org.codelibs.elasticsearch.taste.common.RunningAverage 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.codelibs.elasticsearch.taste.common;
/**
*
* Interface for classes that can keep track of a running average of a series of numbers. One can add to or
* remove from the series, as well as update a datum in the series. The class does not actually keep track of
* the series of values, just its running average, so it doesn't even matter if you remove/change a value that
* wasn't added.
*
*/
public interface RunningAverage {
/**
* @param datum
* new item to add to the running average
* @throws IllegalArgumentException
* if datum is {@link Double#NaN}
*/
void addDatum(double datum);
/**
* @param datum
* item to remove to the running average
* @throws IllegalArgumentException
* if datum is {@link Double#NaN}
* @throws IllegalStateException
* if count is 0
*/
void removeDatum(double datum);
/**
* @param delta
* amount by which to change a datum in the running average
* @throws IllegalArgumentException
* if delta is {@link Double#NaN}
* @throws IllegalStateException
* if count is 0
*/
void changeDatum(double delta);
int getCount();
double getAverage();
/**
* @return a (possibly immutable) object whose average is the negative of this object's
*/
RunningAverage inverse();
}