bluej.extensions
Class Extension

java.lang.Object
  bluej.extensions.Extension

public abstract class Extension
extends java.lang.Object

Defines the interface between BlueJ and an extension. All extensions must extend this class. A concrete extension class must also have a no-arguments constructor.

Author:

Clive Miller, University of Kent at Canterbury, 2002, Damiano Bolla, University of Kent at Canterbury, 2003,2004

Field Summary

int	VERSION_MAJOR The major version number of the Extension API.
int	VERSION_MINOR The minor version number of the Extension API.

Constructor Summary

Extension()

Method Summary

java.lang.String	getDescription() Should return a description of the extension's function.
abstract java.lang.String	getName() Should return a name for this extension.
java.net.URL	getURL() Should return a URL where more information about the extension is available.
abstract java.lang.String	getVersion() Should return the version of the extension.
abstract boolean	isCompatible() Determine whether this extension is compatible with a particular version of the extensions API.
abstract void	startup(BlueJ bluej) Called when the extension can start its activity.
void	terminate() Called when the extension should tidy up and terminate.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

VERSION_MAJOR

public int VERSION_MAJOR

The major version number of the Extension API. Provided so that extensions can check for compatibility.

VERSION_MINOR

public int VERSION_MINOR

The minor version number of the Extension API. Provided so that extensions can check for compatibility.

Constructor Detail

Extension

public Extension()

Method Detail

isCompatible

public abstract boolean isCompatible()

Determine whether this extension is compatible with a particular version of the extensions API. This method is called before the startup() method. An extension can use VERSION_MAJOR and VERSION_MINOR as an aid to determine whether it is compatible with the current BlueJ release.

startup

public abstract void startup(BlueJ bluej)

Called when the extension can start its activity. This is not called on a separate thread. Extensions should return as quick as possible from this method after creating their own thread if necessary.

Parameters:

bluej - The starting point for interactions with BlueJ

terminate

public void terminate()

Called when the extension should tidy up and terminate. When BlueJ decides that this extension is no longer needed it will call this method before removing it from the system. Note that an extension may be reloaded after having been terminated.

Any attempt by an extension to call methods on its BlueJ object after this method has been called will result in an (unchecked) ExtensionUnloadedException being thrown by the BlueJ object.

getName

public abstract java.lang.String getName()

Should return a name for this extension. This will be displayed in the Help->Installed Extensions dialog.

Please limit the name to between 5 and 10 characters, and bear in mind the possibility of name conflicts.

getVersion

public abstract java.lang.String getVersion()

Should return the version of the extension. Please limit the string to between 5 and 10 characters. This will be displayed in the Help->Installed Extensions dialog

getDescription

public java.lang.String getDescription()

Should return a description of the extension's function. It should be a brief statement of the extension's purpose. This will be displayed in the Help->Installed Extensions dialog

getURL

public java.net.URL getURL()

Should return a URL where more information about the extension is available. This will be displayed in the Help->Installed Extensions dialog. If no information is available then null may be returned.

Ideally the information provided at the URL includes a complete manual, possible upgrades and configuration details.