Working head queue thing

Code/P2_Jobs.java

@@ -20,12 +20,7 @@ public class P2_Jobs implements Runnable{
 
     public void run()
     {   
-        int head=0;   
+        printer.requestPrint(this,printer.requestHead());
-        do
-        {
-            //While the job hasn't been started, keep nagging
-            head = printer.requestHead();
-        }while(!printer.requestPrint(this,head));
         
         //Once we're out of that while loop, we're done.        
         done = true;

Code/P2_Printer.java

@@ -1,73 +1,46 @@
+import java.util.LinkedList;
+
 public class P2_Printer{
 
     private int[] time = {0};   //Really hacky solution, but seems easier than wrapping in a custom object.
     private char printerMode = 'M';
 
-    private P2_PrinterHead p1 = new P2_PrinterHead();
+    private LinkedList<P2_PrinterHead> printerHeadsWaiting = new LinkedList<P2_PrinterHead>();
-    private P2_PrinterHead p2 = new P2_PrinterHead();
-    private P2_PrinterHead p3 = new P2_PrinterHead();
 
+    private P2_PrinterHead p1 = new P2_PrinterHead(1);
+    private P2_PrinterHead p2 = new P2_PrinterHead(2);
+    private P2_PrinterHead p3 = new P2_PrinterHead(3);
 
     public P2_Printer() 
     {
         //Nothing to set up.
+        printerHeadsWaiting.add(p1);
+        printerHeadsWaiting.add(p2);
+        printerHeadsWaiting.add(p3);
     }
 
-    public synchronized int requestHead()
+    public synchronized P2_PrinterHead requestHead()
     {
-        int head = 1;
+        while(printerHeadsWaiting.size()==0)
-        int shortestTimeRemaining = p1.getTimeRemaining();
-        
-        if(shortestTimeRemaining > p2.getTimeRemaining())
         {
-            shortestTimeRemaining = p2.getTimeRemaining();
+            //If there isn't a head available, pause for a moment and check again.
-            head = 2;
+            try
+            {
+                Thread.sleep(0);
+            }
+            catch(Exception e)
+            {
+                //Don't caare
+            }
         }
-
+        return printerHeadsWaiting.removeFirst();
-        if(shortestTimeRemaining > p3.getTimeRemaining())
-        {
-            head = 3;
-        }
-
-        return head;
     }
 
-    public boolean requestPrint(P2_Jobs jobInput, int headInput)
+    public boolean requestPrint(P2_Jobs jobInput, P2_PrinterHead printHeadToUse)
     {
-        //Check if job can be done currently
+        printHeadToUse.print(jobInput, time);
-        if(jobInput.getJobType()==printerMode)  //If the job matches the current printer mode
+        printerHeadsWaiting.add(printHeadToUse);
-        {   
+        return true;
-            //If there is an available head
-            if(headInput==1)
-            {
-                //Send to a head to be printed and count the time
-                int startTime = p1.print(jobInput, time);
-                System.out.println("("+startTime+") "+jobInput.getId()+" uses head 1 (time: "+jobInput.getPages()+")");
-                return true;
-            }
-            else if(headInput==2)
-            {
-                int startTime = p2.print(jobInput, time);
-                System.out.println("("+startTime+") "+jobInput.getId()+" uses head 2 (time: "+jobInput.getPages()+")");
-                return true;
-            }
-            else if(headInput==3)
-            {
-                int startTime = p3.print(jobInput, time);
-                System.out.println("("+startTime+") "+jobInput.getId()+" uses head 3 (time: "+jobInput.getPages()+")");
-                return true;
-            }
-            else
-            {
-                return false;
-            }
-        }
-        else
-        {
-            //Keep waiting and asking
-            return false;
-        }
-        
     }
 
 }

Code/P2_PrinterHead.java

@@ -1,22 +1,22 @@
 public class P2_PrinterHead{
 
     private char mode = 'M';
-    private boolean inUse=false;
     private String jobId;
     private int timeRemaining = 0;
 
-    public P2_PrinterHead() 
+    private int id;
+
+    public P2_PrinterHead(int idInput) 
     {
         //Nothing to set up.
+        id = idInput;
     }
 
-    public synchronized int print(P2_Jobs jobInput, int[] time)
+    public synchronized void print(P2_Jobs jobInput, int[] time)
     {
         //Set the details of the current job
         jobId = jobInput.getId();
         mode = jobInput.getJobType();
-        inUse = true;
-        timeRemaining = jobInput.getPages();
         int startTime = time[0];
 
         //Wait (and delay the thread) one second per page of the job
@@ -25,7 +25,6 @@ public class P2_PrinterHead{
             try
             {
                 Thread.sleep(1000);
-                timeRemaining--;
                 time[0]++;
             }
             catch(Exception e)
@@ -33,23 +32,21 @@ public class P2_PrinterHead{
                 //Don't actually care
             }
         }
-
+        System.out.println("("+startTime+") "+jobInput.getId()+" uses head "+getId()+"(time: "+jobInput.getPages()+")");
-        //Head is now available for another activity
-        inUse = false;
-        return startTime;
     }
 
     //Getters
+
+    public int getId()
+    {
+        return id;
+    }
+
     public String getJobId()
     {
         return jobId;
     }
 
-    public boolean getInUse()
-    {
-        return inUse;
-    }
-
     public char getMode()
     {
         return mode;