org.drools.core.base.accumulators.MaxAccumulateFunction Maven / Gradle / Ivy
/*
* Copyright 2010 Red Hat, Inc. and/or its affiliates.
*
* 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 org.drools.core.base.accumulators;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
/**
* An implementation of an accumulator capable of calculating maximum values
*/
public class MaxAccumulateFunction extends AbstractAccumulateFunction {
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
}
public void writeExternal(ObjectOutput out) throws IOException {
}
protected static class MaxData implements Externalizable {
public Comparable max = null;
public MaxData() {}
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
max = (Comparable) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject(max);
}
@Override
public String toString() {
return "max";
}
}
public MaxData createContext() {
return new MaxData();
}
public void init(MaxData data) {
data.max = null;
}
public void accumulate(MaxData data,
Object value) {
if (value != null) {
data.max = data.max == null || data.max.compareTo( value ) < 0 ?
(Comparable) value :
data.max;
}
}
public void reverse(MaxData data,
Object value) {
}
public Object getResult(MaxData data) {
return data.max;
}
public boolean supportsReverse() {
return false;
}
public Class getResultType() {
return Comparable.class;
}
}