/*
 * 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.phoenix.expression.function;

import java.util.List;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.phoenix.expression.Expression;
import org.apache.phoenix.schema.tuple.Tuple;
import org.apache.phoenix.schema.types.PDataType;

/**
 * (FIRST|LAST|NTH)_VALUE build in function interface
 */
abstract public class FirstLastValueBaseFunction extends DelegateConstantToCountAggregateFunction {

  public FirstLastValueBaseFunction() {
  }

  public FirstLastValueBaseFunction(List<Expression> childExpressions,
    CountAggregateFunction delegate) {
    super(childExpressions, delegate);
  }

  @Override
  public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
    boolean wasEvaluated = super.evaluate(tuple, ptr);
    if (!wasEvaluated) {
      return false;
    }
    if (isConstantExpression()) {
      getAggregatorExpression().evaluate(tuple, ptr);
    }
    return true;
  }

  @Override
  public PDataType getDataType() {
    return children.get(2).getDataType();
  }

  @Override
  public Integer getMaxLength() {
    return children.get(2).getMaxLength();
  }

  @Override
  public Integer getScale() {
    return children.get(2).getScale();
  }
}
