MultiLineComment swt

 

//Send questions, comments, bug reports, etc. to the authors:

//Rob Warner ([e-mail])
//Robert Harris ([e-mail])

import java.util.ArrayList;
import java.util.LinkedList;

import org.eclipse.swt.*;
import org.eclipse.swt.custom.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.widgets.Display;

/**
* This program demonstrates multiline comments. It uses MultiLineCommentListener
* to do the syntax coloring
*/
public class MultiLineComment {
/**
 * Runs the application
 */
public void run() {
  Display display = new Display();
  Shell shell = new Shell(display);
  shell.setText("Multiline Comments");
  createContents(shell);
  shell.open();
  while (!shell.isDisposed()) {
    if (!display.readAndDispatch()) {
      display.sleep();
    }
  }
  display.dispose();
}

/**
 * Creates the main window contents
 *
 * @param shell the main window
 */
private void createContents(Shell shell) {
  shell.setLayout(new FillLayout());
  final StyledText styledText = new StyledText(shell, SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL);

  // Add the line style listener
  final MultiLineCommentListener lineStyleListener = new MultiLineCommentListener();
  styledText.addLineStyleListener(lineStyleListener);

  // Add the modification listener
  styledText.addExtendedModifyListener(new ExtendedModifyListener() {
    public void modifyText(ExtendedModifyEvent event) {
      // Recalculate the comments
      lineStyleListener.refreshMultilineComments(styledText.getText());

      // Redraw the text
      styledText.redraw();
    }
  });
}

/**
 * The application entry point
 *
 * @param args the command line arguments
 */
public static void main(String[] args) {
  new MultiLineComment().run();
}
}
//Send questions, comments, bug reports, etc. to the authors:

//Rob Warner ([e-mail])
//Robert Harris ([e-mail])
/**
* This class supports multiline comments. It turns comments green.
*/
class MultiLineCommentListener implements LineStyleListener {
// Markers for multiline comments
private static final String COMMENT_START = "/*";
private static final String COMMENT_END = "*/";

// Color for comments
private static final Color COMMENT_COLOR = Display.getCurrent().getSystemColor(
    SWT.COLOR_DARK_GREEN);

// Offsets for all multiline comments
LinkedList commentOffsets;

/**
 * MultilineCommentListener constructor
 */
public MultiLineCommentListener() {
  commentOffsets = new LinkedList();
}

/**
 * Refreshes the offsets for all multiline comments in the parent StyledText.
 * The parent StyledText should call this whenever its text is modified. Note
 * that this code doesn't ignore comment markers inside strings.
 *
 * @param text the text from the StyledText
 */
public void refreshMultilineComments(String text) {
  // Clear any stored offsets
  commentOffsets.clear();

  // Go through all the instances of COMMENT_START
  for (int pos = text.indexOf(COMMENT_START); pos > -1; pos = text.indexOf(
      COMMENT_START, pos)) {
    // offsets[0] holds the COMMENT_START offset
    // and COMMENT_END holds the ending offset
    int[] offsets = new int[2];
    offsets[0] = pos;

    // Find the corresponding end comment.
    pos = text.indexOf(COMMENT_END, pos);

    // If no corresponding end comment, use the end of the text
    offsets[1] = pos == -1 ? text.length() - 1 : pos + COMMENT_END.length() - 1;
    pos = offsets[1];

    // Add the offsets to the collection
    commentOffsets.add(offsets);
  }
}

/**
 * Called by StyledText to get the styles for a line
 *
 * @param event the event
 */
public void lineGetStyle(LineStyleEvent event) {
  // Create a collection to hold the StyleRanges
  ArrayList styles = new ArrayList();

  // Store the length for convenience
  int length = event.lineText.length();

  for (int i = 0, n = commentOffsets.size(); i < n; i++) {
    int[] offsets = (int[]) commentOffsets.get(i);

    // If starting offset is past current line--quit
    if (offsets[0] > event.lineOffset + length) break;

    // Check if we're inside a multiline comment
    if (offsets[0] <= event.lineOffset + length
        && offsets[1] >= event.lineOffset) {
      // Calculate starting offset for StyleRange
      int start = Math.max(offsets[0], event.lineOffset);

      // Calculate length for style range
      int len = Math.min(offsets[1], event.lineOffset + length) - start + 1;

      // Add the style range
      styles.add(new StyleRange(start, len, COMMENT_COLOR, null));
    }
  }

  // Copy all the ranges into the event
  event.styles = (StyleRange[]) styles.toArray(new StyleRange[0]);
}
}