105 lines
3.6 KiB
Java
105 lines
3.6 KiB
Java
import java.awt.*;
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import java.awt.event.*;
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import javax.swing.*;
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/**
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* Class CaseConverter - A simple applet that takes input from a text field
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* and converts to upper or lower case in response to user button selection.
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* Works well with a width of 300 and height of 120.
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*
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* Aug 2004: Updated from Applet to JApplet (mik)
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*
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* @author Bruce Quig
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* @author Michael Kolling
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*
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* @version 2004-08-04
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*/
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public class CaseConverter extends JApplet
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implements ActionListener
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{
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private JTextField inputField;
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private final String UPPERCASE = "UPPERCASE";
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private final String LOWERCASE = "lowercase";
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private final String CLEAR = "Clear";
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/**
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* Called by the browser or applet viewer to inform this JApplet that it
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* has been loaded into the system. It is always called before the first
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* time that the start method is called.
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*/
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public void init()
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{
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// GUI elements are added to the applet's content pane, so get it for us.
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Container contentPane = getContentPane();
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// set a layout with some spacing
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contentPane.setLayout(new BorderLayout(12,12));
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// add the title label
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JLabel title = new JLabel("Case Converter - A BlueJ demo applet");
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contentPane.add(title, BorderLayout.NORTH);
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// create the center part with prompt and text field and add it
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JPanel centerPanel = new JPanel();
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JLabel prompt = new JLabel("Enter a string:");
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centerPanel.add(prompt);
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inputField = new JTextField(16);
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centerPanel.add(inputField);
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contentPane.add(centerPanel, BorderLayout.CENTER);
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// make a panel for the buttons
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JPanel buttonPanel = new JPanel();
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// add the buttons to the button panel
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JButton uppercase = new JButton(UPPERCASE);
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uppercase.addActionListener(this);
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buttonPanel.add(uppercase);
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JButton lowercase = new JButton(LOWERCASE);
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lowercase.addActionListener(this);
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buttonPanel.add(lowercase);
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JButton clear = new JButton(CLEAR);
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clear.addActionListener(this);
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buttonPanel.add(clear);
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// add the buttons panel to the content pane
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contentPane.add(buttonPanel, BorderLayout.SOUTH);
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}
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/**
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* Returns information about this applet.
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* An applet should override this method to return a String containing
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* information about the author, version, and copyright of the JApplet.
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*
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* @return a String representation of information about this JApplet
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*/
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public String getAppletInfo()
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{
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return "Title: Case Converter \n" +
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"Author: Bruce Quig \n" +
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"A simple applet that converts text to upper or lower case. ";
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}
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/**
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* ActionListener Interface method.
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* Called when action events occur with registered components that
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* can fire action events.
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* @param ae the ActionEvent object created by the event
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*/
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public void actionPerformed(ActionEvent evt)
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{
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String command = evt.getActionCommand();
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// if clear button pressed
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if(CLEAR.equals(command))
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inputField.setText("");
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// uppercase button pressed
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else if(UPPERCASE.equals(command))
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inputField.setText(inputField.getText().toUpperCase());
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// lowercase button pressed
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else if(LOWERCASE.equals(command))
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inputField.setText(inputField.getText().toLowerCase());
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}
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}
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