ip-ch05-example-10-2.java

class GraphicEditor {
    ...
    public void mouseDown() {
        tool.mouseDown();
    }
    ...
}

class RectangleTool {
    private GraphicEditor editor;

    public RectangleTool(GraphicEditor editor) {
        this.editor = editor;
    }

    public void mouseDown() {
        editor.add(new RectangleFigure());
    }
    ...
}