name FROM (
   *     SELECT *
   *     FROM emp OVER (
   *         ORDER BY empno
   *         RANGE BETWEEN 2 PRECEDING AND 2 FOLLOWING))
   * </pre>
   * </blockquote>
   *
   * <p>We need to use the {@link OverScope} as a {@link SqlValidatorNamespace}
   * when resolving names used in the window specification.
   */
  public class OverScope extends ListScope {
    //~ Instance fields --------------------------------------------------------
  
    private final SqlCall overCall;
  
    //~ Constructors -----------------------------------------------------------
  
    /**
     * Creates a scope corresponding to a SELECT clause.
     *
     * @param parent   Parent scope, or null
     * @param overCall Call to OVER operator
     */
    OverScope(
        SqlValidatorScope parent,
        SqlCall overCall) {
      super(parent);
      this.overCall = overCall;
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public SqlNode getNode() {
      return overCall;
    }
  
    @Override public SqlMonotonicity getMonotonicity(SqlNode expr) {
      SqlMonotonicity monotonicity = expr.getMonotonicity(this);
      if (monotonicity != SqlMonotonicity.NOT_MONOTONIC) {
        return monotonicity;
      }
  
      if (children.size() == 1) {
        final SqlValidatorNamespace child = children.get(0).namespace;
        final List<Pair<SqlNode, SqlMonotonicity>> monotonicExprs =
            child.getMonotonicExprs();
        for (Pair<SqlNode, SqlMonotonicity> pair : monotonicExprs) {
          if (expr.equalsDeep(pair.left, Litmus.IGNORE)) {
            return pair.right;
          }
        }
      }
      return super.getMonotonicity(expr);
    }
  }
  