/*******************************************************************************
* Copyright (c) 2013, Salesforce.com, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* Neither the name of Salesforce.com nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
******************************************************************************/
package com.salesforce.phoenix.expression.function;
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import com.salesforce.phoenix.expression.Expression;
import com.salesforce.phoenix.expression.aggregator.Aggregator;
import com.salesforce.phoenix.expression.aggregator.MinAggregator;
import com.salesforce.phoenix.parse.FunctionParseNode.Argument;
import com.salesforce.phoenix.parse.FunctionParseNode.BuiltInFunction;
import com.salesforce.phoenix.parse.MinAggregateParseNode;
import com.salesforce.phoenix.schema.ColumnModifier;
import com.salesforce.phoenix.schema.PDataType;
import com.salesforce.phoenix.schema.tuple.Tuple;
/**
* Built-in function for finding MIN.
*
* @author syyang
* @since 0.1
*/
@BuiltInFunction(name=MinAggregateFunction.NAME, nodeClass=MinAggregateParseNode.class, args= {@Argument()} )
public class MinAggregateFunction extends DelegateConstantToCountAggregateFunction {
public static final String NAME = "MIN";
public MinAggregateFunction() {
}
public MinAggregateFunction(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 Aggregator newServerAggregator(Configuration conf) {
final PDataType type = getAggregatorExpression().getDataType();
ColumnModifier columnModifier = getAggregatorExpression().getColumnModifier();
return new MinAggregator(columnModifier) {
@Override
public PDataType getDataType() {
return type;
}
};
}
@Override
public ColumnModifier getColumnModifier() {
return getAggregatorExpression().getColumnModifier();
}
@Override
public String getName() {
return NAME;
}
}