code: public String getStringValue() throws ControlException{
  		String v;
  		
  		if(type!=V4L4JConstants.CTRL_TYPE_STRING)
  			throw new UnsupportedMethod("This control is not a string control");
  		
  		state.get();
  		
  		try {v = doGetStringValue(v4l4jObject, id);}
  		finally{state.put(); }
  			
  		return v;
  	}
docs: This method retrieves the current string value of this control.
  Some controls may be write-only and getting
  their value does not make sense. Invoking this method on this kind of
  controls will trigger a ControlException.
  @return the current value of this control
  @throws ControlException if the value cannot be retrieved
  @throws UnsupportedMethod if this control
  is not of type {@link V4L4JConstants#CTRL_TYPE_STRING}.
  @throws StateException if this control has been released and must not be used anymore.