/**
   * This method is called AFTER the content has been inserted into the document and the element
   * structure has been updated.
   *
   * <p>The syntax-highlighting updates need to be done here (as opposed to an override of <code>
   * postRemoveUpdate</code>) as this method is called in response to undo/redo events, whereas
   * <code>postRemoveUpdate</code> is not.
   *
   * <p>Now that the text is actually inserted into the content and element structure, we can update
   * our token elements and "last tokens on lines" structure.
   *
   * @param chng The change that occurred.
   * @see #removeUpdate
   */
  protected void fireRemoveUpdate(DocumentEvent chng) {

    Element lineMap = getDefaultRootElement();
    int numLines = lineMap.getElementCount();

    DocumentEvent.ElementChange change = chng.getChange(lineMap);
    Element[] removed = change == null ? null : change.getChildrenRemoved();

    // If entire lines were removed...
    if (removed != null && removed.length > 0) {

      int line = change.getIndex(); // First line entirely removed.
      int previousLine = line - 1; // Line before that.
      int previousTokenType =
          (previousLine > -1 ? lastTokensOnLines.get(previousLine) : Token.NULL);

      Element[] added = change.getChildrenAdded();
      int numAdded = added == null ? 0 : added.length;

      // Remove the cached last-token values for the removed lines.
      int endBefore = line + removed.length - numAdded;
      // System.err.println("... removing lines: " + line + " - " + (endBefore-1));
      // System.err.println("... added: " + numAdded + ", removed: " + removed.length);

      lastTokensOnLines.removeRange(
          line, endBefore); // Removing values for lines [line-(endBefore-1)].
      // System.err.println("--------- lastTokensOnLines.size() == " + lastTokensOnLines.getSize());

      // Update last tokens for lines below until they've stopped changing.
      updateLastTokensBelow(line, numLines, previousTokenType);

    } // End of if (removed!=null && removed.size()>0).

    // Otherwise, text was removed from just one line...
    else {

      int line = lineMap.getElementIndex(chng.getOffset());
      if (line >= lastTokensOnLines.getSize())
        return; // If we're editing the last line in a document...

      int previousLine = line - 1;
      int previousTokenType =
          (previousLine > -1 ? lastTokensOnLines.get(previousLine) : Token.NULL);
      // System.err.println("previousTokenType for line : " + previousLine + " is " +
      // previousTokenType);
      // Update last tokens for lines below until they've stopped changing.
      updateLastTokensBelow(line, numLines, previousTokenType);
    }

    // Let all of our listeners know about the removal.
    super.fireRemoveUpdate(chng);
  }
  /**
   * Alerts all listeners to this document of an insertion. This is overridden so we can update our
   * syntax highlighting stuff.
   *
   * <p>The syntax highlighting stuff has to be here instead of in <code>insertUpdate</code> because
   * <code>insertUpdate</code> is not called by the undo/redo actions, but this method is.
   *
   * @param e The change.
   */
  protected void fireInsertUpdate(DocumentEvent e) {

    /*
     * Now that the text is actually inserted into the content and
     * element structure, we can update our token elements and "last
     * tokens on lines" structure.
     */

    Element lineMap = getDefaultRootElement();
    DocumentEvent.ElementChange change = e.getChange(lineMap);
    Element[] added = change == null ? null : change.getChildrenAdded();

    int numLines = lineMap.getElementCount();
    int line = lineMap.getElementIndex(e.getOffset());
    int previousLine = line - 1;
    int previousTokenType = (previousLine > -1 ? lastTokensOnLines.get(previousLine) : Token.NULL);

    // If entire lines were added...
    if (added != null && added.length > 0) {

      Element[] removed = change.getChildrenRemoved();
      int numRemoved = removed != null ? removed.length : 0;

      int endBefore = line + added.length - numRemoved;
      // System.err.println("... adding lines: " + line + " - " + (endBefore-1));
      // System.err.println("... ... added: " + added.length + ", removed:" + numRemoved);
      for (int i = line; i < endBefore; i++) {

        setSharedSegment(i); // Loads line i's text into s.

        int tokenType = tokenMaker.getLastTokenTypeOnLine(s, previousTokenType);
        lastTokensOnLines.add(i, tokenType);
        // System.err.println("--------- lastTokensOnLines.size() == " +
        // lastTokensOnLines.getSize());

        previousTokenType = tokenType;
      } // End of for (int i=line; i<endBefore; i++).

      // Update last tokens for lines below until they stop changing.
      updateLastTokensBelow(endBefore, numLines, previousTokenType);

    } // End of if (added!=null && added.length>0).

    // Otherwise, text was inserted on a single line...
    else {

      // Update last tokens for lines below until they stop changing.
      updateLastTokensBelow(line, numLines, previousTokenType);
    } // End of else.

    // Let all listeners know about the insertion.
    super.fireInsertUpdate(e);
  }
  /**
   * Loops through the last-tokens-on-lines array from a specified point onward, updating last-token
   * values until they stop changing. This should be called when lines are updated/inserted/removed,
   * as doing so may cause lines below to change color.
   *
   * @param line The first line to check for a change in last-token value.
   * @param numLines The number of lines in the document.
   * @param previousTokenType The last-token value of the line just before <code>line</code>.
   * @return The last line that needs repainting.
   */
  private int updateLastTokensBelow(int line, int numLines, int previousTokenType) {

    int firstLine = line;

    // Loop through all lines past our starting point.  Update even the last
    // line's info, even though there aren't any lines after it that depend
    // on it changing for them to be changed, as its state may be used
    // elsewhere in the library.
    int end = numLines;
    // System.err.println("--- end==" + end + " (numLines==" + numLines + ")");
    while (line < end) {

      setSharedSegment(line); // Sets s's text to that of line 'line' in the document.

      int oldTokenType = lastTokensOnLines.get(line);
      int newTokenType = tokenMaker.getLastTokenTypeOnLine(s, previousTokenType);
      // System.err.println("---------------- line " + line + "; oldTokenType==" + oldTokenType + ",
      // newTokenType==" + newTokenType + ", s=='" + s + "'");

      // If this line's end-token value didn't change, stop here.  Note
      // that we're saying this line needs repainting; this is because
      // the beginning of this line did indeed change color, but the
      // end didn't.
      if (oldTokenType == newTokenType) {
        // System.err.println("... ... ... repainting lines " + firstLine + "-" + line);
        fireChangedUpdate(
            new DefaultDocumentEvent(firstLine, line, DocumentEvent.EventType.CHANGE));
        return line;
      }

      // If the line's end-token value did change, update it and
      // keep going.
      // NOTE: "setUnsafe" is okay here as the bounds checking was
      // already done in lastTokensOnLines.get(line) above.
      lastTokensOnLines.setUnsafe(line, newTokenType);
      previousTokenType = newTokenType;
      line++;
    } // End of while (line<numLines).

    // If any lines had their token types changed, fire a changed update
    // for them.  The view will repaint the area covered by the lines.
    // FIXME:  We currently cheat and send the line range that needs to be
    // repainted as the "offset and length" of the change, since this is
    // what the view needs.  We really should send the actual offset and
    // length.
    if (line > firstLine) {
      // System.err.println("... ... ... repainting lines " + firstLine + "-" + line);
      fireChangedUpdate(new DefaultDocumentEvent(firstLine, line, DocumentEvent.EventType.CHANGE));
    }

    return line;
  }
 /**
  * Returns the token type of the last token on the given line.
  *
  * @param line The line to inspect.
  * @return The token type of the last token on the specified line. If the line is invalid, an
  *     exception is thrown.
  */
 public int getLastTokenTypeOnLine(int line) {
   return lastTokensOnLines.get(line);
 }