How to use

IProjectionPosition

in

org.eclipse.jface.text.source.projection

private boolean isCaptionLine(Position position, IDocument document, int line) {
  if (position.getOffset() > -1 && position.getLength() > -1) {
    try {
      int captionOffset;
      if (position instanceof IProjectionPosition)
        captionOffset= ((IProjectionPosition) position).computeCaptionOffset(document);
      else
        captionOffset= 0;
      int startLine= document.getLineOfOffset(position.getOffset() + captionOffset);
      return line == startLine;
    } catch (BadLocationException x) {
    }
  }
  return false;
}

/**
 * Computes the regions that must be collapsed when the given position is
 * the position of an expanded projection annotation.
 *
 * @param position the position
 * @return the ranges that must be collapsed, or <code>null</code> if
 *         there are none
 * @since 3.1
 */
IRegion[] computeCollapsedRegions(Position position) {
  try {
    IDocument document= getDocument();
    if (document == null)
      return null;
    if (position instanceof IProjectionPosition) {
      IProjectionPosition projPosition= (IProjectionPosition) position;
      return projPosition.computeProjectionRegions(document);
    }
    int line= document.getLineOfOffset(position.getOffset());
    int offset= document.getLineOffset(line + 1);
    int length= position.getLength() - (offset - position.getOffset());
    if (length > 0)
      return new IRegion[] {new Region(offset, length)};
    return null;
  } catch (BadLocationException x) {
    return null;
  }
}

/**
 * Computes the regions that must be collapsed when the given position is
 * the position of an expanded projection annotation.
 *
 * @param position the position
 * @return the ranges that must be collapsed, or <code>null</code> if
 *         there are none
 * @since 3.1
 */
IRegion[] computeCollapsedRegions(Position position) {
  try {
    IDocument document= getDocument();
    if (document == null)
      return null;
    if (position instanceof IProjectionPosition) {
      IProjectionPosition projPosition= (IProjectionPosition) position;
      return projPosition.computeProjectionRegions(document);
    }
    int line= document.getLineOfOffset(position.getOffset());
    int offset= document.getLineOffset(line + 1);
    int length= position.getLength() - (offset - position.getOffset());
    if (length > 0)
      return new IRegion[] {new Region(offset, length)};
    return null;
  } catch (BadLocationException x) {
    return null;
  }
}

private boolean isCaptionLine(Position position, IDocument document, int line) {
  if (position.getOffset() > -1 && position.getLength() > -1) {
    try {
      int captionOffset;
      if (position instanceof IProjectionPosition)
        captionOffset= ((IProjectionPosition) position).computeCaptionOffset(document);
      else
        captionOffset= 0;
      int startLine= document.getLineOfOffset(position.getOffset() + captionOffset);
      return line == startLine;
    } catch (BadLocationException x) {
    }
  }
  return false;
}

/**
 * Computes the collapsed region anchor for the given position. Assuming
 * that the position is the position of an expanded projection annotation,
 * the anchor is the region that is still visible after the projection
 * annotation has been collapsed.
 *
 * @param position the position
 * @return the collapsed region anchor
 */
public Position computeCollapsedRegionAnchor(Position position) {
  try {
    IDocument document= getDocument();
    if (document == null)
      return null;
    int captionOffset= position.getOffset();
    if (position instanceof IProjectionPosition)
      captionOffset+= ((IProjectionPosition) position).computeCaptionOffset(document);
    IRegion lineInfo= document.getLineInformationOfOffset(captionOffset);
    return new Position(lineInfo.getOffset() + lineInfo.getLength(), 0);
  } catch (BadLocationException x) {
  }
  return null;
}

/**
 * Computes the collapsed region anchor for the given position. Assuming
 * that the position is the position of an expanded projection annotation,
 * the anchor is the region that is still visible after the projection
 * annotation has been collapsed.
 *
 * @param position the position
 * @return the collapsed region anchor
 */
public Position computeCollapsedRegionAnchor(Position position) {
  try {
    IDocument document= getDocument();
    if (document == null)
      return null;
    int captionOffset= position.getOffset();
    if (position instanceof IProjectionPosition)
      captionOffset+= ((IProjectionPosition) position).computeCaptionOffset(document);
    IRegion lineInfo= document.getLineInformationOfOffset(captionOffset);
    return new Position(lineInfo.getOffset() + lineInfo.getLength(), 0);
  } catch (BadLocationException x) {
  }
  return null;
}

int captionOffset;
if (position instanceof IProjectionPosition)
  captionOffset= ((IProjectionPosition) position).computeCaptionOffset(document);
else
  captionOffset= 0;

int captionOffset;
if (position instanceof IProjectionPosition)
  captionOffset= ((IProjectionPosition) position).computeCaptionOffset(document);
else
  captionOffset= 0;