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.beam.sdk.extensions.sql.impl.cep;
  
  import java.io.Serializable;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.RelFieldCollation;
  
  /**
   * The {@code OrderKey} class stores the information to sort a column.
   *
   * <h3>Constraints</h3>
   *
   * <ul>
   *   <ui>Strict orders are not supported for now.
   * </ul>
   */
  public class OrderKey implements Serializable {
  
    private final int fIndex;
    private final boolean dir;
    private final boolean nullFirst;
  
    private OrderKey(int fIndex, boolean dir, boolean nullFirst) {
      this.fIndex = fIndex;
      this.dir = dir;
      this.nullFirst = nullFirst;
    }
  
    public int getIndex() {
      return fIndex;
    }
  
    public boolean getDir() {
      return dir;
    }
  
    public boolean getNullFirst() {
      return nullFirst;
    }
  
    public static OrderKey of(RelFieldCollation orderKey) {
      int fieldIndex = orderKey.getFieldIndex();
      RelFieldCollation.Direction dir = orderKey.direction;
      RelFieldCollation.NullDirection nullDir = orderKey.nullDirection;
      if (!dir.isDescending()) {
        if (nullDir == RelFieldCollation.NullDirection.FIRST) {
          return new OrderKey(fieldIndex, true, true);
        } else {
          return new OrderKey(fieldIndex, true, false);
        }
      } else {
        if (nullDir == RelFieldCollation.NullDirection.FIRST) {
          return new OrderKey(fieldIndex, false, true);
        } else {
          return new OrderKey(fieldIndex, false, false);
        }
      }
    }
  }
  