A DocumentFilter which allows filters to be chained together

ChainedDocumentFilter.java

import java.awt.Component;
import java.awt.KeyboardFocusManager;
import java.awt.Toolkit;
import javax.swing.LookAndFeel;
import javax.swing.UIManager;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.DocumentFilter;
import javax.swing.text.JTextComponent;

/**
 * A single DocumentFilter can be set on an AbstractDocument. There may be times
 * when you wish to perform multiple filtering of the data as it is added to a
 * Document. By extending the ChainedDocumentFilter instead of the
 * DocumentFilter you will receive added flexibility in that the filter can be
 * used stand alone or with other ChainedDocumentFilters.
 *
 * Whenever one filter step fails, the chaining of the filters is also
 * terminated. In this case is it recommended you invoke the
 * provideErrorFeedback() method to provide user feedback.
 */
// Original source https://tips4java.wordpress.com/2009/10/18/chaining-document-filters/
abstract class ChainedDocumentFilter extends DocumentFilter {

    private DocumentFilter filter;

    /**
     * Standard constructor for standalone usage
     */
    public ChainedDocumentFilter() {
        this(null);
    }

    /**
     * Constructor used when further filtering is required after this filter has
     * been applied.
     */
    public ChainedDocumentFilter(DocumentFilter filter) {
        setFilter(filter);
    }

    /**
     * Get the next filter in the chain.
     *
     * @return the next filter in the chain
     */
    public DocumentFilter getFilter() {
        return filter;
    }

    /**
     * Set the next filter in the chain
     *
     * @param filter
     */
    public void setFilter(DocumentFilter filter) {
        this.filter = filter;
    }

    /**
     * Install this filter on the AbstractDocument
     *
     * @param components the text components that will use this filter
     */
    public void installFilter(JTextComponent... components) {
        for (JTextComponent component : components) {
            Document doc = component.getDocument();

            if (doc instanceof AbstractDocument) {
                ((AbstractDocument) doc).setDocumentFilter(this);
            }
        }
    }

    /**
     * Remove this filter from the AbstractDocument
     *
     * @param compoents remove the filter from the specified text components
     */
    public void uninstallFilter(JTextComponent... components) {
        for (JTextComponent component : components) {
            Document doc = component.getDocument();

            if (doc instanceof AbstractDocument) {
                ((AbstractDocument) doc).setDocumentFilter(null);
            }
        }
    }

    /**
     * Provide appropriate LAF feedback when a filter error occurs.
     */
    protected void provideErrorFeedback() {
        LookAndFeel laf = UIManager.getLookAndFeel();

        if (laf == null) {
            Toolkit.getDefaultToolkit().beep();
        } else {
            KeyboardFocusManager fm = KeyboardFocusManager.getCurrentKeyboardFocusManager();
            Component component = fm.getFocusOwner();
            laf.provideErrorFeedback(component);
        }
    }

    @Override
    public void insertString(DocumentFilter.FilterBypass fb, int offs, String str, AttributeSet a)
            throws BadLocationException {
        if (filter == null) {
            super.insertString(fb, offs, str, a);
        } else {
            filter.insertString(fb, offs, str, a);
        }
    }

    @Override
    public void replace(DocumentFilter.FilterBypass fb, int offs, int length, String str, AttributeSet a)
            throws BadLocationException {
        if (filter == null) {
            super.replace(fb, offs, length, str, a);
        } else {
            filter.replace(fb, offs, length, str, a);
        }
    }

    @Override
    public void remove(DocumentFilter.FilterBypass fb, int offset, int length)
            throws BadLocationException {
        if (filter == null) {
            super.remove(fb, offset, length);
        } else {
            filter.remove(fb, offset, length);
        }
    }
}