/**
 * 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.tajo.plan.expr;

import org.apache.tajo.datum.Datum;

/**
 * ValueSetEval is an abstract class to represent both {@link RowConstantEval} and {@link SubqueryEval}.
 * This is allowed only for the right child of {@link InEval}.
 */
public abstract class ValueSetEval extends EvalNode implements Cloneable {

  public ValueSetEval(EvalType evalType) {
    super(evalType);
  }

  public abstract Datum[] getValues();

  @Override
  public int childNum() {
    return 0;
  }

  @Override
  public EvalNode getChild(int idx) {
    return null;
  }

  @Override
  public void preOrder(EvalNodeVisitor visitor) {
    visitor.visit(this);
  }

  @Override
  public void postOrder(EvalNodeVisitor visitor) {
    visitor.visit(this);
  }
}