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/*
 * 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 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();
    }
}