How to use

selectionChanged

method

in

org.eclipse.jface.text.TextViewer

@Override
public void widgetDefaultSelected(SelectionEvent event) {
  selectionChanged(event.x, event.y - event.x);
}
@Override

  @Override
  public void widgetSelected(SelectionEvent event) {
    selectionChanged(event.x, event.y - event.x);
  }
});

@Override
public void widgetDefaultSelected(SelectionEvent event) {
  selectionChanged(event.x, event.y - event.x);
}
@Override

  @Override
  public void widgetSelected(SelectionEvent event) {
    selectionChanged(event.x, event.y - event.x);
  }
});

@Override
public void setSelectedRange(int selectionOffset, int selectionLength) {
  if (!redraws()) {
    if (fViewerState != null)
      fViewerState.updateSelection(selectionOffset, selectionLength);
    return;
  }
  if (fTextWidget == null)
    return;
  IRegion widgetSelection= modelRange2ClosestWidgetRange(new Region(selectionOffset, selectionLength));
  if (widgetSelection != null) {
    int[] selectionRange= new int[] { widgetSelection.getOffset(), widgetSelection.getLength() };
    validateSelectionRange(selectionRange);
    if (selectionRange[0] >= 0) {
      fTextWidget.setSelectionRange(selectionRange[0], selectionRange[1]);
      selectionChanged(selectionRange[0], selectionRange[1]);
    }
  }
}

@Override
public void setSelectedRange(int selectionOffset, int selectionLength) {
  if (!redraws()) {
    if (fViewerState != null)
      fViewerState.updateSelection(selectionOffset, selectionLength);
    return;
  }
  if (fTextWidget == null)
    return;
  IRegion widgetSelection= modelRange2ClosestWidgetRange(new Region(selectionOffset, selectionLength));
  if (widgetSelection != null) {
    int[] selectionRange= new int[] { widgetSelection.getOffset(), widgetSelection.getLength() };
    validateSelectionRange(selectionRange);
    if (selectionRange[0] >= 0) {
      fTextWidget.setSelectionRange(selectionRange[0], selectionRange[1]);
      selectionChanged(selectionRange[0], selectionRange[1]);
    }
  }
}

  fTextWidget.setSelectionRange(widgetPos, length);
  internalRevealRange(widgetPos, widgetPos + length);
  selectionChanged(widgetPos, length);
} else {
  setSelectedRange(widgetOffset2ModelOffset(widgetPos), length);

  fTextWidget.setSelectionRange(widgetPos, length);
  internalRevealRange(widgetPos, widgetPos + length);
  selectionChanged(widgetPos, length);
} else {
  setSelectedRange(widgetOffset2ModelOffset(widgetPos), length);

  fTextWidget.setSelectionRange(widgetPos, length);
  internalRevealRange(widgetPos, widgetPos + length);
  selectionChanged(widgetPos, length);
} else {
  setSelectedRange(modelPos, length);

  fTextWidget.setSelectionRange(widgetPos, length);
  internalRevealRange(widgetPos, widgetPos + length);
  selectionChanged(widgetPos, length);
} else {
  setSelectedRange(modelPos, length);

if (widgetSelection[0] >= 0) {
  fTextWidget.setBlockSelectionBounds(Geometry.createRectangle(startLocation, Geometry.subtract(endLocation, startLocation)));
  selectionChanged(startOffset, widgetLength);

if (widgetSelection[0] >= 0) {
  fTextWidget.setBlockSelectionBounds(Geometry.createRectangle(startLocation, Geometry.subtract(endLocation, startLocation)));
  selectionChanged(startOffset, widgetLength);