delete Observer and fixed NoSuchElementException

kieker.live.demo/src/livedemo/managedbeans/ChartBean.java

@@ -10,6 +10,7 @@ import java.util.Observable;
 import java.util.Observer;
 
 import javax.annotation.PostConstruct;
+import javax.annotation.PreDestroy;
 import javax.faces.bean.ManagedBean;
 import javax.faces.bean.ManagedProperty;
 import javax.faces.bean.SessionScoped;
@@ -74,6 +75,11 @@ public class ChartBean implements Observer{
 		}
 	}
 	
+	@PreDestroy
+	public void cleanup(){
+		this.dataBean.deleteObserver(this);
+	}
+	
 	public void setDataBean(DataBean dataBean){
 		this.dataBean = dataBean;
 	}

kieker.live.demo/src/livedemo/managedbeans/CpuBean.java

@@ -12,6 +12,7 @@ import java.util.Observer;
 import java.util.Set;
 
 import javax.annotation.PostConstruct;
+import javax.annotation.PreDestroy;
 import javax.faces.bean.ManagedBean;
 import javax.faces.bean.ManagedProperty;
 import javax.faces.bean.SessionScoped;
@@ -89,6 +90,11 @@ public class CpuBean implements Observer{
 		}
 	}
 	
+	@PreDestroy
+	public void cleanup(){
+		this.dataBean.deleteObserver(this);
+	}
+	
 	// getter and setter
 	public void setDataBean(DataBean dataBean){
 		this.dataBean = dataBean;

kieker.live.demo/src/livedemo/managedbeans/DataBean.java

@@ -145,12 +145,11 @@ public class DataBean extends Observable{
 		}
 		
 		// remove old records
-		if(!this.records.isEmpty()){
 		long currentTime = System.currentTimeMillis() * 1000000;
-			while((currentTime - this.recordStorageDuration) > this.records.getFirst().getOperationExecutionRecord().getLoggingTimestamp()){
+		while(!this.records.isEmpty() && 
+				(currentTime - this.recordStorageDuration) > this.records.getFirst().getOperationExecutionRecord().getLoggingTimestamp()){
 			this.records.removeFirst();
 		}
-		}
 		
 		this.setChanged();
 		this.notifyObservers("oer");