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POCreate generic class for java program
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  1. POCreate generic class for java program
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    copied!<p>I have written a class in Java for JTextField Focus Listener and I don't know how to write this class as generic class. Once I wrote the generic class it should be used by all the JTextFields how can I do this please tell me the way through coding. How to write a generic class for this following code:</p> <pre><code>package javaapplication7; import java.awt.FlowLayout; import java.awt.event.FocusAdapter; import java.awt.event.FocusEvent; import javax.swing.JFrame; import javax.swing.JTextField; import javax.swing.text.JTextComponent; public class testfocuss{ public static void main(String[] argv) throws Exception { JTextField component = new JTextField(20); JTextField component1 = new JTextField(20); JTextField component2 = new JTextField(20); JTextField component3 = new JTextField(20); component.addFocusListener(new MyFocusListener()); component1.addFocusListener(new MyFocusListener()); component2.addFocusListener(new MyFocusListener()); component3.addFocusListener(new MyFocusListener()); JFrame f = new JFrame(); f.layout(new FlowLayout()); f.add(component1); f.add(component); f.add(component2); f.add(component3); f.pack(); f.setVisible(true); } } class MyFocusListener extends FocusAdapter { //boolean showingDialog = false; public void focusGained(FocusEvent evt) { final JTextComponent c = (JTextComponent) evt.getSource(); String s = c.getText(); c.requestFocus(); c.selectAll(); for (int i = 0; i &lt; s.length(); i++) { if (!Character.isDigit(s.charAt(i))) { c.setSelectionStart(i); c.setSelectionEnd(i); break; } } } public void focusLost(FocusEvent evt) { final JTextComponent c = (JTextComponent) evt.getSource(); String s = c.getText(); if (evt.isTemporary()) { return; } for (int i = 0; i &lt; s.length(); i++) { if (!Character.isDigit(s.charAt(i))) { //System.out.println("must only contain digits"); c.requestFocus(); c.selectAll(); break; } } } } </code></pre>
 

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