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.rel.type.RelDataType;
  
  /**
   * Shuttle which creates a deep copy of a Rex expression.
   *
   * <p>This is useful when copying objects from one type factory or builder to
   * another.
   *
   * @see RexBuilder#copy(RexNode)
   */
  class RexCopier extends RexShuttle {
    //~ Instance fields --------------------------------------------------------
  
    private final RexBuilder builder;
  
    //~ Constructors -----------------------------------------------------------
  
    /**
     * Creates a RexCopier.
     *
     * @param builder Builder
     */
    RexCopier(RexBuilder builder) {
      this.builder = builder;
    }
  
    //~ Methods ----------------------------------------------------------------
  
    private RelDataType copy(RelDataType type) {
      return builder.getTypeFactory().copyType(type);
    }
  
    @Override public RexNode visitOver(RexOver over) {
      final boolean[] update = null;
      return new RexOver(copy(over.getType()), over.getAggOperator(),
          visitList(over.getOperands(), update), visitWindow(over.getWindow()),
          over.isDistinct(), over.ignoreNulls());
    }
  
    @Override public RexNode visitCall(final RexCall call) {
      final boolean[] update = null;
      return builder.makeCall(call.getParserPosition(), copy(call.getType()),
          call.getOperator(),
          visitList(call.getOperands(), update));
    }
  
    @Override public RexNode visitCorrelVariable(RexCorrelVariable variable) {
      return builder.makeCorrel(copy(variable.getType()), variable.id);
    }
  
    @Override public RexNode visitFieldAccess(RexFieldAccess fieldAccess) {
      return builder.makeFieldAccess(fieldAccess.getReferenceExpr().accept(this),
          fieldAccess.getField().getIndex());
    }
  
    @Override public RexNode visitInputRef(RexInputRef inputRef) {
      return builder.makeInputRef(copy(inputRef.getType()), inputRef.getIndex());
    }
  
    @Override public RexNode visitLocalRef(RexLocalRef localRef) {
      return new RexLocalRef(localRef.getIndex(), copy(localRef.getType()));
    }
  
    @Override public RexNode visitLiteral(RexLiteral literal) {
      // Get the value as is
      return new RexLiteral(RexLiteral.value(literal), copy(literal.getType()),
          literal.getTypeName());
    }
  
    @Override public RexNode visitDynamicParam(RexDynamicParam dynamicParam) {
      return builder.makeDynamicParam(copy(dynamicParam.getType()),
          dynamicParam.getIndex());
    }
  
    @Override public RexNode visitRangeRef(RexRangeRef rangeRef) {
      return builder.makeRangeReference(copy(rangeRef.getType()),
          rangeRef.getOffset(), false);
    }
  }
  