Java Swing - Getting notifications on cut, copy, and paste actions for text components.

Following code shows how to get notified on copy, paste or cut actions for a JTextComponent. In other words this will intercept cut/copy/paste actions.

package com.logicbig.example;

import javax.swing.*;
import javax.swing.text.JTextComponent;
import java.awt.*;
import java.awt.datatransfer.DataFlavor;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.util.function.BiConsumer;

public class CutCopyPasteListenerUtil {
  public static final String COPY = "COPY";
  public static final String CUT = "CUT";
  public static final String PASTE = "PASTE";

  public static void addCutCopyPasteInterceptor(JTextComponent tc, BiConsumer<String, String> listener) {

      tc.registerKeyboardAction(ae -> handlePaste(tc, listener),
              KeyStroke.getKeyStroke(KeyEvent.VK_V, InputEvent.CTRL_DOWN_MASK), JComponent.WHEN_FOCUSED);

      tc.registerKeyboardAction(ae -> handleCopy(tc, listener),
              KeyStroke.getKeyStroke(KeyEvent.VK_C, InputEvent.CTRL_DOWN_MASK), JComponent.WHEN_FOCUSED);

      tc.registerKeyboardAction(ae -> handleCut(tc, listener),
              KeyStroke.getKeyStroke(KeyEvent.VK_X, InputEvent.CTRL_DOWN_MASK), JComponent.WHEN_FOCUSED);
  }

  private static void handlePaste(JTextComponent tc,
                                  BiConsumer<String, String> listener) {
      try {
          String s = (String) Toolkit.getDefaultToolkit()
                                     .getSystemClipboard()
                                     .getData(DataFlavor.stringFlavor);
          tc.paste();
          listener.accept(PASTE, s);

      } catch (Exception e) {
          System.err.println(e);
      }
  }

  private static void handleCopy(JTextComponent tc, BiConsumer<String, String> listener) {
      String s = tc.getSelectedText();
      tc.copy();
      listener.accept(COPY, s);
  }

  private static void handleCut(JTextComponent tc, BiConsumer<String, String> listener) {
      String s = tc.getSelectedText();
      tc.cut();
      listener.accept(CUT, s);
  }

  public static void main(String[] args) {
      JTextArea ta = new JTextArea(5, 5);
      addCutCopyPasteInterceptor(ta, (type, text) -> {
          System.out.printf("action type: %s, action text: %s %n", type, text);
      });
      JFrame frame = createFrame("Intercepting cut copy paste");
      frame.add(new JScrollPane(ta));
      frame.setVisible(true);
  }

  public static JFrame createFrame(String title) {
      JFrame frame = new JFrame(title);
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setSize(new Dimension(800, 700));
      return frame;
  }
}

Example Project

Dependencies and Technologies Used:

• JDK 10
• Maven 3.3.9