How can i show/hide the tab asterisk at runtime?

In Settings/Editor(IDE Settings)/Editor Tabs: I Checked "Mark modified tabs with asterisk"

I have :

public class MyEditor implements FileEditor, FileEditorManagerListener { ....

@Override
  public boolean isModified() {
         return isDirty;
  }

public void changeIsModifiedState(boolean  newDirtyState) {
     if (isDirty != newDirtyState) {
          isDirty = newDirtyState;
          ..... ...... //code to neede to fire the change
     }

}

I want to use the second method to show or hide the "asterisk" whenever i need to.
How can this be done? Or any other suggestion. Thank you!