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