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.rex;
  
  import org.apache.calcite.util.Permutation;
  
  /**
   * Visitor which replaces {@link RexLocalRef} objects after the expressions in a
   * {@link RexProgram} have been reordered.
   *
   * @see RexPermuteInputsShuttle
   */
  public class RexPermutationShuttle extends RexShuttle {
    //~ Instance fields --------------------------------------------------------
  
    private final Permutation permutation;
  
    //~ Constructors -----------------------------------------------------------
  
    public RexPermutationShuttle(Permutation permutation) {
      this.permutation = permutation;
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public RexNode visitLocalRef(RexLocalRef local) {
      final int index = local.getIndex();
      int target = permutation.getTarget(index);
      return new RexLocalRef(
          target,
          local.getType());
    }
  }
  