[Chapter 18] Applet
Author: John Zukowski
Date: Thu Jul 31 14:59:24 1997

#

| Chapter 18 java.applet Reference |

# Applet

## Name

Applet

##

## Description

The `Applet` class provides the framework for delivering Java programs within web pages.

## Class Definition

    public class java.applet.Applet
        extends java.awt.Panel {
      // Constructors
      public Applet();
      // Instance Methods
      public void destroy();
      public AppletContext getAppletContext();
      public String getAppletInfo();
      public AudioClip getAudioClip (URL url);
      public AudioClip getAudioClip (URL url, String filename);
      public URL getCodeBase();
      public URL getDocumentBase();
      public Image getImage (URL url);
      public Image getImage (URL url, String filename);
      public Locale getLocale();
      public String getParameter (String name);
      public String[][] getParameterInfo();
      public void init();
      public boolean isActive();
      public void play (URL url);
      public void play (URL url, String filename);
      public void resize (int width, int height);
      public void resize (Dimension dim);
      public final void setStub (AppletStub stub);
      public void showStatus (String message);
      public void start();
      public void stop();
    }

## Constructors

### Applet

#### public Applet()

Description

  Constructs an `Applet` object.

## Instance Methods

### destroy

#### public void destroy()

Description

  Called when the browser determines that it doesn't need to keep the applet around anymore.

### getAppletContext

#### public AppletContext getAppletContext()

Returns

  The current `AppletContext` of the applet.

### getAppletInfo

#### public String getAppletInfo()

Returns

  A short information string about the applet to be shown to the user.

### getAudioClip

#### public AudioClip getAudioClip (URL url)

Parameters

  url

    `URL` of an audio file.

Returns

  Object that implements the `AudioClip` interface for playing audio files.

Description

  Fetches an audio file to play with the `AudioClip` interface.

#### public AudioClip getAudioClip (URL url , String filename)

Parameters

  url

    Base `URL` of an audio file.

  filename

    Specific file, relative to `url`, that contains an audio file.

Returns

  Object that implements `AudioClip` interface for playing audio file.

Description

  Fetches an audio file to play with the `AudioClip` interface.

### getCodeBase

#### public URL getCodeBase()

Returns

  The complete `URL` of the .class file that contains the applet.

### getDocumentBase

#### public URL getDocumentBase()

Returns

  The complete `URL` of the .html file that loaded the applet.

### getImage

#### public Image getImage (URL url)

Parameters

  url

    `URL` of an image file.

Returns

  `Image` to be displayed.

Description

  Initiates the image loading process for the file located at the specified location.

#### public Image getImage (URL url, String filename)

Parameters

  url

    Base `URL` of an image file.

  filename

    Specific file, relative to `url`, that contains an image file.

Returns

  Image to be displayed.

Description

  Initiates the image loading process for the file located at the specified location.

### getLocale

#### public Locale getLocale()

Returns

  `Applet`'s locale.

Overrides

  `Component.get` `Locale``()`

Description

  Used for internationalization support.

### getParameter

#### public String getParameter (String name)

Parameters

  name

    Name of parameter to get.

Returns

  The value associated with the given parameter in the HTML file, or `null`.

Description

  Allows you to get parameters from within the `<APPLET>` tag of the .html file that loaded the applet.

### getParameterInfo

#### public String[][] getParameterInfo()

Returns

  Overridden to provide a series of three-string arrays that describes the parameters this applet reads.

### init

#### public void init()

Description

  Called by the system when the applet is first loaded.

### isActive

#### public boolean isActive()

Returns

  `true` if the applet is active, `false` otherwise.

### play

#### public void play (URL url)

Parameters

  url

    `URL` of an audio file .

Description

  Plays an audio file once.

#### public void play (URL url, String filename)

Parameters

  url

    Base `URL` of an audio file .

  filename

    Specific file, relative to `url`, that contains an audio file.

Description

  Plays an audio file once.

### resize

#### public void resize(int width, int height)

Parameters

  width

    New width for the `Applet`.

  height

    New height for the `Applet`.

Description

  Changes the size of the applet.

#### public void resize (Dimension dim)

Parameters

  dim

    New dimensions for the applet.

Description

  Changes the size of the applet.

### setStub

#### public final void setStub (AppletStub stub)

Parameters

  stub

    Platform specific stubfor environment.

Description

  Called by the system to setup `AppletStub`.

### showStatus

#### public void showStatus (String message)

Parameters

  message

    Message to display to user.

Description

  Displays a message on the status line of the browser.

### start

#### public void start()

Description

  Called by the system every time the applet is displayed.

### stop

#### public void stop()

Description

  Called by the system when it wants the applet to stop execution; typically, every time the user leaves the page that includes the applet.

## See Also

`AppletContext`, `AppletStub`, `AudioClip`, `Container`, `Dimension`, `Image`, `Locale`, `Panel`, `String`, `URL`

Package diagrams |  | AppletContext