org.drools.core.base.accumulators.MinAccumulateFunction 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 minimun values
*/
public class MinAccumulateFunction extends AbstractAccumulateFunction {
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
}
public void writeExternal(ObjectOutput out) throws IOException {
}
protected static class MinData implements Externalizable {
public Comparable min = null;
public MinData() {}
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
min = (Comparable) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject(min);
}
@Override
public String toString() {
return "min";
}
}
public MinData createContext() {
return new MinData();
}
public void init(MinData data) {
data.min = null;
}
public void accumulate(MinData data,
Object value) {
if (value != null) {
data.min = data.min == null || data.min.compareTo( value ) > 0 ?
(Comparable) value :
data.min;
}
}
public void reverse(MinData data,
Object value) {
}
public Object getResult(MinData data) {
return data.min;
}
public boolean supportsReverse() {
return false;
}
public Class getResultType() {
return Comparable.class;
}
}