ParenMatcherpublic class ParenMatcher extends JTextPane implements Runnable
| Fields Summary |
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| public static Color[] | matchColor | | public static Color | badColor | | private AttributeSet[] | matchAttrSet | | private AttributeSet | badAttrSet |
| Constructors Summary |
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public ParenMatcher()
// create an array of AttributeSets from the array of Colors
StyleContext sc = StyleContext.getDefaultStyleContext();
badAttrSet = sc.addAttribute(SimpleAttributeSet.EMPTY,
StyleConstants.Foreground, badColor);
matchAttrSet = new AttributeSet[matchColor.length];
for (int j=0; j < matchColor.length; j+=1)
matchAttrSet[j] = sc.addAttribute(SimpleAttributeSet.EMPTY,
StyleConstants.Foreground, matchColor[j]);
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| Methods Summary |
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| public static void | main(java.lang.String[] args)
JFrame frame = new JFrame("ParenMatcher");
final ParenMatcher matcher = new ParenMatcher();
matcher.setText("int fact(int n) {\n"
+" if (n <= 1) return 1;\n"
+" return(n * fact(n-1));\n"
+"}\n");
frame.getContentPane().add(new JScrollPane(matcher), BorderLayout.CENTER);
JButton matchButton = new JButton("match parens");
matchButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) { matcher.run(); }
});
frame.getContentPane().add(matchButton, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(200, 150);
frame.setVisible(true);
| | public static boolean | matches(char left, char right)
if (left == '(") return (right == ')");
if (left == '[") return (right == ']");
if (left == '{") return (right == '}");
return false;
| | public void | replaceSelection(java.lang.String content)
getInputAttributes().removeAttribute(StyleConstants.Foreground);
super.replaceSelection(content);
| | public void | run()
StyledDocument doc = getStyledDocument();
String text = "";
int len = doc.getLength();
try {
text = doc.getText(0, len);
} catch (BadLocationException ble) { }
java.util.Stack stack = new java.util.Stack();
for (int j=0; j < text.length(); j+=1) {
char ch = text.charAt(j);
if (ch == '(" || ch == '[" || ch == '{") {
int depth = stack.size();
stack.push(""+ch+j); // push a String containg the char and the offset
AttributeSet aset = matchAttrSet[depth % matchAttrSet.length];
doc.setCharacterAttributes(j, 1, aset, false);
}
if (ch == ')" || ch == ']" || ch == '}") {
String peek = stack.empty() ? "." : (String)stack.peek();
if (matches(peek.charAt(0), ch)) { // does it match?
stack.pop();
int depth = stack.size();
AttributeSet aset = matchAttrSet[depth % matchAttrSet.length];
doc.setCharacterAttributes(j, 1, aset, false);
}
else { // mismatch
doc.setCharacterAttributes(j, 1, badAttrSet, false);
}
}
}
while (! stack.empty()) { // anything left in the stack is a mismatch
String pop = (String)stack.pop();
int offset = Integer.parseInt(pop.substring(1));
doc.setCharacterAttributes(offset, 1, badAttrSet, false);
}
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