Improve TimerSPI to support cancelling of previously scheduled tasks

timer/basic/src/main/java/org/keycloak/timer/basic/BasicTimerProvider.java

@@ -1,5 +1,6 @@
 package org.keycloak.timer.basic;
 
+import org.jboss.logging.Logger;
 import org.keycloak.timer.TimerProvider;
 
 import java.util.Timer;
@@ -10,15 +11,18 @@ import java.util.TimerTask;
  */
 public class BasicTimerProvider implements TimerProvider {
 
-    private Timer timer;
+    private static final Logger logger = Logger.getLogger(BasicTimerProvider.class);
 
-    public BasicTimerProvider(Timer timer) {
+    private final Timer timer;
+    private final BasicTimerProviderFactory factory;
 
+    public BasicTimerProvider(Timer timer, BasicTimerProviderFactory factory) {
         this.timer = timer;
+        this.factory = factory;
     }
 
     @Override
-    public void schedule(final Runnable runnable, final long interval) {
+    public void schedule(final Runnable runnable, final long interval, String taskName) {
         TimerTask task = new TimerTask() {
             @Override
             public void run() {
@@ -26,9 +30,25 @@ public class BasicTimerProvider implements TimerProvider {
             }
         };
 
+        TimerTask existingTask = factory.putTask(taskName, task);
+        if (existingTask != null) {
+            logger.infof("Existing timer task '%s' found. Cancelling it", taskName);
+            existingTask.cancel();
+        }
+
+        logger.infof("Starting task '%s' with interval '%d'", taskName, interval);
         timer.schedule(task, interval, interval);
     }
 
+    @Override
+    public void cancelTask(String taskName) {
+        TimerTask existingTask = factory.removeTask(taskName);
+        if (existingTask != null) {
+            logger.infof("Cancelling task '%s'", taskName);
+            existingTask.cancel();
+        }
+    }
+
     @Override
     public void close() {
         // do nothing

timer/basic/src/main/java/org/keycloak/timer/basic/BasicTimerProviderFactory.java

@@ -6,6 +6,9 @@ import org.keycloak.timer.TimerProvider;
 import org.keycloak.timer.TimerProviderFactory;
 
 import java.util.Timer;
+import java.util.TimerTask;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * @author <a href="mailto:sthorger@redhat.com">Stian Thorgersen</a>
@@ -14,9 +17,11 @@ public class BasicTimerProviderFactory implements TimerProviderFactory {
 
     private Timer timer;
 
+    private ConcurrentMap<String, TimerTask> scheduledTasks = new ConcurrentHashMap<String, TimerTask>();
+
     @Override
     public TimerProvider create(KeycloakSession session) {
-        return new BasicTimerProvider(timer);
+        return new BasicTimerProvider(timer, this);
     }
 
     @Override
@@ -35,4 +40,12 @@ public class BasicTimerProviderFactory implements TimerProviderFactory {
         return "basic";
     }
 
+    protected TimerTask putTask(String taskName, TimerTask task) {
+        return scheduledTasks.put(taskName, task);
+    }
+
+    protected TimerTask removeTask(String taskName) {
+        return scheduledTasks.remove(taskName);
+    }
+
 }