Sanity checks in the PeriodicOperation

- isStopped is true, if the OP is not yet started

src/de/tudarmstadt/maki/simonstrator/api/operation/PeriodicOperation.java

@@ -32,7 +32,7 @@ import de.tudarmstadt.maki.simonstrator.api.util.Distribution;
 public abstract class PeriodicOperation<T extends HostComponent, R> extends
 		AbstractOperation<T, R> {
 
-	private boolean stopped = false;
+	private boolean stopped = true;
 
 	private Distribution intervalDist;
 
@@ -157,6 +157,10 @@ public abstract class PeriodicOperation<T extends HostComponent, R> extends
 	 * Same functionality like scheduleImmediately
 	 */
 	public void start() {
+		if (!isStopped()) {
+			throw new AssertionError(
+					"Periodic Operation already running - ignoring start()!");
+		}
 		this.scheduleImmediately();
 	}
 
@@ -167,6 +171,10 @@ public abstract class PeriodicOperation<T extends HostComponent, R> extends
 	 *            The delay for the first execution
 	 */
 	public void startWithDelay(long delay) {
+		if (!isStopped()) {
+			throw new AssertionError(
+					"Periodic Operation already running - ignoring start()!");
+		}
 		this.scheduleWithDelay(delay);
 	}
 
@@ -176,12 +184,12 @@ public abstract class PeriodicOperation<T extends HostComponent, R> extends
 		super.scheduleWithDelay(delay);
 	}
 
-	@Override
-	public void scheduleImmediately() {
-		this.stopped = false;
-		super.scheduleImmediately();
-	}
-
+	/**
+	 * True, if the operation is currently stopped or was not yet scheduled to
+	 * start.
+	 * 
+	 * @return
+	 */
 	public boolean isStopped() {
 		return stopped;
 	}