/*
 * 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.adapter.enumerable;

import org.apache.calcite.plan.Convention;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.convert.ConverterRule;
import org.apache.calcite.rel.logical.LogicalWindow;

/**
 * Rule to convert a {@link org.apache.calcite.rel.logical.LogicalWindow} to
 * an {@link org.apache.calcite.adapter.enumerable.EnumerableWindow}.
 */
class EnumerableWindowRule extends ConverterRule {
  EnumerableWindowRule() {
    super(LogicalWindow.class, Convention.NONE, EnumerableConvention.INSTANCE,
        "EnumerableWindowRule");
  }

  public RelNode convert(RelNode rel) {
    final LogicalWindow winAgg = (LogicalWindow) rel;
    final RelTraitSet traitSet =
        winAgg.getTraitSet().replace(EnumerableConvention.INSTANCE);
    final RelNode child = winAgg.getInput();
    final RelNode convertedChild =
        convert(child,
            child.getTraitSet().replace(EnumerableConvention.INSTANCE));
    return new EnumerableWindow(rel.getCluster(), traitSet, convertedChild,
        winAgg.getConstants(), winAgg.getRowType(), winAgg.groups);
  }
}
