From ce24c79d8a7100ad9801a580fe91ad6414dfc45b Mon Sep 17 00:00:00 2001
From: Harald Wolff <haraldwolff@homework.praeziso.lupus>
Date: Wed, 8 Jun 2016 23:33:43 +0200
Subject: [PATCH] Scheduler

---
 src/org/hwo/scheduler/Scheduler.java | 106 +++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 src/org/hwo/scheduler/Scheduler.java

diff --git a/src/org/hwo/scheduler/Scheduler.java b/src/org/hwo/scheduler/Scheduler.java
new file mode 100644
index 0000000..afc8940
--- /dev/null
+++ b/src/org/hwo/scheduler/Scheduler.java
@@ -0,0 +1,106 @@
+package org.hwo.scheduler;
+
+import java.util.LinkedList;
+import java.util.List;
+
+public class Scheduler extends Thread{
+
+	private List<SchedulerTask> schedulerTasks;
+	private boolean exit;
+	
+	public Scheduler(){
+		schedulerTasks = new LinkedList<Scheduler.SchedulerTask>();
+		exit = false;
+		
+		
+		start();
+	}
+	
+	public synchronized void schedule(Runnable runnable,int intervall,boolean fixedIntervall){
+		SchedulerTask task = new SchedulerTask(runnable, fixedIntervall, intervall);
+		this.schedulerTasks.add(task);
+		this.notify();
+	}
+	
+	public synchronized void shutdown(){
+		this.exit = true;
+	}
+	
+	
+	@Override
+	public void run() {
+		
+		while (!exit){
+			
+			synchronized (this) {
+				try {
+					this.wait(getWaitTime());
+				} catch (InterruptedException e) {
+				}
+				
+				checkScheduledTasks();
+				
+			}
+			
+			
+		}
+		
+	}
+	
+	private void checkScheduledTasks(){
+		long currentTime = System.currentTimeMillis();
+		
+		for (SchedulerTask task: schedulerTasks){
+			if (task.nextStart <= currentTime){
+				
+				if (task.fixedIntervall)
+					task.nextStart += task.intervall;
+				else
+					task.nextStart = currentTime + task.intervall;
+				
+				try {
+					task.runnable.run();
+				} catch (Exception e){
+					System.err.println("Scheduler caught runnable's Exception!");
+					e.printStackTrace();
+				}
+				
+			}
+		}		
+		
+	}
+	
+	private int getWaitTime(){
+		long currentTime = System.currentTimeMillis();
+		long target = currentTime + 1000;
+		
+		for (SchedulerTask task: schedulerTasks){
+			if (task.nextStart <= target)
+				target = task.nextStart;
+		}
+		int w = (int)(target-currentTime);
+		if (w < 1)
+			return 1;
+		return w;
+	}
+	
+	
+	class SchedulerTask {
+		
+		private int intervall;
+		private Long nextStart;
+		private boolean fixedIntervall;
+		private Runnable runnable;
+		
+		public SchedulerTask(Runnable runnable,boolean fixedIntervall,int intervall) {
+			this.intervall = intervall;
+			this.fixedIntervall = fixedIntervall;
+			this.runnable = runnable;
+			this.nextStart = System.currentTimeMillis() + this.intervall;
+		}
+		
+		
+	}
+}
+
+