allows to start-stop-start-stop-... a reconnect strategy (#4168)

* allows to start-stop-start-stop-... a reconnect strategy A MQTT Broker Connection must be able to handle start and stop iterations. Related to: #3980 (comment) Signed-off-by: Markus Rathgeb <maggu2810@gmail.com>
eclipse-archived · Sep 1, 2017 · 0f334f0 · 0f334f0
1 parent 484cc84
commit 0f334f0
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Showing 3 changed files with 55 additions and 25 deletions.
diff --git a/...port.mqtt/src/main/java/org/eclipse/smarthome/io/transport/mqtt/MqttBrokerConnection.java b/...port.mqtt/src/main/java/org/eclipse/smarthome/io/transport/mqtt/MqttBrokerConnection.java
@@ -548,6 +548,11 @@ public synchronized void start() throws MqttException, ConfigurationException {
             return;
         }
 
+        // Ensure the reconnect strategy is started
+        if (reconnectStrategy != null) {
+            reconnectStrategy.start();
+        }
+
         if (StringUtils.isBlank(clientId) || clientId.length() > 23) {
             clientId = MqttClient.generateClientId();
         }
@@ -579,15 +584,18 @@ public synchronized void start() throws MqttException, ConfigurationException {
 
     /**
      * Close the MQTT connection.
+     *
+     * You can re-establish a connection calling {@link #start()} again.
      */
     public synchronized void close() {
         logger.trace("Closing the MQTT broker connection '{}'", getName());
 
         // Abort a connection attempt
         isConnecting = false;
 
+        // Stop the reconnect strategy
         if (reconnectStrategy != null) {
-            reconnectStrategy.close();
+            reconnectStrategy.stop();
         }
 
         // Close connection

diff --git a/...ain/java/org/eclipse/smarthome/io/transport/mqtt/reconnect/AbstractReconnectStrategy.java b/...ain/java/org/eclipse/smarthome/io/transport/mqtt/reconnect/AbstractReconnectStrategy.java
@@ -7,8 +7,6 @@
  */
 package org.eclipse.smarthome.io.transport.mqtt.reconnect;
 
-import java.io.Closeable;
-
 import org.eclipse.smarthome.io.transport.mqtt.MqttBrokerConnection;
 import org.eclipse.smarthome.io.transport.mqtt.MqttConnectionObserver;
 
@@ -18,7 +16,7 @@
  *
  * @author David Graeff - Initial contribution
  */
-public abstract class AbstractReconnectStrategy implements Closeable {
+public abstract class AbstractReconnectStrategy {
     protected MqttBrokerConnection brokerConnection;
 
     /**
@@ -56,8 +54,16 @@ public MqttBrokerConnection getBrokerConnection() {
     public abstract void connectionEstablished();
 
     /**
-     * This will be called if your reconnect strategy should no longer try to handle a reconnect.
+     * Start the reconnect strategy handling.
+     */
+    public abstract void start();
+
+    /**
+     * Stop the reconnect strategy handling.
+     *
+     * <p>
+     * It must be possible to restart a reconnect strategy again after it has been stopped.
      */
-    @Override
-    public abstract void close();
+    public abstract void stop();
+
 }
diff --git a/...ain/java/org/eclipse/smarthome/io/transport/mqtt/reconnect/PeriodicReconnectStrategy.java b/...ain/java/org/eclipse/smarthome/io/transport/mqtt/reconnect/PeriodicReconnectStrategy.java
@@ -30,9 +30,8 @@ public class PeriodicReconnectStrategy extends AbstractReconnectStrategy {
     private final int reconnectFrequency;
     private final int firstReconnectAfter;
 
-    private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
+    private ScheduledExecutorService scheduler = null;
     private ScheduledFuture<?> scheduledTask;
-    boolean closed = false;
 
     /**
      * Use a default 60s reconnect frequency and try the first reconnect after 10s.
@@ -54,10 +53,40 @@ public PeriodicReconnectStrategy(int reconnectFrequency, int firstReconnectAfter
         this.firstReconnectAfter = firstReconnectAfter;
     }
 
+    @Override
+    public synchronized void start() {
+        if (scheduler == null) {
+            scheduler = Executors.newScheduledThreadPool(1);
+        }
+    }
+
+    @Override
+    public synchronized void stop() {
+        if (scheduler != null) {
+            scheduler.shutdownNow();
+            scheduler = null;
+        }
+
+        // If there is a scheduled task ensure it is canceled.
+        if (scheduledTask != null) {
+            scheduledTask.cancel(true);
+            scheduledTask = null;
+        }
+    }
+
+    /**
+     * Returns if the reconnect strategy has been started.
+     *
+     * @return true if started
+     */
+    public synchronized boolean isStarted() {
+        return scheduler != null;
+    }
+
     @Override
     public synchronized void lostConnection() {
-        // If we has been already closed, there is nothing to do.
-        if (closed) {
+        // Check if we are running (has been started and not stopped) state.
+        if (scheduler == null) {
             return;
         }
 
@@ -80,6 +109,7 @@ public synchronized void lostConnection() {
 
     @Override
     public synchronized void connectionEstablished() {
+        // Stop the reconnect task if existing.
         if (scheduledTask != null) {
             scheduledTask.cancel(true);
             scheduledTask = null;
@@ -98,18 +128,4 @@ public int getReconnectFrequency() {
     public int getFirstReconnectAfter() {
         return firstReconnectAfter;
     }
-
-    @Override
-    public synchronized void close() {
-        closed = true;
-
-        // Shutdown the scheduler.
-        scheduler.shutdownNow();
-
-        // If there is a scheduled task ensure it is canceled.
-        if (scheduledTask != null) {
-            scheduledTask.cancel(true);
-            scheduledTask = null;
-        }
-    }
 }