code: public synchronized void locking(Context ctxt, ILexLocation location)
  	{
  		// Enter a locking state - called by thread
  		waitUntilState(RunState.LOCKING, RunState.RUNNING, ctxt, location);
  	}
docs: /*
  (non-Javadoc)
  @see org.overture.vdmj.scheduler.ISchedulableThread#locking(org.overture.vdmj.runtime.Context,
  org.overture.vdmj.lex.ILexLocation)