The Java TM Tutorial

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Trail: JavaBeans
Lesson: Using the BeanBox

## Starting and Using the BeanBox

> This section gives you a brief, introductory look at the BeanBox and it's basic operation. The `beans/beanbox` directory contains Windows (`run.bat`) and Unix (`run.sh`) scripts that start the BeanBox. You can use these commands to start the BeanBox, or use a `make` utility:

> Platform | Command
> --- | ---
> Unix | `gmake run`
> Windows | `nmake run`

> See the BDK files `beans/doc/makefiles.html` and `beans/doc/gnu.txt` for information about getting copies of `gnumake` and `nmake`.

> When started, the BeanBox displays three windows: The ToolBox, the BeanBox window, and the Properties sheet.

> This figure has been reduced to fit on the page.
> Click the image to view it at its natural size.

> Here are brief descriptions of each window.

> - The ToolBox contains the Beans available for use by the BeanBox. To work on a Bean, you choose it from the ToolBox and drop it on the BeanBox window.

> - The BeanBox window is the area where you visually wire Beans together, defining how Beans appear, and interact with other Beans. The BeanBox window is itself an instance of a BeanBox Bean. The above screenshot shows the BeanBox window with a `Juggler` Bean instance dropped in it. Later you'll see how to wire the `Juggler` to two button Beans that start and stop him juggling.

>   You select among Beans in the BeanBox window simply by clicking on the Bean. The selected Bean will have a hatced border, as the `Juggler` Bean does in the above screenshot. Which Bean is selected has significance for the Properties sheet.

> - The Properties sheet displays the properties for the Bean currently selected within the BeanBox window. In the above screenshot, the Properties sheet displays the `Juggler` Bean's properties. If you drop another Bean in the BeanBox window, the properties sheet will display that Bean's properties.

### Adding a Bean to the ToolBox

> When the BeanBox is started, it automatically loads the ToolBox with all the Beans it finds within the JAR files contained in the `beans/jars` directory. Move your JAR files into that directory to have them automatically loaded at BeanBox startup. You can load Beans from JAR files located elsewhere by using the File|LoadJar... BeanBox menu item.

### Dropping a Bean on the BeanBox

> Clicking on a Bean name within the ToolBox chooses that Bean for placement within the BeanBox. To drop a `JellyBean` instance onto the BeanBox

> 1. Click on the word `JellyBean` in the ToolBox. The cursor will change to a crosshair when flying over the BeanBox windows.
> 2. Click within the BeanBox. The `JellyBean` instance will appear, and will be selected.

> Note the change in the Properties sheet when you put the `JellyBean` in the BeanBox. Before you placed the `JellyBean` in the BeanBox, the BeanBox's properties were displayed. After placing the `JellyBean` in the BeanBox, the `JellyBean` properties are displayed. If you missed the change, click within the BeanBox, away from the `JellyBean`. This will select the BeanBox rather than the `JellyBean`. The Properties sheet will then display the BeanBox's properties.

> After dropping a `JellyBean` instance on the BeanBox, the Properties sheet displays the `JellyBean` properties: `color`, `foreground`, `priceInCents`, `background`, and `font`.

### Editing Bean Properties

> The Properties sheet displays each property's name and its current value. Values are displayed in an editable text field (strings and numbers), a choice menu (booleans), or as painted values (colors and fonts). Each property has an associated property editor. Clicking on a property within the Properties sheet activates the property's editor. Properties displayed in text fields or choice menus are edited within the Properties sheet. Because editing their values requires a more sophisticated user interface, `Color` and `Font` property types use a custom property editor. When you click on a color or font property a separate panel will pop up to do the editing. Try clicking on each of the `JellyBean` properties.

### Saving and Restoring Beans

> You can save the state of a Bean that your are customizing, and restore the Bean and its saved state at a later time. The BeanBox uses Java Object Serialization to save and restore Beans and their state. The following steps demonstrate how to save and restore a Bean:

> 1. Drop a `JellyBean` on the BeanBox.
> 2. Change the `color` property to anything you want.
> 3. Select the File|Save menu item. A file browser will pop up; use it to save the Bean to a file.
> 4. Select the File|Clear menu item.
> 5. Select the File|Load menu item. The file browser will again pop up; use it to retrieve the serialized Bean. The `JellyBean` will be the color you chose.

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