Add callback mechanism into LwM2mClientObserver for when the unexpected error occurred

leshan-client-cf/src/main/java/org/eclipse/leshan/client/californium/LeshanClient.java

@@ -38,6 +38,7 @@
 import org.eclipse.leshan.client.engine.RegistrationEngine;
 import org.eclipse.leshan.client.engine.RegistrationEngineFactory;
 import org.eclipse.leshan.client.observer.LwM2mClientObserver;
+import org.eclipse.leshan.client.observer.LwM2mClientObserverAdapter;
 import org.eclipse.leshan.client.observer.LwM2mClientObserverDispatcher;
 import org.eclipse.leshan.client.resource.LwM2mObjectEnabler;
 import org.eclipse.leshan.client.resource.LwM2mObjectTree;
@@ -115,6 +116,9 @@ public LeshanClient(String endpoint, InetSocketAddress localAddress,
         createRegistrationUpdateHandler(engine, endpointsManager, bootstrapHandler, objectTree);
 
         coapApi = new CoapAPI();
+
+        // register the shutdown observer for when the unexpected error occurred.
+        addObserver(new ShutdownOnUnexpectedErrorObserver(this));
     }
 
     protected LwM2mObjectTree createObjectTree(List<? extends LwM2mObjectEnabler> objectEnablers) {
@@ -320,4 +324,18 @@ public Map<String, ServerIdentity> getRegisteredServers() {
     public InetSocketAddress getAddress(ServerIdentity server) {
         return endpointsManager.getEndpoint(server).getAddress();
     }
+
+    private static class ShutdownOnUnexpectedErrorObserver extends LwM2mClientObserverAdapter {
+        final LeshanClient client;
+
+        public ShutdownOnUnexpectedErrorObserver(final LeshanClient client) {
+            this.client = client;
+        }
+
+        @Override
+        public void onUnexpectedError(Throwable unexpectedError) {
+            LOG.error("unexpected error occurred. destroy the leshan-client", unexpectedError);
+            client.destroy(true);
+        }
+    }
 }

leshan-client-core/src/main/java/org/eclipse/leshan/client/engine/DefaultRegistrationEngine.java

@@ -526,6 +526,7 @@ public void run() {
                     LOG.info("Bootstrap task interrupted. ");
                 } catch (RuntimeException e) {
                     LOG.error("Unexpected exception during bootstrap task", e);
+                    observer.onUnexpectedError(e);
                 }
             }
         }
@@ -564,6 +565,7 @@ public void run() {
                     LOG.info("Registration task interrupted. ");
                 } catch (RuntimeException e) {
                     LOG.error("Unexpected exception during registration task", e);
+                    observer.onUnexpectedError(e);
                 }
             }
         }
@@ -612,6 +614,7 @@ public void run() {
                     LOG.info("Registration update task interrupted.");
                 } catch (RuntimeException e) {
                     LOG.error("Unexpected exception during update registration task", e);
+                    observer.onUnexpectedError(e);
                 }
             }
         }

leshan-client-core/src/main/java/org/eclipse/leshan/client/observer/LwM2mClientObserver.java

@@ -69,4 +69,8 @@ void onDeregistrationFailure(ServerIdentity server, DeregisterRequest request, R
             String errorMessage, Exception cause);
 
     void onDeregistrationTimeout(ServerIdentity server, DeregisterRequest request);
+
+    // ============== Unexpected Error Handling =================
+
+    void onUnexpectedError(Throwable unexpectedError);
 }

leshan-client-core/src/main/java/org/eclipse/leshan/client/observer/LwM2mClientObserverAdapter.java

@@ -95,4 +95,8 @@ public void onDeregistrationFailure(ServerIdentity server, DeregisterRequest req
     @Override
     public void onDeregistrationTimeout(ServerIdentity server, DeregisterRequest request) {
     }
+
+    @Override
+    public void onUnexpectedError(Throwable unexpectedError) {
+    }
 }

leshan-client-core/src/main/java/org/eclipse/leshan/client/observer/LwM2mClientObserverDispatcher.java

@@ -151,4 +151,10 @@ public void onDeregistrationTimeout(ServerIdentity server, DeregisterRequest req
         }
     }
 
+    @Override
+    public void onUnexpectedError(Throwable unexpectedError) {
+        for (LwM2mClientObserver observer : observers) {
+            observer.onUnexpectedError(unexpectedError);
+        }
+    }
 }

leshan-client-core/src/main/java/org/eclipse/leshan/client/resource/LwM2mInstanceEnabler.java

@@ -22,6 +22,9 @@
 
 import org.eclipse.leshan.client.LwM2mClient;
 import org.eclipse.leshan.client.servers.ServerIdentity;
+import org.eclipse.leshan.core.Destroyable;
+import org.eclipse.leshan.core.Startable;
+import org.eclipse.leshan.core.Stoppable;
 import org.eclipse.leshan.core.model.ObjectModel;
 import org.eclipse.leshan.core.node.LwM2mObjectInstance;
 import org.eclipse.leshan.core.node.LwM2mResource;
@@ -45,6 +48,12 @@
  * <p>
  * Implementations of this interface should adhere to the definition of the implemented LWM2M Object type regarding
  * acceptable resource IDs for the <code>read, write</code> and <code>execute</code> methods.
+ * An instance that implements this interface synchronizes with the lifecycle of the LeshanClient. This means when
+ * <p>
+ * {@code LeshanClient#destroy()} is called, {@code LwM2mInstanceEnabler#destroy()} is also called if it implements the
+ * {@link Destroyable} interface. And {@link Startable} ({@code #start()}) and {@link Stoppable} ({@code #stop()}) are
+ * also same as this. If you need to restart the instance, please implement {@link Startable} with {@link Stoppable}
+ * together.
  */
 public interface LwM2mInstanceEnabler {
 

leshan-client-core/src/main/java/org/eclipse/leshan/client/resource/ObjectEnabler.java

@@ -28,7 +28,10 @@
 import org.eclipse.leshan.client.LwM2mClient;
 import org.eclipse.leshan.client.servers.ServerIdentity;
 import org.eclipse.leshan.client.servers.ServersInfoExtractor;
+import org.eclipse.leshan.core.Destroyable;
 import org.eclipse.leshan.core.LwM2mId;
+import org.eclipse.leshan.core.Startable;
+import org.eclipse.leshan.core.Stoppable;
 import org.eclipse.leshan.core.model.ObjectModel;
 import org.eclipse.leshan.core.node.LwM2mObject;
 import org.eclipse.leshan.core.node.LwM2mObjectInstance;
@@ -62,7 +65,7 @@
  * Implementing a {@link LwM2mInstanceEnabler} then creating an {@link ObjectEnabler} with {@link ObjectsInitializer} is
  * the easier way to implement LWM2M object in Leshan client.
  */
-public class ObjectEnabler extends BaseObjectEnabler {
+public class ObjectEnabler extends BaseObjectEnabler implements Destroyable, Startable, Stoppable {
 
     protected Map<Integer, LwM2mInstanceEnabler> instances;
     protected LwM2mInstanceEnablerFactory instanceFactory;
@@ -411,4 +414,33 @@ public void setLwM2mClient(LwM2mClient client) {
             instanceEnabler.setLwM2mClient(client);
         }
     }
+
+    @Override
+    public void destroy() {
+        for (LwM2mInstanceEnabler instanceEnabler : instances.values()) {
+            if (instanceEnabler instanceof Destroyable) {
+                ((Destroyable) instanceEnabler).destroy();
+            } else if (instanceEnabler instanceof Stoppable) {
+                ((Stoppable) instanceEnabler).stop();
+            }
+        }
+    }
+
+    @Override
+    public void start() {
+        for (LwM2mInstanceEnabler instanceEnabler : instances.values()) {
+            if (instanceEnabler instanceof Startable) {
+                ((Startable) instanceEnabler).start();
+            }
+        }
+    }
+
+    @Override
+    public void stop() {
+        for (LwM2mInstanceEnabler instanceEnabler : instances.values()) {
+            if (instanceEnabler instanceof Stoppable) {
+                ((Stoppable) instanceEnabler).stop();
+            }
+        }
+    }
 }

leshan-client-demo/src/main/java/org/eclipse/leshan/client/demo/MyDevice.java

@@ -14,6 +14,7 @@
 
 import org.eclipse.leshan.client.resource.BaseInstanceEnabler;
 import org.eclipse.leshan.client.servers.ServerIdentity;
+import org.eclipse.leshan.core.Destroyable;
 import org.eclipse.leshan.core.model.ObjectModel;
 import org.eclipse.leshan.core.model.ResourceModel.Type;
 import org.eclipse.leshan.core.node.LwM2mResource;
@@ -23,17 +24,19 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class MyDevice extends BaseInstanceEnabler {
+public class MyDevice extends BaseInstanceEnabler implements Destroyable {
 
     private static final Logger LOG = LoggerFactory.getLogger(MyDevice.class);
 
     private static final Random RANDOM = new Random();
     private static final List<Integer> supportedResources = Arrays.asList(0, 1, 2, 3, 9, 10, 11, 13, 14, 15, 16, 17, 18,
             19, 20, 21);
 
+    private final Timer timer;
+
     public MyDevice() {
         // notify new date each 5 second
-        Timer timer = new Timer("Device-Current Time");
+        this.timer = new Timer("Device-Current Time");
         timer.schedule(new TimerTask() {
             @Override
             public void run() {
@@ -210,4 +213,9 @@ private long getMemoryTotal() {
     public List<Integer> getAvailableResourceIds(ObjectModel model) {
         return supportedResources;
     }
+
+    @Override
+    public void destroy() {
+        timer.cancel();
+    }
 }

leshan-client-demo/src/main/java/org/eclipse/leshan/client/demo/RandomTemperatureSensor.java

@@ -11,14 +11,15 @@
 
 import org.eclipse.leshan.client.resource.BaseInstanceEnabler;
 import org.eclipse.leshan.client.servers.ServerIdentity;
+import org.eclipse.leshan.core.Destroyable;
 import org.eclipse.leshan.core.model.ObjectModel;
 import org.eclipse.leshan.core.response.ExecuteResponse;
 import org.eclipse.leshan.core.response.ReadResponse;
 import org.eclipse.leshan.core.util.NamedThreadFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class RandomTemperatureSensor extends BaseInstanceEnabler {
+public class RandomTemperatureSensor extends BaseInstanceEnabler implements Destroyable {
 
     private static final Logger LOG = LoggerFactory.getLogger(RandomTemperatureSensor.class);
 
@@ -113,4 +114,9 @@ private void resetMinMaxMeasuredValues() {
     public List<Integer> getAvailableResourceIds(ObjectModel model) {
         return supportedResources;
     }
+
+    @Override
+    public void destroy() {
+        scheduler.shutdown();
+    }
 }