Steve Thames

I first encountered this problem about a year ago and found that it was causing many other people trouble. I recently returned to the problem and found a resolution that I thought I would share in the hopes it will help someone else.

The problem, fundamentally, is that Sun, sometime in the past, implemented a generic UI interface that can be easily changed to fit the target environment--Window, Mac, etc. These Motifs can be globally selected and affect all styles used the in the application/applet. The way they did this, in the case of the JTextPane/JEditorPane, was to modify the default style in the StyleContext object (getAttributeContext()) of the document itself. The pane gets its default settings from the default style context.

This may have made sense to someone, for some reason. Personally, I would have set the defaults in the default StyleContext and not have the UI mess with it at all. But that's just me.

The effect of this was to completly short-circuit the mechanism for using styles the way we want to because the JTextPane/JEditorPane will get its font/color attributes from the StyleContext. Since the UI Motif will resent them no matter what you do, the feature is lost.

My solution turned out to be seems like a hack but actually turns out to be rather elegant because it is encapsulated to one object--StyleContext. I created a subclass of StyleContext and use this to create the default document. This subclass watches the default style and resets it to my values whenever it is changed by something else--such as the UI.

Here is the code. I hope someone finds it useful.
/******************************************************************************* * $Id: WSStyleContext.java,v 1.1.2.1 2007/10/26 01:33:05 steve Exp $ * ------------------------------------------------------------------------------ * $Log: WSStyleContext.java,v $ * Revision 1.1.2.1 2007/10/26 01:33:05 steve * Fixed default style context issue. Still testing new Reader/Writer. * *******************************************************************************/ package wsapp.rtf; import java.awt.Color; import java.awt.Font; import javax.swing.event.ChangeEvent; import javax.swing.event.ChangeListener; import javax.swing.text.AttributeSet; import javax.swing.text.SimpleAttributeSet; import javax.swing.text.Style; import javax.swing.text.StyleConstants; import javax.swing.text.StyleContext; import javax.swing.plaf.FontUIResource; /******************************************************************************* * StyleContext for use with Webscriber documents. This object is used to create * a new WSDocument object. It establishes the default style for the document * and protects the style from change by the Java UI. * <p> * In order to create one global setting for UI fonts and other resources, * apparently, the UI modifies the StyleContext of the document to be what the * global setting is. This was really stupid in that it made it nearly * impossible to use the default style for anything other than the UI font or * foreground color. * <p> * This object adds a listener to the default style and restores it to its * default value whenever an attribute changes. Performance should not suffer * since these changes will only be made when the UI modifies the default style. * * @version $Revision: 1.1.2.1 $ *******************************************************************************/ public class WSStyleContext extends StyleContext { /***************************************************************************** * Constants *****************************************************************************/ /** * Attribute key to reference the default font according to Sun source code. * Used in javax.swing.text.StyleContext.getFont() to resolve the default font. * <p> * This turns out not to be the case. This constant is no longer used by * getFont() if it ever was. We maintain it anyway. */ protected static final String FONT_ATTRIBUTE_KEY = "FONT_ATTRIBUTE_KEY"; /***************************************************************************** * Properties *****************************************************************************/ /** Default Style Attributes */ protected SimpleAttributeSet m_Default; /** Restoring Defaults Flag */ protected boolean m_Restoring; /***************************************************************************** * Constructor */ /** * Instantiates the StyleContext. Build the Default Style Attributes and adds * the ChangeListener to the default style. *****************************************************************************/ public WSStyleContext() { super(); Style s = getStyle(StyleContext.DEFAULT_STYLE); /*--------------------------------------*/ /* Create the default style attributes. */ /*--------------------------------------*/ m_Default = new SimpleAttributeSet(s); StyleConstants.setFontFamily(m_Default, "Times New Roman"); StyleConstants.setFontSize (m_Default, 12); StyleConstants.setBold (m_Default, false); StyleConstants.setItalic (m_Default, false); StyleConstants.setForeground(m_Default, Color.black); m_Default.addAttribute(FONT_ATTRIBUTE_KEY, new FontUIResource(getFont(m_Default))); /*-----------------------------------------------------*/ /* Add the default attributes and the change listener. */ /*-----------------------------------------------------*/ s.addAttributes(m_Default); s.addChangeListener(new ChangeListener() { public void stateChanged(ChangeEvent e) { if (m_Restoring) return; Style s = (Style)e.getSource(); synchronized(s) { m_Restoring = true; s.removeAttributes(s); s.addAttributes(m_Default); m_Restoring = false; } } }); } /***************************************************************************** * updateDefault */ /** * Updates the default style with an attribute set. * * @param as Attribute Set *****************************************************************************/ public void updateDefault(AttributeSet as) { m_Default.addAttributes(as); getStyle(StyleContext.DEFAULT_STYLE).addAttributes(m_Default); } }