org.apache.phoenix.expression.aggregator.BaseAggregator Maven / Gradle / Ivy
/*
* 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.aggregator;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.phoenix.expression.BaseTerminalExpression;
import org.apache.phoenix.expression.visitor.ExpressionVisitor;
import org.apache.phoenix.schema.SortOrder;
import org.apache.phoenix.util.SizedUtil;
import org.apache.phoenix.thirdparty.com.google.common.base.Preconditions;
/**
* Base class for Aggregator implementations
*
*
* @since 0.1
*/
public abstract class BaseAggregator extends BaseTerminalExpression implements Aggregator {
protected final SortOrder sortOrder;
public BaseAggregator(SortOrder sortOrder) {
Preconditions.checkNotNull(sortOrder);
this.sortOrder = sortOrder;
}
@Override
public boolean isNullable() {
return true;
}
@Override
public int getSize() {
return SizedUtil.OBJECT_SIZE;
}
ImmutableBytesWritable evalClientAggs(Aggregator clientAgg) {
CountAggregator ca = (CountAggregator)clientAgg;
ImmutableBytesWritable ptr = new ImmutableBytesWritable();
ca.evaluate(null, ptr);
return ptr;
}
@Override
public T accept(ExpressionVisitor visitor) {
return null;
}
@Override
public boolean trackSize() {
return false;
}
}