git.basschouten.com Git - openhab-addons.git/blob

   1 /**
   2  * Copyright (c) 2010-2021 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.mqtt.discovery;
  14
  15 import java.util.Date;
  16 import java.util.Set;
  17 import java.util.concurrent.ScheduledFuture;
  18 import java.util.concurrent.TimeUnit;
  19
  20 import org.eclipse.jdt.annotation.NonNullByDefault;
  21 import org.eclipse.jdt.annotation.Nullable;
  22 import org.openhab.core.config.discovery.AbstractDiscoveryService;
  23 import org.openhab.core.thing.ThingTypeUID;
  24 import org.slf4j.Logger;
  25 import org.slf4j.LoggerFactory;
  26
  27 /**
  28  * Base MQTT discovery class. Responsible for connecting to the {@link MQTTTopicDiscoveryService}.
  29  *
  30  * Implement MQTT discovery services on top of this. You still need to reference
  31  * the MQTTTopicDiscoveryService like in:
  32  *
  33  * <pre>
  34  * &#64;NonNullByDefault({})
  35  * &#64;Reference
  36  * protected MQTTTopicDiscoveryService mqttTopicDiscovery;
  37  * </pre>
  38  *
  39  * @author David Graeff - Initial contribution
  40  */
  41 @NonNullByDefault
  42 public abstract class AbstractMQTTDiscovery extends AbstractDiscoveryService implements MQTTTopicDiscoveryParticipant {
  43     private final Logger logger = LoggerFactory.getLogger(AbstractMQTTDiscovery.class);
  44
  45     protected final String subscribeTopic;
  46
  47     private int timeout;
  48
  49     private @Nullable ScheduledFuture<?> scheduledStop;
  50
  51     public AbstractMQTTDiscovery(@Nullable Set<ThingTypeUID> supportedThingTypes, int timeout,
  52             boolean backgroundDiscoveryEnabledByDefault, String baseTopic) {
  53         super(supportedThingTypes, 0, backgroundDiscoveryEnabledByDefault);
  54         this.subscribeTopic = baseTopic;
  55         this.timeout = timeout;
  56     }
  57
  58     /**
  59      * Return the topic discovery service.
  60      */
  61     protected abstract MQTTTopicDiscoveryService getDiscoveryService();
  62
  63     private synchronized void stopTimeout() {
  64         if (scheduledStop != null) {
  65             scheduledStop.cancel(false);
  66             scheduledStop = null;
  67         }
  68     }
  69
  70     protected synchronized void resetTimeout() {
  71         stopTimeout();
  72
  73         // schedule an automatic call of stopScan when timeout is reached
  74         if (timeout > 0) {
  75             Runnable runnable = new Runnable() {
  76                 @Override
  77                 public void run() {
  78                     try {
  79                         stopScan();
  80                     } catch (Exception e) {
  81                         logger.debug("Exception occurred during execution: {}", e.getMessage(), e);
  82                     }
  83                 }
  84             };
  85
  86             scheduledStop = scheduler.schedule(runnable, timeout, TimeUnit.SECONDS);
  87         }
  88     }
  89
  90     @Override
  91     protected void startScan() {
  92         if (isBackgroundDiscoveryEnabled()) {
  93             super.stopScan();
  94             return;
  95         }
  96         resetTimeout();
  97         getDiscoveryService().subscribe(this, subscribeTopic);
  98     }
  99
 100     @Override
 101     protected synchronized void stopScan() {
 102         if (isBackgroundDiscoveryEnabled()) {
 103             super.stopScan();
 104             return;
 105         }
 106         stopTimeout();
 107         getDiscoveryService().unsubscribe(this);
 108         super.stopScan();
 109     }
 110
 111     @Override
 112     public synchronized void abortScan() {
 113         stopTimeout();
 114         super.abortScan();
 115     }
 116
 117     @Override
 118     protected void startBackgroundDiscovery() {
 119         // Remove results that are restored after a restart
 120         removeOlderResults(new Date().getTime());
 121         getDiscoveryService().subscribe(this, subscribeTopic);
 122     }
 123
 124     @Override
 125     protected void stopBackgroundDiscovery() {
 126         getDiscoveryService().unsubscribe(this);
 127     }
 128 }