RegexDocumentFilter.java

package chatty.gui;

import java.util.regex.Pattern;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;

/**
 * A document filter that removes text based on a regular expression.
 * 
 * @author tduva
 */
public class RegexDocumentFilter extends DocumentFilter {
    
    private final Pattern pattern;
    
    public RegexDocumentFilter(String regex) {
        pattern = Pattern.compile(regex);
    }
    
    @Override
    public void insertString(DocumentFilter.FilterBypass fb, int off, String str, AttributeSet attr) {
        try {
            fb.insertString(off, pattern.matcher(str).replaceAll(""), attr);
        } catch (BadLocationException | NullPointerException ex) {
            
        }
    }

    @Override
    public void replace(DocumentFilter.FilterBypass fb, int off, int len, String str, AttributeSet attr) {
        try {
            if (str == null) {
                fb.replace(off, len, str, attr);
            } else {
                fb.replace(off, len, pattern.matcher(str).replaceAll(""), attr);
            }
        } catch (BadLocationException | NullPointerException ex) {
            
        }
    }

}