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+/**
+ * ============LICENSE_START===================================================
+ * SPARKY (AAI UI service)
+ * ============================================================================
+ * Copyright © 2017 AT&T Intellectual Property.
+ * Copyright © 2017 Amdocs
+ * All rights reserved.
+ * ============================================================================
+ * 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.
+ * ============LICENSE_END=====================================================
+ *
+ * ECOMP and OpenECOMP are trademarks
+ * and service marks of AT&T Intellectual Property.
+ */
+
+package org.openecomp.sparky.analytics;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * TODO: Fill in description.
+ *
+ * @author davea
+ */
+public class AveragingRingBuffer {
+
+ private int numElements;
+
+ private long[] data;
+
+ private AtomicInteger index;
+
+ private long average;
+
+ private boolean initialAverageCalculated;
+
+ /**
+ * Instantiates a new averaging ring buffer.
+ *
+ * @param size the size
+ */
+ public AveragingRingBuffer(int size) {
+
+ if (size == 0) {
+ throw new IllegalArgumentException("Size must be greater than zero");
+ }
+
+ this.initialAverageCalculated = false;
+ this.numElements = size;
+ this.data = new long[this.numElements];
+ this.index = new AtomicInteger(-1);
+ }
+
+ /**
+ * Calculate average.
+ *
+ * @param maxArrayIndex the max array index
+ */
+ private void calculateAverage(int maxArrayIndex) {
+
+ long sum = 0;
+
+ for (int i = 0; i <= maxArrayIndex; i++) {
+ sum += data[i];
+ }
+
+ average = (sum / (maxArrayIndex + 1));
+
+ }
+
+ public long getAvg() {
+
+ if (!initialAverageCalculated) {
+ /*
+ * until the index rolls once we will calculate the average from the data that has been added
+ * to the array, not including the zero elements
+ */
+ if (index.get() < 0) {
+ calculateAverage(0);
+ } else {
+ calculateAverage(index.get());
+ }
+
+ }
+
+ return average;
+ }
+
+ /**
+ * Adds the sample.
+ *
+ * @param value the value
+ */
+ public synchronized void addSample(long value) {
+
+ index.incrementAndGet();
+
+ data[index.get()] = value;
+
+ if (index.get() == (numElements - 1)) {
+ calculateAverage(numElements - 1);
+
+ if (!initialAverageCalculated) {
+ initialAverageCalculated = true;
+ }
+
+ index.set(-1);
+ }
+
+ }
+
+}