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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.linuxinput.internal;
  14
  15 import java.io.IOException;
  16 import java.util.concurrent.CancellationException;
  17
  18 import org.eclipse.jdt.annotation.NonNullByDefault;
  19 import org.eclipse.jdt.annotation.Nullable;
  20 import org.openhab.core.thing.Thing;
  21 import org.openhab.core.thing.ThingStatus;
  22 import org.openhab.core.thing.ThingStatusDetail;
  23 import org.openhab.core.thing.binding.BaseThingHandler;
  24 import org.slf4j.Logger;
  25 import org.slf4j.LoggerFactory;
  26
  27 /**
  28  * Abstract handler, that encapsulates the lifecycle of an underlying device.
  29  *
  30  * @author Thomas Weißschuh - Initial contribution
  31  */
  32 @NonNullByDefault
  33 public abstract class DeviceReadingHandler extends BaseThingHandler {
  34     private final Logger logger = LoggerFactory.getLogger(DeviceReadingHandler.class);
  35
  36     private @Nullable Thread worker = null;
  37
  38     public DeviceReadingHandler(Thing thing) {
  39         super(thing);
  40     }
  41
  42     abstract boolean immediateSetup() throws IOException;
  43
  44     abstract boolean delayedSetup() throws IOException;
  45
  46     abstract void handleEventsInThread() throws IOException;
  47
  48     abstract void closeDevice() throws IOException;
  49
  50     abstract String getInstanceName();
  51
  52     @Override
  53     public final void initialize() {
  54         boolean performDelayedSetup = performImmediateSetup();
  55         if (performDelayedSetup) {
  56             scheduler.execute(() -> {
  57                 boolean handleEvents = performDelayedSetup();
  58                 if (handleEvents) {
  59                     Thread thread = Utils.backgroundThread(() -> {
  60                         try {
  61                             handleEventsInThread();
  62                         } catch (IOException e) {
  63                             logger.warn("Could not read event", e);
  64                             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.COMMUNICATION_ERROR, e.getMessage());
  65                         }
  66                     }, "events", thing);
  67                     thread.start();
  68                     worker = thread;
  69                 }
  70             });
  71         }
  72     }
  73
  74     private boolean performImmediateSetup() {
  75         try {
  76             return immediateSetup();
  77         } catch (IOException e) {
  78             handleSetupError(e);
  79             return false;
  80         }
  81     }
  82
  83     private boolean performDelayedSetup() {
  84         try {
  85             return delayedSetup();
  86         } catch (IOException e) {
  87             handleSetupError(e);
  88             return false;
  89         }
  90     }
  91
  92     private void handleSetupError(Exception e) {
  93         updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.CONFIGURATION_ERROR, e.getMessage());
  94     }
  95
  96     @Override
  97     public final void dispose() {
  98         try {
  99             stopWorker();
 100         } catch (InterruptedException e) {
 101             Thread.currentThread().interrupt();
 102         } finally {
 103             try {
 104                 closeDevice();
 105             } catch (IOException e) {
 106                 logger.debug("Could not close device", e);
 107             }
 108             logger.trace("disposed");
 109         }
 110     }
 111
 112     private void stopWorker() throws InterruptedException {
 113         @Nullable
 114         Thread activeWorker = this.worker;
 115         logger.debug("interrupting worker {}", activeWorker);
 116         worker = null;
 117
 118         if (activeWorker == null) {
 119             return;
 120         }
 121         activeWorker.interrupt();
 122         try {
 123             activeWorker.join(100);
 124         } catch (CancellationException e) {
 125             /* expected */
 126         }
 127         logger.debug("worker interrupted");
 128         if (activeWorker.isAlive()) {
 129             logger.warn("Worker not stopped");
 130         }
 131     }
 132 }