Java/Design Pattern/Prototype Pattern

Prototype pattern in Java

   <source lang="java">

/* The Design Patterns Java Companion Copyright (C) 1998, by James W. Cooper IBM Thomas J. Watson Research Center

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import java.awt.Button; import java.awt.Color; import java.awt.Frame; import java.awt.GridLayout; import java.awt.List; import java.awt.Panel; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.RandomAccessFile; import java.io.Serializable; import java.util.StringTokenizer; import java.util.Vector; public class SwimInfo extends Frame implements ActionListener {

 SwimData sdata, sxdata = null;
 List swList, cloneList;
 Button Clone, Refresh, Quit;
 Swimmer sw;
 public SwimInfo() {
   super("Prototype example");
   sdata = new SwimData("swimmers.txt");
   setGUI();
   loadswList();
 }
 //-
 public void actionPerformed(ActionEvent e) {
   Object obj = e.getSource();
   if (obj == Clone)
     cloneAndLoad();
   if (obj == Refresh)
     loadswList();
   if (obj == Quit)
     System.exit(0);
 }
 //-
 private void cloneAndLoad() {
   //sxdata = (SwimData)sdata.deepClone();
   sxdata = (SwimData) sdata.clone();
   sxdata.sortByTime();
   cloneList.removeAll();
   //now print out sorted values from clone
   for (int i = 0; i < sxdata.size(); i++) {
     sw = sxdata.getSwimmer(i);
     cloneList.addItem(sw.getName() + " " + sw.getTime());
   }
 }
 //-
 private void loadswList() {
   swList.removeAll();
   for (int i = 0; i < sdata.size(); i++) {
     sw = sdata.getSwimmer(i);
     swList.addItem(sw.getName() + " " + sw.getTime());
   }
 }
 //-
 private void setGUI() {
   setLayout(new GridLayout(1, 3));
   setBackground(Color.lightGray);
   swList = new List(15);
   cloneList = new List(15);
   Panel cp = new Panel();
   add(swList);
   add(cp);
   add(cloneList);
   Clone = new Button("Clone >");
   Refresh = new Button("<Refresh");
   Quit = new Button("Quit");
   cp.setLayout(new GridLayout(3, 1));
   Panel p1 = new Panel();
   cp.add(p1);
   p1.add(Clone);
   Panel p2 = new Panel();
   cp.add(p2);
   p2.add(Refresh);
   Panel p3 = new Panel();
   cp.add(p3);
   p3.add(Quit);
   Clone.addActionListener(this);
   Refresh.addActionListener(this);
   Quit.addActionListener(this);
   setBounds(100, 100, 500, 400);
   setVisible(true);
 }
 //-
 static public void main(String argv[]) {
   new SwimInfo();
 }

} class SwimmerNoSex extends SwimData {

 public SwimmerNoSex(String fileName) {
     super(fileName);
 }
 public void sortByTime() {
 }

} class SwimData implements Cloneable, Serializable {

 protected Vector swimmers;
 public SwimData(String filename) {
   String s = "";
   swimmers = new Vector();
   InputFile f = new InputFile(filename);
   s = f.readLine();
   while (s != null) {
     swimmers.addElement(new Swimmer(s));
     s = f.readLine();
   }
   f.close();
 }
 
 public int size() {
   return swimmers.size();
 }
 
 public Swimmer getSwimmer(int i) {
   if ((i >= 0) && (i < swimmers.size()))
     return (Swimmer) swimmers.elementAt(i);
   else
     return null;
 }
 
 public void sortByTime() {
   Swimmer sw;
   int i, j;
   int max = swimmers.size();
   Swimmer sd[] = new Swimmer[max];
   for (i = 0; i < max; i++)
     sd[i] = (Swimmer) swimmers.elementAt(i);
   for (i = 0; i < max; i++) {
     for (j = i; j < max; j++) {
       if (sd[i].getTime() > sd[j].getTime()) {
         sw = sd[i];
         sd[i] = sd[j];
         sd[j] = sw;
       }
     }
   }
   // swimmers = new Vector();
   swimmers.removeAllElements();
   for (i = 0; i < max; i++)
     swimmers.addElement(sd[i]);
 }
 
 public Object deepClone() {
   try {
     ByteArrayOutputStream b = new ByteArrayOutputStream();
     ObjectOutputStream out = new ObjectOutputStream(b);
     out.writeObject(this);
     ByteArrayInputStream bIn = new ByteArrayInputStream(b.toByteArray());
     ObjectInputStream oi = new ObjectInputStream(bIn);
     return (oi.readObject());
   } catch (Exception e) {
     System.out.println("exception:" + e.getMessage());
     e.printStackTrace();
     return null;
   }
 }
 
 public Object clone() {
   try {
     return super.clone();
   } catch (Exception e) {
     System.out.println(e.getMessage());
     return null;
   }
 }

} //============================================== class Swimmer implements Serializable {

 String name;
 int age;
 String club;
 float time;
 boolean female;
 public Swimmer(String dataline) {
   StringTokenizer st = new StringTokenizer(dataline, ",");
   name = st.nextToken();
   age = new Integer(st.nextToken().trim()).intValue();
   club = st.nextToken().trim();
   time = new Float(st.nextToken().trim()).floatValue();
   //System.out.println(name+" "+time);
   String sx = st.nextToken().trim().toUpperCase();
   female = sx.equals("F");
 }
 public boolean isFemale() {
   return female;
 }
 public int getAge() {
   return age;
 }
 public float getTime() {
   return time;
 }
 public String getName() {
   return name;
 }
 public String getClub() {
   return club;
 }

} class InputFile {

 RandomAccessFile f = null;
 boolean errflag;
 String s = null;
 public InputFile(String fname) {
   errflag = false;
   try {
     //open file
     f = new RandomAccessFile(fname, "r");
   } catch (IOException e) {
     //print error if not found
     System.out.println("no file found");
     errflag = true; //and set flag
   }
 }
 
 public boolean checkErr() {
   return errflag;
 }
 
 public String read() {
   //read a single field up to a comma or end of line
   String ret = "";
   if (s == null) //if no data in string
   {
     s = readLine(); //read next line
   }
   if (s != null) //if there is data
   {
     s.trim(); //trim off blanks
     int i = s.indexOf(","); //find next comma
     if (i <= 0) {
       ret = s.trim(); //if no commas go to end of line
       s = null; //and null out stored string
     } else {
       ret = s.substring(0, i).trim(); //return left of comma
       s = s.substring(i + 1); //save right of comma
     }
   } else
     ret = null;
   return ret; //return string
 }
 
 public String readLine() {
   //read in a line from the file
   s = null;
   try {
     s = f.readLine(); //could throw error
   } catch (IOException e) {
     errflag = true;
     System.out.println("File read error");
   }
   return s;
 }
 
 public void close() {
   try {
     f.close(); //close file
   } catch (IOException e) {
     System.out.println("File close error");
     errflag = true;
   }
 }
 

} //Swimmers.txt /* Kristen Frost, 9, CAT, 26.31, F Kimberly Watcke, 10, CDEV,27.37, F Jaclyn Carey, 10, ARAC, 27.53, F Megan Crapster, 10, LEHY, 27.68, F Kaitlyn Ament, 10, HNHS, 28.20, F Jackie Rogers, 10, WCA, 28.68, F Erin McLaughlin, 9, HMST, 28.80, F Emily Ferrier, 10, NMIL, 28.85, F Aurora Lee, 8, FFLY, 28.88, F Kate Isselee, 9, NMIL, 28.91, F Luke Mester, 10, GYWD, 24.88, M Stephen Cosme, 9, OAK, 27.89, M Jeffrey Sudbury, 10, WYW, 28.24, M Ernest Verrico, 9, SHKS, 28.46, M David Liebovitz, 10, WYW, 28.78, M Ryan Rynazewski, 10, AJSC, 28.83, M Matthew Donch, 9, PSDY, 28.95, M Christopher Prus, 10, RAYS, 29.02, M Charles Baker, 10, PSDY, 29.06, M Matthew Sweitzer, 10, SHKS, 29.10, M

• /

      </source>
   
  
 
  

Prototype Pattern in Java 2

   <source lang="java">

//[C] 2002 Sun Microsystems, Inc.---

public class RunPrototypePattern {

 public static void main(String[] arguments) {
   System.out.println("Example for Prototype pattern");
   System.out.println();
   System.out.println("This example will create an Address object,");
   System.out.println(" which it will then duplicate by calling the");
   System.out.println(" object"s clone method.");
   System.out.println();
   System.out.println("Creating first address.");
   Address address1 = new Address("8445 Silverado Trail", "Rutherford",
       "CA", "91734");
   System.out.println("First address created.");
   System.out.println("    Hash code = " + address1.hashCode());
   System.out.println(address1);
   System.out.println();
   System.out.println("Creating second address using the clone() method.");
   Address address2 = (Address) address1.copy();
   System.out.println("Second address created.");
   System.out.println("    Hash code = " + address2.hashCode());
   System.out.println(address2);
   System.out.println();
 }

} interface Copyable {

 public Object copy();

} class Address implements Copyable {

 private String type;
 private String street;
 private String city;
 private String state;
 private String zipCode;
 public static final String EOL_STRING = System
     .getProperty("line.separator");
 public static final String COMMA = ",";
 public static final String HOME = "home";
 public static final String WORK = "work";
 public Address(String initType, String initStreet, String initCity,
     String initState, String initZip) {
   type = initType;
   street = initStreet;
   city = initCity;
   state = initState;
   zipCode = initZip;
 }
 public Address(String initStreet, String initCity, String initState,
     String initZip) {
   this(WORK, initStreet, initCity, initState, initZip);
 }
 public Address(String initType) {
   type = initType;
 }
 public Address() {
 }
 public String getType() {
   return type;
 }
 public String getStreet() {
   return street;
 }
 public String getCity() {
   return city;
 }
 public String getState() {
   return state;
 }
 public String getZipCode() {
   return zipCode;
 }
 public void setType(String newType) {
   type = newType;
 }
 public void setStreet(String newStreet) {
   street = newStreet;
 }
 public void setCity(String newCity) {
   city = newCity;
 }
 public void setState(String newState) {
   state = newState;
 }
 public void setZipCode(String newZip) {
   zipCode = newZip;
 }
 public Object copy() {
   return new Address(street, city, state, zipCode);
 }
 public String toString() {
   return "\t" + street + COMMA + " " + EOL_STRING + "\t" + city + COMMA
       + " " + state + " " + zipCode;
 }

}

      </source>