org.drools.core.base.accumulators.BigDecimalAverageAccumulateFunction 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;
import java.io.Serializable;
import java.math.BigDecimal;
/**
* An implementation of an accumulator capable of calculating average values
*/
public class BigDecimalAverageAccumulateFunction extends AbstractAccumulateFunction {
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
}
public void writeExternal(ObjectOutput out) throws IOException {
}
public static class AverageData implements Externalizable {
public int count = 0;
public BigDecimal total = BigDecimal.ZERO;
public AverageData() {}
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
count = in.readInt();
total = (BigDecimal) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeInt(count);
out.writeObject(total);
}
}
/* (non-Javadoc)
* @see org.kie.base.accumulators.AccumulateFunction#createContext()
*/
public AverageData createContext() {
return new AverageData();
}
/* (non-Javadoc)
* @see org.kie.base.accumulators.AccumulateFunction#init(java.lang.Object)
*/
public void init(AverageData data) {
data.count = 0;
data.total = BigDecimal.ZERO;
}
/* (non-Javadoc)
* @see org.kie.base.accumulators.AccumulateFunction#accumulate(java.lang.Object, java.lang.Object)
*/
public void accumulate(AverageData data,
Object value) {
if (value != null) {
data.count++;
data.total = data.total.add( (BigDecimal) value );
}
}
/* (non-Javadoc)
* @see org.kie.base.accumulators.AccumulateFunction#reverse(java.lang.Object, java.lang.Object)
*/
public void reverse(AverageData data,
Object value) {
if (value != null) {
data.count--;
data.total = data.total.subtract( (BigDecimal) value );
}
}
/* (non-Javadoc)
* @see org.kie.base.accumulators.AccumulateFunction#getResult(java.lang.Object)
*/
public Object getResult(AverageData data) {
return data.count == 0 ? BigDecimal.ZERO : data.total.divide( BigDecimal.valueOf( data.count ) );
}
/* (non-Javadoc)
* @see org.kie.base.accumulators.AccumulateFunction#supportsReverse()
*/
public boolean supportsReverse() {
return true;
}
/**
* {@inheritDoc}
*/
public Class< ? > getResultType() {
return BigDecimal.class;
}
}