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   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.bluetooth.bluez.internal;
  14
  15 import java.util.concurrent.CompletableFuture;
  16 import java.util.concurrent.ScheduledExecutorService;
  17 import java.util.concurrent.TimeUnit;
  18 import java.util.concurrent.atomic.AtomicInteger;
  19
  20 import org.eclipse.jdt.annotation.NonNullByDefault;
  21 import org.eclipse.jdt.annotation.Nullable;
  22 import org.freedesktop.dbus.exceptions.DBusException;
  23 import org.openhab.binding.bluetooth.util.RetryException;
  24 import org.openhab.binding.bluetooth.util.RetryFuture;
  25 import org.openhab.core.common.ThreadPoolManager;
  26 import org.osgi.service.component.annotations.Activate;
  27 import org.osgi.service.component.annotations.Component;
  28 import org.osgi.service.component.annotations.Deactivate;
  29 import org.slf4j.Logger;
  30 import org.slf4j.LoggerFactory;
  31
  32 import com.github.hypfvieh.bluetooth.DeviceManager;
  33
  34 /**
  35  * This service handles the lifecycle of the {@link DeviceManager} singleton instance.
  36  * In addition, this class is responsible for managing the BlueZPropertiesChangedHandler instance
  37  * used by the binding for listening and dispatching dbus events from the DeviceManager.
  38  *
  39  * Creation of the DeviceManagerWrapper is asynchronous and thus attempts to retrieve the
  40  * DeviceManagerWrapper through 'getDeviceManager' may initially fail.
  41  *
  42  * @author Connor Petty - Initial Contribution
  43  *
  44  */
  45 @NonNullByDefault
  46 @Component(service = DeviceManagerFactory.class)
  47 public class DeviceManagerFactory {
  48
  49     private final Logger logger = LoggerFactory.getLogger(DeviceManagerFactory.class);
  50     private final ScheduledExecutorService scheduler = ThreadPoolManager.getScheduledPool("bluetooth");
  51
  52     private final BlueZPropertiesChangedHandler changeHandler = new BlueZPropertiesChangedHandler();
  53
  54     private @Nullable CompletableFuture<DeviceManager> deviceManagerFuture;
  55     private @Nullable CompletableFuture<DeviceManagerWrapper> deviceManagerWrapperFuture;
  56
  57     public BlueZPropertiesChangedHandler getPropertiesChangedHandler() {
  58         return changeHandler;
  59     }
  60
  61     public @Nullable DeviceManagerWrapper getDeviceManager() {
  62         // we can cheat the null checker with casting here
  63         var future = (CompletableFuture<@Nullable DeviceManagerWrapper>) deviceManagerWrapperFuture;
  64         if (future != null) {
  65             return future.getNow(null);
  66         }
  67         return null;
  68     }
  69
  70     @Activate
  71     public void initialize() {
  72         logger.debug("initializing DeviceManagerFactory");
  73
  74         var stage1 = this.deviceManagerFuture = RetryFuture.callWithRetry(() -> {
  75             try {
  76                 // if this is the first call to the library, this call
  77                 // should throw an exception (that we are catching)
  78                 return DeviceManager.getInstance();
  79                 // Experimental - seems reuse does not work
  80             } catch (IllegalStateException e) {
  81                 // Exception caused by first call to the library
  82                 return DeviceManager.createInstance(false);
  83             }
  84         }, scheduler);
  85
  86         this.deviceManagerWrapperFuture = stage1.thenCompose(devManager -> {
  87             // lambdas can't modify outside variables due to scoping, so instead we use an AtomicInteger.
  88             AtomicInteger tryCount = new AtomicInteger();
  89             return RetryFuture.callWithRetry(() -> {
  90                 int count = tryCount.incrementAndGet();
  91                 try {
  92                     logger.debug("Registering property handler attempt: {}", count);
  93                     devManager.registerPropertyHandler(changeHandler);
  94                     logger.debug("Successfully registered property handler");
  95                     return new DeviceManagerWrapper(devManager);
  96                 } catch (DBusException e) {
  97                     if (count < 3) {
  98                         throw new RetryException(5, TimeUnit.SECONDS);
  99                     } else {
 100                         throw e;
 101                     }
 102                 }
 103             }, scheduler);
 104         }).whenComplete((devManagerWrapper, th) -> {
 105             if (th != null) {
 106                 logger.warn("Failed to initialize DeviceManager: {}", th.getMessage());
 107             }
 108         });
 109     }
 110
 111     @Deactivate
 112     public void dispose() {
 113         var stage1 = this.deviceManagerFuture;
 114         if (stage1 != null) {
 115             if (!stage1.cancel(true)) {
 116                 // a failure to cancel means that the stage completed normally
 117                 stage1.thenAccept(DeviceManager::closeConnection);
 118             }
 119         }
 120         this.deviceManagerFuture = null;
 121
 122         var stage2 = this.deviceManagerWrapperFuture;
 123         if (stage2 != null) {
 124             stage2.cancel(true);
 125         }
 126         this.deviceManagerWrapperFuture = null;
 127     }
 128 }