How do I start optimising my Java code? - CPU is a

Question

i have written an application, but for some reason it keeps peaking at 100%. I ran a profile r on a few of the classes and a report show that isReset() and isRunning() seems to be called alot of times. Do you see anything wrong please inform me. thanks

Class 1 is the only class that uses the isReset() code so i hope this helps u guys in detecting the error

Class 1

package SKA;
/*
 * ver 0.32 June 2009
 * 
 * Bug Fix Release:
 * 
 * Fixed Array resize
 * Fixed Red Black Tree delete method 
 * Fixed Red Black Tree save/read option
 * Update help file
 * 
 */





/*
 * Additions:
 * ver 0.30 May 2009
 * 
 * Added Red Black Tree structure
 * Added Delete method for canvases
 * Added Array structure
 * Added ability to recolor nodes.
 * Added Bubble Sort Algorithm
 * Added Insertion Sort Algorithm
 * Added Shell Sort Algorithm
 * Added Selection Sort Algorithm
 * Added Quick Sort Algorithm
 * Added Red Black Tree Search Algorithm
 * Added Black Height Check Algorithm
 * Bug fix in canvas - could not delete canvas properly
 */

// Additions: 
/* ver 0.25 August 2004
 *  Added recursion in SkaExecutionPanel by adding SkaFunction 
 *      and using desktop internal panes.
 *
 *  Added binary tree node annotation - text and drawn
 *  Added subtree highlight feature to VizBinaryTreeNode using SkaRectangle
 *  Improved node highlighting and selection scheme in VizBinaryTrees/VizDS
 *  Added Binary tree save and read methods
 *  Added visual subtree deletion (has bug)
 *
 *  Added ability to set breaks from within algorithm
 *  Added tooltip messages to SkaProgram/SkaFunction to show variable values
 *  Added simple value input and output methods to SkaProgram/SkaFunction 
 *  Added SkaTriangle.
 *  Added Font Adjustment and Color scheme options to show on overhead projectors
 *  
 *  Found bug in SkaGraph deleteVertex (with edges)
 */

/* ver 0.16 October 15, 2001
  Added Graph save and read methods.
  Save is an instance method, while read is a class method.

  Added circular layout for graphs, 
  Added fit/adjust graph layout to plate size method.

  Added label editing for Binary Trees and Graphs. 
  SkaLabels (glyphs) now truncate the string displayed to the width specified 
  in the constructor.

*/

/* ver 0.15 July 21, 2001
   Fixed Reset function in Execution using exceptions so that Ska Algorithms 
   can be run repeatedly without quitting the entire Ska System.
   This also allows trying the same program on different data structures.

   Problems with reset so far:
   1. Reset message to user can appear much later.
      I think this is an I/O sequencing problem and it should go away if 
      a message status GUI area is used.

   2. Bound variable names remain afterwards, 
      e.g. Graph bound to G will still show name as G after
      algorithm is interrupted.      

   Fixed problem with multiple input requests in 0.14 - by adding another
      wait call which waits on before asking for input.

   Also introduced trial orderly layout of canvas and program windows ,
   which fixes problem in 0.14  
*/

 /* ver 0.14 July 18, 2001

   Added subclasses of SkaProgram, so that multiple programs
   can run simultaneously. 
   Problem - when multiple programs start, their windows overlay each other
   Problem - Send DS to algorithm can get confused, if an algorithm 
      requests input while another is waiting on input or if 
      two algorithms request input at the same time
*/

/* ver 0.13   

   Added BinaryTree - does not have node value display yet.
   Added arrows on edges of directed graphs
*/   

/* ver 0.12

      Added VizElementListener - separated from VizElement
      Element Input menu item only highlights when input for that DS is requested
      DS Input has been cleaned up
*/

/* ver 0.11

    can ask user to select individual elements, e.g. vertices
    removed standard java cloning code which wasn't being used anyway
*/


import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.KeyStroke;
import javax.swing.border.BevelBorder;
import javax.swing.border.SoftBevelBorder;


// TimerQueue

public class SkaTest {
   public static final int WIDTH = 500;
   public static final int HEIGHT = 500;
   public static final int CANVAS_X = 100;
   public static final int CANVAS_Y = 100;
   public static final int CANVAS_FRAME_WIDTH = WIDTH+100;
   public static final int CANVAS_FRAME_HEIGHT = HEIGHT + 100;
   public static final int EXEC_WIDTH = 550;
   public static final int EXEC_HEIGHT = 400;

   static VizDSList dsList = new VizDSList();
   static SkaCanvas canvas = new SkaCanvas(dsList);
   static JFrame canvasFrame = new JFrame("Data Structure Canvas");
   static JMenuBar menuBar = new JMenuBar();
   static JMenu algorithmMenu = new JMenu("Algorithm");
   static JMenu dsMenu = new JMenu("Create");
   static JMenu helpMenu = new JMenu ("Help");
   static JLabel status = new JLabel(" ");   

   static SkaProgram[] alg;
   static JFrame execFrame[];
   static SkaExecutionPanel execPanel[];


   public static void setupFrames(int nAlgs) {
      int i; 

      for (i=0; i < nAlgs; i++) {
         // execFrame[i] = new JFrame("Execution Control Panel "+(i+1));
         execFrame[i] = new JFrame();
         execPanel[i] = new SkaExecutionPanel(execFrame[i]);
      }

      canvas.setMinimumSize(new Dimension(WIDTH, HEIGHT));
      canvasFrame.setSize(CANVAS_FRAME_WIDTH, CANVAS_FRAME_WIDTH);
      canvasFrame.getContentPane().setLayout(new BorderLayout(10,7));
      // canvasFrame.getContentPane().setPreferredSize(new Dimension(WIDTH, HEIGHT));
      canvasFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
            System.exit(0);
         }
      });
      // canvas.setMinimumSize(new Dimension(WIDTH, HEIGHT));

      for (i=0; i < nAlgs; i++) {
         execFrame[i].setSize(EXEC_WIDTH, EXEC_HEIGHT);
         // execFrame[i].getContentPane().setLayout(new BorderLayout(10,7));
         execFrame[i].addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
               System.exit(0);
            }
         });
         execPanel[i].setBorder(new SoftBevelBorder(BevelBorder.RAISED));
         // execFrame[i].setContentPane(execPanel[i]);
         execFrame[i].getContentPane().add("Center", execPanel[i]);
         // execFrame[i].setLocation(CANVAS_X +CANVAS_FRAME_WIDTH, CANVAS_Y + i*EXEC_HEIGHT);
         execFrame[i].setLocation(CANVAS_X +CANVAS_FRAME_WIDTH + i*30, CANVAS_Y + i*50);
      }

      canvas.setBorder(new SoftBevelBorder(BevelBorder.RAISED));
      canvasFrame.getContentPane().add("Center", new JScrollPane(canvas) );
      // canvasFrame.getContentPane().add("Center", new JScrollPane(canvas, ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS) );
      canvasFrame.getContentPane().add("South", status);
      canvasFrame.setLocation(CANVAS_X, CANVAS_Y);

      JMenu fileMenu = new JMenu("File");
      JMenuItem quitItem = new JMenuItem("Quit");
      //TODO Add quit listener
      quitItem.addActionListener(new ActionListener ()
      {


        public void actionPerformed(ActionEvent arg0) {
            //System.exit(0);

            int again = JOptionPane.showConfirmDialog(null, "Are you sure you want to exit system", "Exiting", JOptionPane.YES_NO_OPTION);
            if (again == JOptionPane.YES_OPTION)
            {
                System.exit(0);
            }


        }

      }
      );
      fileMenu.add(quitItem);
      menuBar.add(fileMenu);
      menuBar.add(algorithmMenu);
     // menuBar.add(dsMenu);
      menuBar.add(helpMenu);
      JMenuItem help = new JMenuItem ("Help Contents");
      //help.setMnemonic(KeyEvent.VK_H);
      //TODO Fix this method
      help.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_F1, ActionEvent.CTRL_MASK));
      help.addActionListener(new ActionListener()
      {
/*
        @Override
        public void actionPerformed(ActionEvent arg0) {
            JOptionPane.showMessageDialog(null, "Alot of the functionality have not yet been included in this version\nCurrently working on the automation features now!", "SKA 0.2 Beta", JOptionPane.WARNING_MESSAGE);

        }
*/

        public void actionPerformed(ActionEvent arg0) {
            try {
                Runtime.getRuntime().exec("hh.exe C:/ska.chm");
            } catch (IOException e) {
                e.printStackTrace();
                JOptionPane.showMessageDialog(null, "File not found", "Error", JOptionPane.ERROR_MESSAGE);
            }


        }

      });
      JMenuItem about = new JMenuItem ("About SKA");
      about.addActionListener(new ActionListener(){


        public void actionPerformed(ActionEvent arg0) {
        JOptionPane.showMessageDialog(null, "SKA Version 0.1 Beta");

        }
    });
      helpMenu.add(help);
      helpMenu.add(about);
      canvasFrame.setJMenuBar(menuBar);
   }

   /** The create menu item  */
   public static void createProgram(int i) {
      JMenuItem algItem;
      switch (i) {
      case 0 :
          alg[0] = new RedBlackValidate(canvas, execPanel[0]);
          execFrame[0].setTitle("Validate Algorithm");
          System.out.println("Validate Algorithm");
          algItem = new JMenuItem("Validate Algorithm");
          algorithmMenu.add(algItem);
          break;
   /*   case 0 :
         alg[0] = new BreadthFirstSearch(canvas, execPanel[0]);
         execFrame[0].setTitle("BFS Graph Algorithm");
         // System.out.println("BreadthFirstSearch");
         algItem = new JMenuItem("BFS Graph Algorithm");
         algorithmMenu.add(algItem);
         break;
      case 1:
         alg[1] = new LevelOrderAlgorithm(canvas, execPanel[1]);
         execFrame[1].setTitle("Level Order Tree Algorithm");
         System.out.println("LevelOrderAlgorithm");
         algItem = new JMenuItem("Level Order Tree Algorithm");
         algorithmMenu.add(algItem);
         break;         
      case 2:
         alg[2] = new BinarySearchTreeAlgRecursive(canvas, execPanel[2]);
         execFrame[2].setTitle("BinaryTreeSearchRec Algorithm");
         System.out.println("BinaryTreeSearchRec Algorithm");
         algItem = new JMenuItem("BinaryTreeSearchRec Algorithm");
         algorithmMenu.add(algItem);
         break;         
      case 3:
         alg[3] = new BinarySearchTreeAlgIterative(canvas, execPanel[3]);
         execFrame[3].setTitle("BinaryTreeSearchIter Algorithm");
         System.out.println("BinaryTreeSearchIter Algorithm");
         algItem = new JMenuItem("BinaryTreeSearchIter Algorithm");
         algorithmMenu.add(algItem);
         break;         
      case 4:
          alg[4] = new RebBlackTreeSearch (canvas, execPanel[4]);
          execFrame[4].setTitle("Red Black Search Algorithm");
          System.out.println("Red Black Search Algorithm");
          algItem = new JMenuItem("Red Black Search Algoithm Algorithm");
          algorithmMenu.add(algItem);
          break;
      case 5:
          alg[5] = new ArrayInsertionSortAlg (canvas, execPanel[5]);
          execFrame[5].setTitle("Array Insertion Sort Algorithm");
          System.out.println("Array Insertion Sort");
          algItem = new JMenuItem("Array Insertion Sort Algorithm");
          algorithmMenu.add(algItem);
          break;
      case 6:
          alg[6] = new ArraySelectionSortAlg (canvas, execPanel[6]);
          execFrame[6].setTitle("Array Selection Sort Algorithm");
          System.out.println("Array SelectionSearch");
          algItem = new JMenuItem("Array Selection Sort Algorithm");
          algorithmMenu.add(algItem);
          break; */
      default:
         break;         
      }
   }


   public static void main(String args[]) {
      int i, nAlgs = 1; //nAlgs = 7;

      alg = new SkaProgram[nAlgs];
      execPanel = new SkaExecutionPanel[nAlgs];
      execFrame = new JFrame[nAlgs];

      // canvas.setDebugGraphicsOptions(DebugGraphics.BUFFERED_OPTION);
      setupFrames(nAlgs);
      canvasFrame.setVisible(true);


      for (i=0; i < alg.length; i++) {
         createProgram(i);
         execFrame[i].setVisible(true);
         alg[i].start();
         alg[i].displayAlgorithm();
      }

      while (true) {
         for (i=0; i < alg.length; i++) 
            if (execPanel[i].isReset()) {
               alg[i].terminate();
               createProgram(i);
               alg[i].start();
               execPanel[i].unreset();
            }         
      }
   }
}  // End class SkaTest

Class 2

package SKA;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.Stack;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JComboBox;
import javax.swing.JDesktopPane;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JToolBar;

@SuppressWarnings("serial")
public

class SkaExecutionPanel extends JDesktopPane {

   public static final int EXEC_WIDTH = SkaTest.EXEC_WIDTH-100;
   public static final int EXEC_HEIGHT = SkaTest.EXEC_HEIGHT-50;

   boolean run = false, pause = true, step = false, reset = false;
   JToolBar toolbar = new JToolBar();
   JTextArea textOutputArea = new JTextArea();

   SkaProgram prog;
   Stack<SkaFunction> functionStack = new Stack<SkaFunction>();

   SkaFunction currentFunction = null;

   int level = 0, in = 30;

   public void doCall(String[] subAlg, String subAlgName) {
      doCall(subAlg, subAlgName, false);   // make non-icon default
   }

   public void doCall(String[] subAlg, String subAlgName, boolean iconify) {      
      if (currentFunction != null)
         functionStack.push(currentFunction);
      currentFunction = new SkaFunction(this, subAlg, subAlgName, iconify);
      add(currentFunction, new Integer(1));
      currentFunction.setBounds(level*in,level*in,EXEC_WIDTH, EXEC_HEIGHT);
      // currentFunction.setBounds(level*in,level*in,EXEC_WIDTH-(level+1)*in, EXEC_HEIGHT-(level+1)*in);
      currentFunction.setVisible(true);
      level++;    
   }


   public void doReturn() {
      if (currentFunction == null)
         return;
      if (currentFunction.makeIconWhenDone()) {
         getDesktopManager().iconifyFrame(currentFunction);        
         // currentFunction.setIcon(true);
         currentFunction.setIconifiable(true);
      }
      else
         currentFunction.setVisible(false);
      currentFunction = (SkaFunction) functionStack.pop();        
      level--;
   }


   public void displayAlgorithm(String[] a) {
      doCall(a, "main");
   }

   public void displayAlgorithm(String[] a, String aname) {
      doCall(a, aname);
   }

   public void setControlsEnabled(boolean b) {
      toolbar.setEnabled(b);
   }


   class RunAction extends AbstractAction {
      RunAction() {
         super("run");
      }

      public void actionPerformed(ActionEvent e) {
         run = true; pause = false; step = false;      
      }
   }


   class StepAction extends AbstractAction {
      StepAction() {
         super("step");
      }

      public void actionPerformed(ActionEvent e) {
         run = false; pause = false; step = true;      
      }
   }


   class PauseAction extends AbstractAction {
      PauseAction() {
         super("pause");
      }

      public void actionPerformed(ActionEvent e) {
         pause = true; 
         //         System.out.print("breaks");
         //         for (int i=0; i<breaks.length; i++)
         //            System.out.print("[" +i+ "]=" + breaks[i].toString() + "  ");
         //         System.out.println("");   

      }
   }


   class ResetAction extends AbstractAction {
      ResetAction() {
         super("reset");
         putValue(Action.SHORT_DESCRIPTION, "stop program and reset state to begining");
      }

      public void actionPerformed(ActionEvent e) {
         run = false; pause = true; step = false;      
         // should also restart SkaProgram
         reset = true;

         if (currentFunction != null) currentFunction.reset();
         /*
         JInternalFrame[] frames = getAllFrames();
         for (int i = 0; i < frames.length; i++) {
         // frames[i].dispose();
         if (frames[i].isIcon())
         frames[i].dispose();
         } 
         */
      }
   }


   JComboBox speedControl;
   String speedNames[] =  { "slow", "normal", "fast", "very fast" };
   int speeds[] =  {4000, 2000, 1000, 500} ; // milliseconds
   int speed = speeds[1];
   private void initSpeedMenu() {
      speedControl = new JComboBox(speedNames);
      // speedControl.setMaximumRowCount(3);
      speedControl.addItemListener(
         new ItemListener() {
         public void itemStateChanged( ItemEvent e) {
            speed = speeds[speedControl.getSelectedIndex()];
         }
      }
      );
      speedControl.setSelectedIndex(1);
      speedControl.setMaximumSize(speedControl.getPreferredSize());
      speedControl.setToolTipText("execution speed");
   }


   SkaExecutionPanel(JFrame frame) {
      initSpeedMenu();
      toolbar.add(new RunAction());
      toolbar.add(new StepAction());
      toolbar.add(new ResetAction());
      toolbar.add(new PauseAction());
      toolbar.addSeparator();
      toolbar.add(speedControl);

      // frame.getContentPane().setLayout(new BorderLayout(10,7));

      // makeTable();

      frame.getContentPane().add("North", toolbar);  

      Font f = new Font("SansSerif", Font.BOLD, 14);
      textOutputArea.setFont(f);

      frame.getContentPane().add("South", new JScrollPane(textOutputArea));
      // frame.getContentPane().add(this, BorderLayout.CENTER)
      // frame.getContentPane().add("Center", toolbar, BorderLayout.NORTH);  
      // setSize(300,250);    

      // add toolbar, table, set layout, sizes         
   }


   //   public void setAlgorithm(SkaProgram p)  {
   //      prog = p;
   //      sendAlgorithm(p.getPseudocode());
   //   }


   public int getSpeed() { return speed; 
   }

   public boolean isRunning() { return run; 
   }
   public boolean isPaused() { return pause; 
   }
   public boolean isStepping() { return step; 
   }
   public boolean isReset() { return reset; 
   }

   public void pause() { pause = true; 
   }
   public void unreset() { reset = false; 
   }

   public void aboutToWait() {
      currentFunction.aboutToWait();
   }

   public void doneWait() {
      currentFunction.doneWait();
   }

   public void showToolTipValue(String s)  {
      currentFunction.showToolTipValue(s);
   }

   public void showAlgLineBreak(int i) {
      currentFunction.showAlgLineBreak(i);
   }      

   public void showAlgLine(int i) {
      currentFunction.showAlgLine(i);
   }      


   public void displayText(String s) {
      textOutputArea.append(s);  // +"\n"   add newline?
   }

} // End class SkaExecutionPanel

Answer 1

Start with the most intensively used method in your readout and move to less and less intense methods until you find one with a loop construct (for, while). Check the loop construct to see if it is doing too much work, and see if the functions that call this function call it often.

i.e (pseudocode)

dotProduct(vector a, vector b)
{
  //create vector dot product here
  maths maths maths
}

calc(data)
{
  for obj in data:
    dotproduct(obj, foo)
}

dotProduct will use the most CPU time, but calc is the place to start - can we cache results? are we recalculating data? Are we iterating through data in a stupid way?

Answer 2

Judging by the function names "isReset()" and "isRunning()" being called a lot, I would guess that you're wasting CPU time polling for a condition/event. Java should have some sort of semaphore/signalling system that you can use to let the do-er notify the wait-er exactly when the event occurs.

Answer 3

"How do I start optimising my Java code?"

You start by profiling it first.

Answer 4

The problem doesn't seem to be in the methods which are being used a lot, it's how frequently you call them which appears to be why they are showing up so frequently. I'd check for all of the calls, see if any are superfluous then go to the third most time consuming method. After that, I would check my algorithms for being particularly intensive. Also, check all method calls and make sure they're not being run without need.

I know this isn't solving the problem itself, but its a start with the information given.

EDIT: The while loop is an infinite loop causing a for loop to run in which every item in an array has been checked to see if its been reset. You can replace this with an observer pattern where when an object is reset, it notifies the observing object which then performs that set of steps. This way you don't have an infinite loop and you cut down on the usage of .isReset(). This is in the main method of Class 1.

Edit 2: Here's the example of an implementation of the observer pattern which is on wikipedia.

Answer 5

First things first. you have a warning in you code somewhere, as that you have used the annotation

@SuppressWarnings("serial")

. While this very well may have nothing to with your cpu maxing out. Fix this first and you very well may stumble on the problem.