Bridge pattern in Java : Bridge Pattern « Design Pattern « Java
Bridge pattern in Java
/*
The Design Patterns Java Companion
Copyright (C) 1998, by James W. Cooper
IBM Thomas J. Watson Research Center
*/
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.Vector;
import javax.swing.AbstractListModel;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.event.TableModelListener;
import javax.swing.table.TableModel;
public class productDisplay extends JFrame {
public productDisplay() {
super("The Java Factory-- Products");
setLF(); //set look and feel
setCloseClick(); //set close on window close click
InputFile f = new InputFile("products.txt");
Vector prod = new Vector();
//read in product list
String s = f.readLine();
while (s != null) {
prod.addElement(s);
s = f.readLine();
}
JPanel p = new JPanel();
getContentPane().add(p);
p.setLayout(new GridLayout(1, 2));
JPanel pleft = new JPanel();
JPanel pright = new JPanel();
p.add(pleft);
p.add(pright);
pleft.setLayout(new BorderLayout());
pright.setLayout(new BorderLayout());
//add in customer view as list box
pleft.add("North", new JLabel("Customer view"));
pleft.add("Center", new productList(prod));
//add in execute view as table
pright.add("North", new JLabel("Executive view"));
pright.add("Center", new productTable(prod));
setSize(new Dimension(400, 300));
setVisible(true);
}
//-----------------------------------------
private void setCloseClick() {
//create window listener to respond to window close click
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
//------------------------------------------
private void setLF() {
// Force SwingApp to come up in the System L&F
String laf = UIManager.getSystemLookAndFeelClassName();
try {
UIManager.setLookAndFeel(laf);
} catch (UnsupportedLookAndFeelException exc) {
System.err.println("Warning: UnsupportedLookAndFeel: " + laf);
} catch (Exception exc) {
System.err.println("Error loading " + laf + ": " + exc);
}
}
//---------------------------------------------
static public void main(String argv[]) {
new productDisplay();
}
}
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;
}
}
//-----------------------------------------
}
class productList extends JawtList {
public productList(Vector products) {
super(products.size()); //for compatibility
for (int i = 0; i < products.size(); i++) {
//take each strig apart and keep only
//the product names, discarding the quntities
String s = (String) products.elementAt(i);
int index = s.indexOf("--"); //separate qty from name
if (index > 0)
add(s.substring(0, index));
else
add(s);
}
}
}
class productTable extends JScrollPane {
JTable table;
public productTable(Vector list) {
table = new JTable(new prodModel(list));
getViewport().add(table);
}
}
class prodModel implements TableModel {
int rows, columns;
Vector prodNames, quantities;
public prodModel(Vector products) {
rows = products.size();
columns = 2;
prodNames = new Vector();
quantities = new Vector();
for (int i = 0; i < products.size(); i++) {
String s = (String) products.elementAt(i);
int index = s.indexOf("--"); //separate qty from name
if (index > 0) {
prodNames.addElement(s.substring(0, index));
quantities.addElement(s.substring(index + 2).trim());
} else
prodNames.addElement(s);
}
}
public int getColumnCount() {
return columns;
}
public int getRowCount() {
return rows;
}
public Object getValueAt(int r, int c) {
switch (c) {
case 0:
return prodNames.elementAt(r);
case 1:
return quantities.elementAt(r);
default:
return prodNames.elementAt(r);
}
}
public Class getColumnClass(int c) {
return (new String("")).getClass();
}
public boolean isCellEditable(int r, int c) {
return false;
}
public String getColumnName(int c) {
return "";
}
public void setValueAt(Object obj, int r, int c) {
}
public void addTableModelListener(TableModelListener tbm) {
}
public void removeTableModelListener(TableModelListener tbm) {
}
}
//this is a simple adapter class to
//convert List awt methods to Swing methods
class JawtList extends JScrollPane implements ListSelectionListener, awtList {
private JList listWindow;
private JListData listContents;
//-----------------------------------------
public JawtList(int rows) {
listContents = new JListData();
listWindow = new JList(listContents);
listWindow.setPrototypeCellValue("Abcdefg Hijkmnop");
getViewport().add(listWindow);
}
//-----------------------------------------
public void add(String s) {
listContents.addElement(s);
}
//-----------------------------------------
public void remove(String s) {
listContents.removeElement(s);
}
//-----------------------------------------
public String[] getSelectedItems() {
Object[] obj = listWindow.getSelectedValues();
String[] s = new String[obj.length];
for (int i = 0; i < obj.length; i++)
s[i] = obj[i].toString();
return s;
}
//-----------------------------------------
public void valueChanged(ListSelectionEvent e) {
}
}
// =========================================
class JListData extends AbstractListModel {
private Vector data;
//-----------------------------------------
public JListData() {
data = new Vector();
}
//-----------------------------------------
public int getSize() {
return data.size();
}
//-----------------------------------------
public Object getElementAt(int index) {
return data.elementAt(index);
}
//-----------------------------------------
public void addElement(String s) {
data.addElement(s);
fireIntervalAdded(this, data.size() - 1, data.size());
}
//-----------------------------------------
public void removeElement(String s) {
data.removeElement(s);
fireIntervalRemoved(this, 0, data.size());
}
}
interface awtList {
public void add(String s);
public void remove(String s);
public String[] getSelectedItems();
}
//products.txt
/*
Brass plated widgets --1,000,076
Furled frammis --75,000
Detailed rat brushes --700
Zero-based hex dumps--80,000
Anterior antelope collars --578
Washable softwear --789,000
Steel-toed wing-tips --456,666
*/
Related examples in the same category
| 1. | Bridge Pattern 1 | ||
| 2. | Bridge Pattern in Java 3 |  |