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Design pattern:
	Mediator

Description:
	"Defines an object that encapsulates how a set of objects interact.
	Mediator promotes loose coupling by keeping objects from referring
	to each other explicitly, and it lets you vary their interaction
	independently."

This pattern can be used with both classes and prototypes.

Print Logtalk, Prolog backend, and kernel versions (if running as a notebook):

```logtalk
%versions
```

Start by loading the design pattern sample implementation:

```logtalk
logtalk_load(design_patterns('behavioral/mediator/loader')).
```

First, click the "book" button:

```logtalk
book_button::click.
```

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Next, click the "view" button:

```logtalk
view_button::click.
```

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Finally, click the "search" button:

```logtalk
search_button::click.
```

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