Initial commit for AAI-UI(sparky-backend)

[aai/sparky-be.git] / src / main / java / org / openecomp / sparky / analytics / AveragingRingBuffer.java

diff --git a/src/main/java/org/openecomp/sparky/analytics/AveragingRingBuffer.java b/src/main/java/org/openecomp/sparky/analytics/AveragingRingBuffer.java
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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);
+    }
+
+  }
+
+}