Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.awt.event.ActionEvent;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.text.JTextComponent;
import javax.swing.text.NavigationFilter;
import javax.swing.text.Position;

public class Main {

    public static void main(String[] args) throws Exception {
        JTextField textField = new JTextField("Prefix_", 20);
        textField.setNavigationFilter(new NavigationFilterPrefixWithBackspace(7, textField));
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(textField);
        frame.pack();
        frame.setVisible(true);
    }
}

class NavigationFilterPrefixWithBackspace extends NavigationFilter {

    private int prefixLength;
    private Action deletePrevious;

    public NavigationFilterPrefixWithBackspace(int prefixLength, JTextComponent component) {
        this.prefixLength = prefixLength;
        deletePrevious = component.getActionMap().get("delete-previous");
        component.getActionMap().put("delete-previous", new BackspaceAction());
        component.setCaretPosition(prefixLength);
    }

    @Override
    public void setDot(NavigationFilter.FilterBypass fb, int dot, Position.Bias bias) {
        fb.setDot(Math.max(dot, prefixLength), bias);
    }

    @Override
    public void moveDot(NavigationFilter.FilterBypass fb, int dot, Position.Bias bias) {
        fb.moveDot(Math.max(dot, prefixLength), bias);
    }

    class BackspaceAction extends AbstractAction {
        public void actionPerformed(ActionEvent e) {
            JTextComponent component = (JTextComponent) e.getSource();
            if (component.getCaretPosition() > prefixLength) {
                deletePrevious.actionPerformed(null);
            }
        }
    }

}