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Swirlds is a software platform designed to build fully-distributed applications that harness the power of the cloud without servers. Now you can develop applications with fairness in decision making, speed, trust and reliability, at a fraction of the cost of traditional server-based platforms.
/*
* Copyright (C) 2016-2024 Hedera Hashgraph, LLC
*
* 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.swirlds.common.utility;
import static com.swirlds.common.formatting.StringFormattingUtils.formattedList;
import java.util.ArrayDeque;
import java.util.Deque;
/**
*
* Tracks a running average of the last N long values. This class does not "forget" values based on time, it
* only cares about the last N values regardless of when they were added relative to the clock. It does not
* do any special weighting, all of the last N values are weighted equally.
*
*
*
* By design, this class is not thread safe. If thread safety is require then the caller must synchronize.
*
*/
public class LongRunningAverage {
private final Deque values;
private final int capacity;
private long runningSum;
/**
* Create an object for tracking the running average.
*
* @param capacity
* the number of recent values to include in the average
*/
public LongRunningAverage(final int capacity) {
if (capacity <= 0) {
throw new IllegalArgumentException("capacity must be non-zero positive");
}
this.values = new ArrayDeque<>(capacity);
this.capacity = capacity;
}
/**
* Add a value to the running average. Removes the oldest value from the
* running average if too many values have been observed.
*
* @param value
* the value to add
*/
public void add(final long value) {
if (values.size() == capacity) {
runningSum -= values.removeFirst();
}
values.addLast(value);
runningSum += value;
}
/**
* Get the current running average, or 0 if no values have been added.
*
* @return the current running average
*/
public long getAverage() {
if (values.isEmpty()) {
return 0;
}
return runningSum / values.size();
}
/**
* Get the number of elements currently being averaged.
*
* @return the number of elements currently being averaged
*/
public int size() {
return values.size();
}
/**
* Check if any values have been added to the running average.
*
* @return true if no values have been added, otherwise false
*/
public boolean isEmpty() {
return values.isEmpty();
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder();
sb.append(getAverage()).append(" [");
formattedList(sb, values.iterator());
sb.append("]");
return sb.toString();
}
}