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   1 /**
   2  * Copyright (c) 2010-2023 Contributors to the openHAB project
   3  *
   4  * See the NOTICE file(s) distributed with this work for additional
   5  * information.
   6  *
   7  * This program and the accompanying materials are made available under the
   8  * terms of the Eclipse Public License 2.0 which is available at
   9  * http://www.eclipse.org/legal/epl-2.0
  10  *
  11  * SPDX-License-Identifier: EPL-2.0
  12  */
  13 package org.openhab.binding.jeelink.internal;
  14
  15 import java.util.concurrent.ScheduledExecutorService;
  16 import java.util.concurrent.ScheduledFuture;
  17 import java.util.concurrent.TimeUnit;
  18
  19 /**
  20  * Computes a rolling average of readings that is passed on to the next publisher
  21  * after a given time frame.
  22  *
  23  * @author Volker Bier - Initial contribution
  24  */
  25 public abstract class RollingAveragePublisher<R extends Reading> implements ReadingPublisher<R> {
  26     private final ReadingPublisher<R> publisher;
  27
  28     private ScheduledFuture<?> valueUpdateJob;
  29     private RollingReadingAverage<R> rollingAvg;
  30
  31     public RollingAveragePublisher(int bufferSize, int interval, ReadingPublisher<R> p,
  32             ScheduledExecutorService execService) {
  33         publisher = p;
  34
  35         valueUpdateJob = createUpdateJob(execService, interval);
  36         rollingAvg = createRollingReadingAverage(bufferSize);
  37     }
  38
  39     public abstract RollingReadingAverage<R> createRollingReadingAverage(int bufferSize);
  40
  41     @Override
  42     public void publish(R reading) {
  43         rollingAvg.add(reading);
  44     }
  45
  46     @Override
  47     public void dispose() {
  48         if (valueUpdateJob != null) {
  49             valueUpdateJob.cancel(true);
  50             valueUpdateJob = null;
  51         }
  52
  53         publisher.dispose();
  54     }
  55
  56     private ScheduledFuture<?> createUpdateJob(ScheduledExecutorService execService, final int updateInterval) {
  57         return execService.scheduleWithFixedDelay(() -> {
  58             publisher.publish(rollingAvg.getAverage());
  59         }, updateInterval, updateInterval, TimeUnit.SECONDS);
  60     }
  61 }