# 5
Hi' i found this code. but i think this is to complex for me. can anyone explain to me? cos i just need to match the input from user type with the keywords.
package gui;
import java.awt.Color;
import java.io.FileInputStream;
import java.io.ObjectInputStream;
import java.util.HashMap;
import javax.swing.event.DocumentEvent;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultEditorKit;
import javax.swing.text.DefaultStyledDocument;
import javax.swing.text.Element;
import javax.swing.text.MutableAttributeSet;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;
public class SyntaxParser extends DefaultStyledDocument
{
private DefaultStyledDocument doc;
private Element rootElement;
private boolean multiLineComment;
private MutableAttributeSet normal;
private MutableAttributeSet keyword;
private MutableAttributeSet comment;
private MutableAttributeSet quote;
private HashMap keywords = null;
public SyntaxParser() {
doc = this;
rootElement = doc.getDefaultRootElement();
putProperty(DefaultEditorKit.EndOfLineStringProperty, "\n");
normal = new SimpleAttributeSet();
StyleConstants.setForeground(normal, Color.black);
comment = new SimpleAttributeSet();
Color green = new Color(0, 200, 0);
StyleConstants.setForeground(comment, green);
//StyleConstants.setItalic(comment, true);
keyword = new SimpleAttributeSet();
Color blue = new Color(0, 0, 255);
StyleConstants.setForeground(keyword, blue);
//StyleConstants.setBold(keyword, true);
quote = new SimpleAttributeSet();
Color red = new Color(255, 0, 0);
StyleConstants.setForeground(quote, red);
//Object dummyObject = new Object();
try
{
FileInputStream fis =
new FileInputStream("Keywords.txt");
ObjectInputStream ois =
new ObjectInputStream(fis);
keywords = (HashMap)ois.readObject();
ois.close();
}
catch (Exception e)
{
}
/*
* Override to apply syntax highlighting after the document has been updated
*/
public void insertString(int offset, String str, AttributeSet a) throws BadLocationException
{
if (str.equals("{"))
str = addMatchingBrace(offset);
super.insertString(offset, str, a);
processChangedLines(offset, str.length());
}
/*
* Override to apply syntax highlighting after the document has been updated
*/
public void remove(int offset, int length) throws BadLocationException
{
super.remove(offset, length);
processChangedLines(offset, 0);
}
/*
* Determine how many lines have been changed,
* then apply highlighting to each line
*/
private void processChangedLines(int offset, int length) throws BadLocationException
{
String content = doc.getText(0, doc.getLength());
// The lines affected by the latest document update
int startLine = rootElement.getElementIndex(offset);
int endLine = rootElement.getElementIndex(offset + length);
// Make sure all comment lines prior to the start line are commented
// and determine if the start line is still in a multi line comment
setMultiLineComment(commentLinesBefore(content, startLine));
// Do the actual highlighting
for (int i = startLine; i <= endLine; i++)
applyHighlighting(content, i);
// Resolve highlighting to the next end multi line delimiter
if (isMultiLineComment())
commentLinesAfter(content, endLine);
else
highlightLinesAfter(content, endLine);
}
/*
* Highlight lines when a multi line comment is still 'open'
* (ie. matching end delimiter has not yet been encountered)
*/
private boolean commentLinesBefore(String content, int line)
{
int offset = rootElement.getElement(line).getStartOffset();
// Start of comment not found, nothing to do
int startDelimiter = lastIndexOf(content, getStartDelimiter(),
offset - 2);
if (startDelimiter < 0)
return false;
// Matching start/end of comment found, nothing to do
int endDelimiter = indexOf(content, getEndDelimiter(), startDelimiter);
if (endDelimiter < offset & endDelimiter != -1)
return false;
// End of comment not found, highlight the lines
doc.setCharacterAttributes(startDelimiter, offset - startDelimiter + 1,comment, false);
return true;
}
/*
* Highlight comment lines to matching end delimiter
*/
private void commentLinesAfter(String content, int line)
{
int offset = rootElement.getElement(line).getEndOffset();
// End of comment not found, nothing to do
int endDelimiter = indexOf(content, getEndDelimiter(), offset);
if (endDelimiter < 0)
return;
// Matching start/end of comment found, comment the lines
int startDelimiter = lastIndexOf(content, getStartDelimiter(),
endDelimiter);
if (startDelimiter < 0 || startDelimiter <= offset)
{
doc.setCharacterAttributes(offset, endDelimiter - offset + 1,
comment, false);
}
}
/*
* Highlight lines to start or end delimiter
*/
private void highlightLinesAfter(String content, int line) throws BadLocationException
{
int offset = rootElement.getElement(line).getEndOffset();
// Start/End delimiter not found, nothing to do
int startDelimiter = indexOf(content, getStartDelimiter(), offset);
int endDelimiter = indexOf(content, getEndDelimiter(), offset);
if (startDelimiter < 0)
startDelimiter = content.length();
if (endDelimiter < 0)
endDelimiter = content.length();
int delimiter = Math.min(startDelimiter, endDelimiter);
if (delimiter < offset)
return;
// Start/End delimiter found, reapply highlighting
int endLine = rootElement.getElementIndex(delimiter);
for (int i = line + 1; i < endLine; i++)
{
Element branch = rootElement.getElement(i);
Element leaf = doc.getCharacterElement(branch.getStartOffset());
AttributeSet as = leaf.getAttributes();
if (as.isEqual(comment))
applyHighlighting(content, i);
}
}
/*
* Parse the line to determine the appropriate highlighting
*/
private void applyHighlighting(String content, int line)throws BadLocationException
{
int startOffset = rootElement.getElement(line).getStartOffset();
int endOffset = rootElement.getElement(line).getEndOffset() - 1;
int lineLength = endOffset - startOffset;
int contentLength = content.length();
if (endOffset >= contentLength)
endOffset = contentLength - 1;
// check for multi line comments
// (always set the comment attribute for the entire line)
if (endingMultiLineComment(content, startOffset, endOffset) || isMultiLineComment() || startingMultiLineComment(content, startOffset, endOffset))
{
doc.setCharacterAttributes(startOffset,
endOffset - startOffset + 1, comment, false);
return;
}
// set normal attributes for the line
doc.setCharacterAttributes(startOffset, lineLength, normal, true);
// check for single line comment
int index = content.indexOf(getSingleLineDelimiter(), startOffset);
if ((index > -1) && (index < endOffset))
{
doc.setCharacterAttributes(index, endOffset - index + 1, comment,
false);
endOffset = index - 1;
}
// check for tokens
checkForTokens(content, startOffset, endOffset);
}
/*
* Does this line contain the start delimiter
*/
private boolean startingMultiLineComment(String content, int startOffset,
int endOffset) throws BadLocationException
{
int index = indexOf(content, getStartDelimiter(), startOffset);
if ((index < 0) || (index > endOffset))
return false;
else
{
setMultiLineComment(true);
return true;
}
}
/*
* Does this line contain the end delimiter
*/
private boolean endingMultiLineComment(String content, int startOffset,int endOffset) throws BadLocationException
{
int index = indexOf(content, getEndDelimiter(), startOffset);
if ((index < 0) || (index > endOffset))
return false;
else
{
setMultiLineComment(false);
return true;
}
}
/*
* We have found a start delimiter
* and are still searching for the end delimiter
*/
private boolean isMultiLineComment()
{
return multiLineComment;
}
private void setMultiLineComment(boolean value)
{
multiLineComment = value;
}
/*
* Parse the line for tokens to highlight
*/
private void checkForTokens(String content, int startOffset, int endOffset)
{
while (startOffset <= endOffset)
{
// skip the delimiters to find the start of a new token
while (isDelimiter(content.substring(startOffset, startOffset + 1)))
{
if (startOffset < endOffset)
startOffset++;
else
return;
}
// Extract and process the entire token
if (isQuoteDelimiter(content
.substring(startOffset, startOffset + 1)))
startOffset = getQuoteToken(content, startOffset, endOffset);
else
startOffset = getOtherToken(content, startOffset, endOffset);
}
}
/*
* Parse the line to get the quotes and highlight it
*/
private int getQuoteToken(String content, int startOffset, int endOffset)
{
String quoteDelimiter = content.substring(startOffset, startOffset + 1);
String escapeString = getEscapeString(quoteDelimiter);
int index;
int endOfQuote = startOffset;
// skip over the escape quotes in this quote
index = content.indexOf(escapeString, endOfQuote + 1);
while ((index > -1) && (index < endOffset))
{
endOfQuote = index + 1;
index = content.indexOf(escapeString, endOfQuote);
}
// now find the matching delimiter
index = content.indexOf(quoteDelimiter, endOfQuote + 1);
if ((index < 0) || (index > endOffset))
endOfQuote = endOffset;
else
endOfQuote = index;
doc.setCharacterAttributes(startOffset, endOfQuote - startOffset + 1,
quote, false);
return endOfQuote + 1;
}
private int getOtherToken(String content, int startOffset, int endOffset)
{
int endOfToken = startOffset + 1;
while (endOfToken <= endOffset)
{
if (isDelimiter(content.substring(endOfToken, endOfToken + 1)))
break;
endOfToken++;
}
String token = content.substring(startOffset, endOfToken);
if (isKeyword(token))
doc.setCharacterAttributes(startOffset, endOfToken - startOffset,
keyword, false);
return endOfToken + 1;
}
/*
* This updates the colored text and prepares for undo event
*/
protected void fireInsertUpdate(DocumentEvent evt)
{
super.fireInsertUpdate(evt);
try
{
processChangedLines(evt.getOffset(), evt.getLength());
}
catch (BadLocationException ex)
{
System.out.println("" + ex);
}
}
/*
* This updates the colored text and does the undo operation
*/
protected void fireRemoveUpdate(DocumentEvent evt)
{
super.fireRemoveUpdate(evt);
try
{
processChangedLines(evt.getOffset(), evt.getLength());
}
catch (BadLocationException ex)
{
System.out.println("" + ex);
}
}
/*
* Assume the needle will the found at the start/end of the line
*/
private int indexOf(String content, String needle, int offset)
{
int index;
while ((index = content.indexOf(needle, offset)) != -1)
{
String text = getLine(content, index).trim();
if (text.startsWith(needle) || text.endsWith(needle))
break;
else
offset = index + 1;
}
return index;
}
/*
* Assume the needle will the found at the start/end of the line
*/
private int lastIndexOf(String content, String needle, int offset)
{
int index;
while ((index = content.lastIndexOf(needle, offset)) != -1)
{
String text = getLine(content, index).trim();
if (text.startsWith(needle) || text.endsWith(needle))
break;
else
offset = index - 1;
}
return index;
}
private String getLine(String content, int offset)
{
int line = rootElement.getElementIndex(offset);
Element lineElement = rootElement.getElement(line);
int start = lineElement.getStartOffset();
int end = lineElement.getEndOffset();
return content.substring(start, end - 1);
}
/*
* Override for other languages
*/
protected boolean isDelimiter(String character)
{
String operands = ";:{}()[]+-/%<=>!&|^~*";
if (Character.isWhitespace(character.charAt(0))|| operands.indexOf(character) != -1)
return true;
else
return false;
}
/*
* Override for other languages
*/
protected boolean isQuoteDelimiter(String character)
{
String quoteDelimiters = "\"'";
if (quoteDelimiters.indexOf(character) < 0)
return false;
else
return true;
}
/*
* Override for other languages
*/
protected boolean isKeyword(String token)
{
Object o = keywords.get(token);
return o == null ? false : true;
}
/*
* Override for other languages
*/
protected String getStartDelimiter()
{
return "/*";
}
/*
* Override for other languages
*/
protected String getEndDelimiter()
{
return "*/";
}
/*
* Override for other languages
*/
protected String getSingleLineDelimiter()
{
return "//";
}
/*
* Override for other languages
*/
protected String getEscapeString(String quoteDelimiter)
{
return "\\" + quoteDelimiter;
}
/*
* Overide bracket matching for other languages
*/
protected String addMatchingBrace(int offset) throws BadLocationException
{
StringBuffer whiteSpace = new StringBuffer();
int line = rootElement.getElementIndex(offset);
int i = rootElement.getElement(line).getStartOffset();
while (true) {
String temp = doc.getText(i, 1);
if (temp.equals(" ") || temp.equals("\t")) {
whiteSpace.append(temp);
i++;
} else
break;
}
return "{\n" + whiteSpace.toString() + whiteSpace.toString() + "\n"
+ whiteSpace.toString() + "}";
}
}
This code. it really works. but i don't understand about it. does this code override the insertString() method from Document? is there any better explanation?
Thanks....
