# Modeling Buttons: States and Events

## Finite State Machine

Below is a Finite state machine diagram a simple button application. We want to implement this dynamic Menu with these interactive Button behaviors using Processing. This button system is referred to as a radio-type button group.

![](/files/-M0-KfqMHqYZEFZAOXmB)

The diagram above shows that we have a menu of 3 buttons, where only 1 button can be active at any time. The arcs indicate events, which correspond to the user clicking a button, the arcs also indicate tasks that must be implemented in our code to insure the system demonstrates the desired behavior. The events can cause the menu-system to change state.

```java
States - Which Button is Active:   Button1 , Button2, Button3

Events - User Interactions:   click1, click2, click3
```

The arrows in the diagram represent events: The events cause the button to change state. To implement a button-group in our program code, we'll need to create a variable that we can use to remember which button is currently active.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://kdoore.gitbook.io/cs1335/object-oriented-programming/modelingstates_and_events_md.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.