Noel Java Blog

Friday, May 18, 2012

Performance test of find cell

public void testFindCell_ICell() throws OutOfBoundsException {
System.out.println("findCell");
int testSize = 1000000;
UniqueRandomNumber urn = new UniqueRandomNumber(testSize);

ArrayListCellColl instance = new ArrayListCellColl();
AliveCell ac;

while (urn.hasNext()){
ac = new AliveCell();
int x = urn.getNext();

ac.setX(x);
ac.setY(x);
instance.addCell(ac);
}
TimerClass timer = new TimerClass();
timer.startTimer();
int counter = 0;
for (int i = 0; i<testSize;i++){
Random gen = new Random();
int z = gen.nextInt(testSize*2);
ac = new AliveCell();
ac.setX(z);
ac.setY(z);
if (instance.findCell(ac))counter++;

}
System.out.println("number found = " + counter);
timer.stopTimer();
System.out.println(timer.duration());

}

Saturday, April 28, 2012

Unique Random Number Generator

package utilities;

import java.util.ArrayList;
import java.util.Collections;

/**
*
* @author noel
*/
public class UniqueRandomNumber {

public static class OutOfBoundsException extends Exception {

public OutOfBoundsException() {
super("Generator past bounds");
}
}
private int size;
private int counter = 0;

private boolean hasNext = false;
private ArrayList <Integer> listOfValues = new ArrayList<Integer>();
public UniqueRandomNumber(int size){
this.size = size;
if (size > 0 ) hasNext = true;
for (int i = 0; i < size; i++){
listOfValues.add(i);
}
Collections.shuffle(listOfValues);

}
public int getNext() throws OutOfBoundsException{
if (counter >= size) throw new OutOfBoundsException();
int returnVal = listOfValues.get(counter);
counter++;
if (counter >= size) hasNext = false;
return returnVal;

}

/**
* @return the hasNext
*/
public boolean hasNext() {
return hasNext;
}

}

Wednesday, April 25, 2012

Timer Class for Performance Testing

package gameoflifeiversion;

/**
*
* @author noel
*/
public class TimerClass {
private long startTime;
private long currentTime;
private long endTime;

public TimerClass(){

}
public void startTimer(){
startTime = System.currentTimeMillis();
}
public String lapTime(){
currentTime = System.currentTimeMillis();
return (currentTime - startTime) + " milliseconds";

}
public void stopTimer(){
endTime = System.currentTimeMillis();
}
public String duration(){

return (endTime - startTime) + " milliseconds";

}
}

More Game of life code

package gameoflifeiversion;

import java.util.Collection;

/**
*
* @author noel
*/
public interface ICellColl {
public ICell findCell(int x, int y);
public ICell findCell (ICell cell);
public Collection<ICell> getNeighbours(ICell cellToFind);
public Collection<ICell> getNeighbours(int x, int y);
public void addCell(ICell cell);

public static class Extent{
private int leastx = 1;
private int greatestx = 1;
private int leasty = 1;
private int greatesty = 1;

/**
* @return the leastx
*/
public int getLeastx() {
return leastx;
}

/**
* @param leastx the leastx to set
*/
public void setLeastx(int in) {
leastx = in;
}

/**
* @return the greatestx
*/
public int getGreatestx() {
return greatestx;
}

/**
* @param greatestx the greatestx to set
*/
public void setGreatestx(int in) {
greatestx = in;
}

/**
* @return the leasty
*/
public int getLeasty() {
return leasty;
}

/**
* @param leasty the leasty to set
*/
public void setLeasty(int in) {
leasty = in;
}

/**
* @return the greatesty
*/
public int getGreatesty() {
return greatesty;
}

/**
* @param greatesty the greatesty to set
*/
public void setGreatesty(int in) {
greatesty = in;
}
}
}

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package gameoflifeiversion;

/**
*
* @author noel
*/
public abstract class AbstractICellColl implements ICellColl {

public AbstractICellColl() {
}
private ICellColl.Extent extent = new ICellColl.Extent();
@Override
public void addCell(ICell cell){

if (cell.getX() < extent.getLeastx()) {
extent.setLeastx(cell.getX());
}
if (cell.getX() > extent.getGreatestx()) {
extent.setGreatestx(cell.getX());
}
if (cell.getY() < extent.getLeasty()) {
extent.setLeasty(cell.getY());
}
if (cell.getY() > extent.getGreatesty()) {
extent.setGreatesty(cell.getY());
}
}

/**
* @return the extent
*/
public ICellColl.Extent getExtent() {
return extent;
}

}

package gameoflifeiversion;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Collections;

/**

* @author noel

public class ArrayListCellColl extends AbstractICellColl{

private ArrayList<ICell> coll = new ArrayList<ICell>();

private boolean hasNewCell = false;

@Override

public ICell findCell(int x, int y) {

AliveCell ac = new AliveCell();

ac.setX(x);

ac.setY(y);

return findCell(ac);

}

@Override

public ICell findCell(ICell cell) {

if (hasNewCell){

Collections.sort(coll);

hasNewCell = false;

}

if (cell == null) return null;

int index = Collections.binarySearch(this.coll, cell);

if (index < 0 )return null;

return coll.get(index);

}

@Override

public Collection<ICell> getNeighbours(ICell cellToFind) {

ArrayList<ICell> neighbours = new ArrayList<ICell>();

ICell addCell = findCell(cellToFind.getX() - 1, cellToFind.getY() - 1);

if (addCell != null) {

neighbours.add(addCell);

}

addCell = findCell(cellToFind.getX(), cellToFind.getY() - 1);

if (addCell != null) {

neighbours.add(addCell);

}

addCell = findCell(cellToFind.getX() + 1, cellToFind.getY() - 1);

if (addCell != null) {

neighbours.add(addCell);

}

addCell = findCell(cellToFind.getX() - 1, cellToFind.getY());

if (addCell != null) {

neighbours.add(addCell);

}

addCell = findCell(cellToFind.getX() + 1, cellToFind.getY());

if (addCell != null) {

neighbours.add(addCell);

}

addCell = findCell(cellToFind.getX() - 1, cellToFind.getY() +1);

if (addCell != null) {

neighbours.add(addCell);

}

addCell = findCell(cellToFind.getX(), cellToFind.getY() +1);

if (addCell != null) {

neighbours.add(addCell);

}

addCell = findCell(cellToFind.getX() + 1, cellToFind.getY() +1);

if (addCell != null) {

neighbours.add(addCell);

}

return neighbours;

}

@Override

public Collection<ICell> getNeighbours(int x, int y) {

AliveCell ac = new AliveCell();

ac.setX(x);

ac.setY(y);

return getNeighbours(ac);

}

@Override

public void addCell(ICell cell) {

hasNewCell = true;

coll.add(cell);

super.addCell(cell);

}

}

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package gameoflifeiversion;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;

/**
*
* @author noel
*/
public class HashMapCellColl extends AbstractICellColl {
private HashMap<ICell, ICell> coll = new HashMap<ICell,ICell>();

@Override
public ICell findCell(int x, int y) {
AliveCell ac = new AliveCell();
ac.setX(x);
ac.setY(y);
return findCell(ac);
}

@Override
public ICell findCell(ICell cell) {
return coll.get(cell);
}

@Override
public Collection<ICell> getNeighbours(ICell cellToFind) {
ArrayList<ICell> neighbours = new ArrayList<ICell>();
ICell addCell = findCell(cellToFind.getX() - 1, cellToFind.getY() - 1);
if (addCell != null) {
neighbours.add(addCell);
}
addCell = findCell(cellToFind.getX(), cellToFind.getY() - 1);
if (addCell != null) {
neighbours.add(addCell);
}
addCell = findCell(cellToFind.getX() + 1, cellToFind.getY() - 1);
if (addCell != null) {
neighbours.add(addCell);
}
addCell = findCell(cellToFind.getX() - 1, cellToFind.getY());
if (addCell != null) {
neighbours.add(addCell);
}
addCell = findCell(cellToFind.getX() + 1, cellToFind.getY());
if (addCell != null) {
neighbours.add(addCell);
}
addCell = findCell(cellToFind.getX() - 1, cellToFind.getY() +1);
if (addCell != null) {
neighbours.add(addCell);
}
addCell = findCell(cellToFind.getX(), cellToFind.getY() +1);
if (addCell != null) {
neighbours.add(addCell);
}
addCell = findCell(cellToFind.getX() + 1, cellToFind.getY() +1);
if (addCell != null) {
neighbours.add(addCell);
}
return neighbours;

}

@Override
public Collection<ICell> getNeighbours(int x, int y) {
AliveCell ac = new AliveCell();
ac.setX(x);
ac.setY(y);
return getNeighbours(ac);
}

@Override
public void addCell(ICell cell){
if (cell==null) return;
super.addCell(cell);
coll.put(cell, cell);
}

}

The Following blog posts the code for The Game of life

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package gameoflifeiversion;

/**
 *
 * @author noel
 */
public interface ICell extends Comparable{
    @Override
    public int hashCode();
    @Override
    public String toString(); 
    public void setX(int x);
    public void setY(int y);
    public int getX();
    public int getY();
    
    @Override
    public boolean equals(Object c);
    
    @Override
    public int compareTo(ICell cell);
    
}

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package gameoflifeiversion;

/**
 *
 * @author noel
 */
public abstract class AbstractCell implements ICell{
  private int x;
  private int y;
@Override
    public int compareTo(ICell comparison) {
        
        if (this.getY()comparison.getY()) return 1;
        if (this.getY() == comparison.getY()
                && this.getX() < comparison.getX()) return -1;
        if (this.getY() == comparison.getY()
                && this.getX() > comparison.getX()) return 1;
        return 0;
 
    }
 @Override
 public boolean equals(Object obj){
     if (!(obj instanceof AbstractCell)) return false;
    AbstractCell ac = (AbstractCell)obj;
    return ac.getX() == this.getX() && ac.getY() == this.getY();

 }
  
  
  
  
    @Override
  public int hashCode() {
      int returnValue = 0;
        if (x != 0){
            returnValue = x * 31;
            
        }
        if (y!=0){
         returnValue *= y;   
        }
        return returnValue;
        }
    
    /**
     * @return the x
     */
    public int getX() {
        return x;
    }

    /**
     * @param x the x to set
     */
    public void setX(int x) {
        this.x = x;
    }

    /**
     * @return the y
     */
    public int getY() {
        return y;
    }

    /**
     * @param y the y to set
     */
    public void setY(int y) {
        this.y = y;
    }
    public String toCellString(){
        return getX() + "_" + getY();
    }
    
    
}


/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package gameoflifeiversion;

/**
 *
 * @author noel
 */
public class AliveCell extends AbstractCell{
    @Override
    public String toCellString(){
        return "A_"+super.toCellString();
    }

    
    
}

Thursday, March 3, 2011

Overriding hash code and equals in collections


package SDMXDatabaseUploader;

import java.util.HashMap;


public class SDMXSeries {
 public HashMap SeriesKey = new HashMap();

 public HashMap Obs = new HashMap();
 /**
  * Since SeriesKeys have to be unique this is 
  * what defines if an SDMXSeries equals another.
  */
 
 public boolean equals(Object o){
  SDMXSeries comparison = (SDMXSeries)o;
  return SeriesKey.equals(comparison.SeriesKey);

 }
 /**
  * 
  */
 public int hashCode(){
  return SeriesKey.hashCode();

 }

 /**
  * 
  * @param key
  * @param value
  * @throws NullPointerException if key or value is null.
  * @throws DuplicateKeyException if key is repeated.
  */
 public void addSeriesKeyValue(String key, String value)throws NullPointerException, DuplicateKeyException{

  if (key == null || value == null)throw new NullPointerException("Key or Value is null");
  if (SeriesKey.containsKey(key))throw new DuplicateKeyException("Failed trying to add a duplicate key to the series key" + key);
  SeriesKey.put(key, value);

 }
 /**
  * 
  * @param key
  * @param value
  * @throws NullPointerException if key or value is null.
  * @throws DuplicateKeyException if key is repeated.
  */
 public void addObsKeyValue(String key, String value)throws NullPointerException, DuplicateKeyException{

  if (key == null || value == null)throw new NullPointerException("Key or Value is null");
  if (Obs.containsKey(key))throw new DuplicateKeyException("Failed Trying to add a duplicate key to the series key" + key);
  Obs.put(key, value);
 }
 public String toString(){
  return SeriesKey.toString() + " " + Obs.toString();

 }
}

Exception code...


package SDMXDatabaseUploader;

public class DuplicateKeyException extends Exception {

 /**
  * 
  */
 private static final long serialVersionUID = 1L;
public DuplicateKeyException (String message){
 super(message);
}
public DuplicateKeyException (){
super("Failed attempting to add duplicate key."); 

}

}

package SDMXDatabaseUploader;

public class EmptyValueException extends Exception {
 public EmptyValueException (int lineNumber){
  super("Processed Line "+ lineNumber +"has an empty string for one or more entries.");
 }

}

Crypto Utils

This is taken directly from http://www.rgagnon.com/javadetails/java-0400.html

It is wholly this persons work and what follows is a copy for my future reference...


package SDMXDatabaseUploader;
/*
 * Taken directly with thanks from http://www.rgagnon.com/javadetails/java-0400.html
 */
import java.io.File;
import java.io.FileWriter;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.security.GeneralSecurityException;
import java.security.NoSuchAlgorithmException;
import java.util.Scanner;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec; 

public class CryptoUtils {
  
  public static final String AES = "AES";
  
  /**
   * encrypt a value and generate a keyfile 
   * if the keyfile is not found then a new one is created
   * @throws GeneralSecurityException 
   * @throws IOException 
   */
  public static String encrypt(String value, File keyFile)
  throws GeneralSecurityException, IOException 
  {
    if (!keyFile.exists()) {
      KeyGenerator keyGen = KeyGenerator.getInstance(CryptoUtils.AES);
      keyGen.init(128);
      SecretKey sk = keyGen.generateKey();
      FileWriter fw = new FileWriter(keyFile);
      fw.write(byteArrayToHexString(sk.getEncoded()));
      fw.flush();
      fw.close();
    }
    
   SecretKeySpec sks = getSecretKeySpec(keyFile);
   Cipher cipher = Cipher.getInstance(CryptoUtils.AES);
   cipher.init(Cipher.ENCRYPT_MODE, sks, cipher.getParameters());
   byte[] encrypted = cipher.doFinal(value.getBytes());
   return byteArrayToHexString(encrypted);
  }
  
  /**
   * decrypt a value  
   * @throws GeneralSecurityException 
   * @throws IOException 
   */
  public static String decrypt(String message, File keyFile) 
  throws GeneralSecurityException, IOException 
  {
   SecretKeySpec sks = getSecretKeySpec(keyFile);
   Cipher cipher = Cipher.getInstance(CryptoUtils.AES);
   cipher.init(Cipher.DECRYPT_MODE, sks);
   byte[] decrypted = cipher.doFinal(hexStringToByteArray(message));
   return new String(decrypted);
  }
  
  
  
  private static SecretKeySpec getSecretKeySpec(File keyFile) 
  throws NoSuchAlgorithmException, IOException 
  {
    byte [] key = readKeyFile(keyFile);
    SecretKeySpec sks = new SecretKeySpec(key, CryptoUtils.AES);
    return sks;
  }

  private static byte [] readKeyFile(File keyFile) 
  throws FileNotFoundException 
  {
    Scanner scanner = 
      new Scanner(keyFile).useDelimiter("\\Z");
    String keyValue = scanner.next();
    scanner.close();
    return hexStringToByteArray(keyValue);
  }

  
  private static String byteArrayToHexString(byte[] b){
    StringBuffer sb = new StringBuffer(b.length * 2);
    for (int i = 0; i < b.length; i++){
      int v = b[i] & 0xff;
      if (v < 16) {
        sb.append('0');
      }
      sb.append(Integer.toHexString(v));
    }
    return sb.toString().toUpperCase();
}

  private static byte[] hexStringToByteArray(String s) {
    byte[] b = new byte[s.length() / 2];
    for (int i = 0; i < b.length; i++){
      int index = i * 2;
      int v = Integer.parseInt(s.substring(index, index + 2), 16);
      b[i] = (byte)v;
    }
    return b;
}
  
}

Calling code


package JUnitTests;

import java.io.File;
import java.io.IOException;
import java.security.GeneralSecurityException;

import SDMXDatabaseUploader.CryptoUtils;
import junit.framework.Assert;
import junit.framework.TestCase;

public class CryptoUtilsTest extends TestCase {
public void testCrypto(){
 final String KEY_FILE = "./src/crypto.key";
    //final String PWD_FILE = "c:/temp/howto.properties";
    
    String clearPwd= "JUnitTestPassword";
 
   // Properties p1 = new Properties();
    
    //p1.put("user", "Real");
    String encryptedPwd = null;
 try {
  encryptedPwd = CryptoUtils.encrypt(clearPwd, new File(KEY_FILE));
 } catch (GeneralSecurityException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
    //p1.put("pwd", encryptedPwd);
   // p1.store(new FileWriter(PWD_FILE), "");
    
    // ==================
    //Properties p2 = new Properties();
    
    //p2.load(new FileReader(PWD_FILE));
    //encryptedPwd = p2.getProperty("pwd");
    //System.out.println(encryptedPwd);
    try {
  //System.out.println
  //    (CryptoUtils.decrypt(encryptedPwd, new File(KEY_FILE)));
     Assert.assertEquals("Encryption Failed", CryptoUtils.decrypt(encryptedPwd, new File(KEY_FILE)), clearPwd);
 } catch (GeneralSecurityException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
  }

}