FileDocCategorySizeDatePackage
StringCutAndPaste.javaAPI DocExample3768Sat Jun 02 02:44:08 BST 2001None

StringCutAndPaste

public class StringCutAndPaste extends Frame implements ActionListener
This program demonstrates how to add string cut-and-paste capabilities to an application.

Fields Summary
TextField
field
The text field that holds the text that is cut or pasted
Constructors Summary
public StringCutAndPaste()
The constructor builds a very simple test GUI, and registers this object as the ActionListener for the buttons

    this.setFont(new Font("SansSerif", Font.PLAIN, 14));  // Use a nice font

    // Set up the Cut button
    Button cut = new Button("Cut");                       
    cut.addActionListener(this);
    cut.setActionCommand("cut");
    this.add(cut, "West");

    // Set up the Paste button
    Button paste = new Button("Paste");
    paste.addActionListener(this);
    paste.setActionCommand("paste");
    this.add(paste, "East");

    // Set up the text field that they both operate on
    field = new TextField();
    this.add(field, "North");
Methods Summary
public voidactionPerformed(java.awt.event.ActionEvent e)
Clicking on one of the buttons invokes this method, which in turn invokes either the cut() or the paste() method

    String cmd = e.getActionCommand();
    if (cmd.equals("cut")) cut();
    else if (cmd.equals("paste")) paste();
public voidcut()
This method takes the current contents of the text field, creates a StringSelection object to represent that string, and puts the StringSelection onto the clipboard

    // Get the currently displayed value
    String s = field.getText();                  

    // Create a StringSelection object to represent it.
    // This is a big convenience, because StringSelection implements both
    // the Transferable interface and the ClipboardOwner.  We don't have
    // to deal with either of them.
    StringSelection ss = new StringSelection(s); 

    // Now set the StringSelection object as the contents of the clipboard
    // Also set it as the owner of the clipboard.
    this.getToolkit().getSystemClipboard().setContents(ss, ss);
public static voidmain(java.lang.String[] args)
The main method creates a frame, arranges to handle its closing, packs it and pops it up.

    Frame f = new StringCutAndPaste();
    f.addWindowListener(new WindowAdapter() { 
      public void windowClosing(WindowEvent e) { System.exit(0); }
    });
    f.pack();
    f.show();
public voidpaste()
This method does the reverse. It gets the contents of the clipboard, then asks for them to be converted to a string, then displays the string.

    // Get the clipboard
    Clipboard c = this.getToolkit().getSystemClipboard();

    // Get the contents of the clipboard, as a Transferable object
    Transferable t = c.getContents(this);

    // Ask for the transferable data in string form, using the predefined
    // string DataFlavor.  Then display that string in the field.
    try { 
      String s = (String) t.getTransferData(DataFlavor.stringFlavor);
      field.setText(s); 
    }
    // If anything goes wrong with the transfer, just beep and do nothing.
    catch (Exception e) { 
      this.getToolkit().beep();
      return;
    }