write a program that contains two frames, one with a column of text fields containing numbers, and another that draws a bar graph showing the values of the numbers. When the user edits one of the numbers, the graph should be redrawn. Use the observer pattern. Store the data in a model. Attach the graph view as a listener. When a number is updated, the number view should update the model, and the model should tell the graph view that a change has occurred. As a result, the graph view should repaint itself