This is a basic approach to syntax highlighting * using regular expressions. It is used to make the plain * HTML view of application SimplyHTML more legible by * separating tags and attributes from content.
* *The method doing the actual highlighting work * is put into an implementation of the Runnable interface * so that it can be called without conflicts.
* *Can be refined in the way Patterns are set up, i.e. * not hard wire pattern setup and a GUI to let the * use choose styles for patterns.
* *Recommended readings:
* 'Regular Expressions and the JavaTM Programming Language' at
* http://developer.java.sun.com/developer/technicalArticles/releases/1.4regex/
* and
* Presentation slides 'Rich Clients for Web Services' from JavaOne 2002 at
* http://servlet.java.sun.com/javaone/resources/content/sf2002/conf/sessions/pdfs/2274.pdf
*
SyntaxPane.
*/
public SyntaxPane() {
super();
setEditorKit(new StyledEditorKit());
setupPatterns();
}
/**
* set up HTML patterns and attributes
*/
private void setupPatterns() {
Pattern p;
SimpleAttributeSet set;
patterns = new Vector();
// content text
p = Pattern.compile("\\b\\w+");
set = new SimpleAttributeSet();
StyleConstants.setForeground(set, Color.BLACK);
StyleConstants.setBold(set, false);
patterns.addElement(new RegExStyle(p, set));
// a tag
p = Pattern.compile("<[/a-zA-Z0-9\\s]+");
set = new SimpleAttributeSet();
StyleConstants.setForeground(set, new Color(0, 0, 128));
StyleConstants.setBold(set, true);
patterns.addElement(new RegExStyle(p, set));
// a tag end
p = Pattern.compile(">");
patterns.addElement(new RegExStyle(p, set));
// an attribute
p = Pattern.compile("\\s[/a-zA-Z0-9]+=");
set = new SimpleAttributeSet();
StyleConstants.setForeground(set, new Color(158, 119, 0));
StyleConstants.setBold(set, true);
patterns.addElement(new RegExStyle(p, set));
// attribute values
p = Pattern.compile("\"[\\x2D;:/.%#?=,\\w\\s]+\"");
set = new SimpleAttributeSet();
StyleConstants.setForeground(set, Color.BLUE);
StyleConstants.setBold(set, false);
patterns.addElement(new RegExStyle(p, set));
}
/**
* apply syntax highlighting to all HTML tags found in the given
* area of the given document
*
* @param doc the document to apply syntax highlighting to
* @param offset the position inside the given document to start to apply syntax highlighting to
* @param len the number of characters to apply syntax highlighting to
*/
public void setMarks(final StyledDocument sDoc, final int offset, final int len) {
SwingUtilities.invokeLater(new StyleUpdater(this, sDoc, offset, len));
}
/**
* overridden from JEditorPane
* to suppress line wraps
*
* @see setSize
*/
public boolean getScrollableTracksViewportWidth() {
return false;
}
/**
* overridden from JEditorPane
* to suppress line wraps
*
* @see getScrollableTracksViewportWidth
*/
public void setSize(final Dimension d) {
if (d.width < getParent().getSize().width) {
d.width = getParent().getSize().width;
}
super.setSize(d);
}
/**
* display a wait cursor for lengthy operations
*/
private void cursor() {
final JRootPane rootPane = getRootPane();
if (rootPane != null) {
final Component gp = rootPane.getGlassPane();
if (!gp.isVisible()) {
gp.setCursor(waitCursor);
gp.setVisible(true);
}
else {
gp.setVisible(false);
}
}
}
/**
* StyleUpdater does the actual syntax highlighting work
* and can be used in SwingUtilities.invokeLater()
*/
private class StyleUpdater implements Runnable {
/**
* construct a StyleUpdater
*
* @param sp the SyntaxPane this StyleUpdater works on
* @param doc the document to apply syntax highlighting to
* @param offset the position inside the given document to start to apply syntax highlighting to
* @param len the number of characters to apply syntax highlighting to
*/
public StyleUpdater(final SyntaxPane sp, final StyledDocument doc, final int offset, final int len) {
sDoc = doc;
this.offset = offset;
this.len = len;
this.sp = sp;
}
/**
* apply snytax highlighting
*/
public void run() {
Matcher m;
RegExStyle style;
cursor();
sp.removeCaretListener(sp);
try {
final int length = sDoc.getLength();
if (length > 0 && len > 0) {
final String text = sDoc.getText(offset, len);
if (text != null && text.length() > 0) {
final Enumeration pe = patterns.elements();
while (pe.hasMoreElements()) {
style = (RegExStyle) pe.nextElement();
m = style.getPattern().matcher(text);
while (m.find()) {
sDoc.setCharacterAttributes(offset + m.start(), m.end() - m.start(), style.getStyle(),
true);
}
}
}
}
}
catch (final Exception ex) {
System.out.println("StyleUpdater ERROR: " + ex.getMessage());
}
sp.addCaretListener(sp);
cursor();
}
/** the document to apply syntax highlighting to */
private final StyledDocument sDoc;
/** the position inside the given document to start to apply syntax highlighting to */
private final int offset;
/** the number of characters to apply syntax highlighting to */
private final int len;
/** the SyntaxPane this StyleUpdater works on */
private final SyntaxPane sp;
}
/**
* CaretListener implementation
*
* updates syntax highlighting for the current line * when the caret moves
*/ public void caretUpdate(final CaretEvent e) { try { final StyledDocument sDoc = (StyledDocument) getDocument(); final int cPos = e.getDot(); final int length = sDoc.getLength(); final String text = sDoc.getText(0, length); final int lineStart = text.substring(0, cPos).lastIndexOf("\n") + 1; int lineEnd = text.indexOf("\n", cPos); if (lineEnd < 0) { lineEnd = length; } setMarks(sDoc, lineStart, lineEnd - lineStart); } catch (final Exception ex) { } } /** * overridden to keep caret changes during the initial text load * from triggering syntax highlighting repetitively */ public void setText(final String t) { removeCaretListener(this); super.setText(t); final StyledDocument sDoc = (StyledDocument) getDocument(); setMarks(sDoc, 0, sDoc.getLength()); setCaretPosition(0); addCaretListener(this); } /** * convenience class associating a pattern with a * set of attributes */ class RegExStyle { /** * construct aRegExStyle instance
*
* @param p the Pattern to apply this style to
* @param a the attributes making up this style
*/
public RegExStyle(final Pattern p, final AttributeSet a) {
this.p = p;
this.a = a;
}
/**
* get the Pattern this style is to be applied to
*
* @return the Pattern
*/
public Pattern getPattern() {
return p;
}
/**
* get the attributes making up this style
*
* @return the set of attributes
*/
public AttributeSet getStyle() {
return a;
}
/**
* set the Pattern to apply a given set of attributes to
*
* @param p the Pattern
*/
public void setPattern(final Pattern p) {
this.p = p;
}
/**
* set the set of attributes to apply to a given Pattern
*
* @param a the set of attributes to use
*/
public void setStyle(final AttributeSet a) {
this.a = a;
}
/** the Pattern to apply this style to */
private Pattern p;
/** the attributes making up this style */
private AttributeSet a;
}
/** Patterns registered with this SnytaxPane */
private Vector patterns;
/** the cursor to use to indicate a lengthy operation is going on */
private final Cursor waitCursor = Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR);
}