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;
  import org.apache.calcite.sql.SqlKind;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.Objects;
  
  /**
   * Dynamic parameter reference in a row-expression.
   */
  public class RexDynamicParam extends RexVariable {
    //~ Instance fields --------------------------------------------------------
  
    private final int index;
  
    //~ Constructors -----------------------------------------------------------
  
    /**
     * Creates a dynamic parameter.
     *
     * @param type  inferred type of parameter
     * @param index 0-based index of dynamic parameter in statement
     */
    public RexDynamicParam(
        RelDataType type,
        int index) {
      super("?" + index, type);
      this.index = index;
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public SqlKind getKind() {
      return SqlKind.DYNAMIC_PARAM;
    }
  
    public int getIndex() {
      return index;
    }
  
    @Override public <R> R accept(RexVisitor<R> visitor) {
      return visitor.visitDynamicParam(this);
    }
  
    @Override public <R, P> R accept(RexBiVisitor<R, P> visitor, P arg) {
      return visitor.visitDynamicParam(this, arg);
    }
  
    @Override public boolean equals(@Nullable Object obj) {
      return this == obj
          || obj instanceof RexDynamicParam
          && type.equals(((RexDynamicParam) obj).type)
          && index == ((RexDynamicParam) obj).index;
    }
  
    @Override public int hashCode() {
      return Objects.hash(type, index);
    }
  }
  