com.hazelcast.aggregation.impl.MaxAggregator Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.aggregation.impl;
import com.hazelcast.aggregation.Aggregator;
import com.hazelcast.nio.ObjectDataInput;
import com.hazelcast.nio.ObjectDataOutput;
import com.hazelcast.nio.serialization.IdentifiedDataSerializable;
import com.hazelcast.query.impl.Comparables;
import java.io.IOException;
public final class MaxAggregator extends AbstractAggregator
implements IdentifiedDataSerializable {
private R max;
public MaxAggregator() {
super();
}
public MaxAggregator(String attributePath) {
super(attributePath);
}
@Override
public void accumulateExtracted(I entry, R value) {
if (isCurrentlyLessThan(value)) {
max = value;
}
}
private boolean isCurrentlyLessThan(R otherValue) {
if (otherValue == null) {
return false;
}
return max == null || Comparables.compare(max, otherValue) < 0;
}
@SuppressWarnings("unchecked")
@Override
public void combine(Aggregator aggregator) {
MaxAggregator maxAggregator = (MaxAggregator) aggregator;
R valueFromOtherAggregator = (R) maxAggregator.max;
if (isCurrentlyLessThan(valueFromOtherAggregator)) {
this.max = valueFromOtherAggregator;
}
}
@Override
public R aggregate() {
return max;
}
@Override
public int getFactoryId() {
return AggregatorDataSerializerHook.F_ID;
}
@Override
public int getId() {
return AggregatorDataSerializerHook.MAX;
}
@Override
public void writeData(ObjectDataOutput out) throws IOException {
out.writeUTF(attributePath);
out.writeObject(max);
}
@Override
public void readData(ObjectDataInput in) throws IOException {
this.attributePath = in.readUTF();
this.max = in.readObject();
}
}