CanInstallSelf

DefaultReceiverForSelf FinishInstallingSelf InstallFallback InstallSelf InstallSelfIntoWithFallback

Attributes

Class CanInstallSelf defines no new attributes.

Fields

 
Define Class CanInstallSelf;
    mixes in with Object;

    operation DefaultReceiverForSelf(): Object;
        // Used by the standard InstallSelf method to find a receiver
        // to install into.  
        // Override often.  Many times, this is the only method you need
        // to override to make your object able to install itself.

    operation InstallSelf();
        // Installs itself into the system.  Since no arguments are
        // passed, the installable object must know where and how 
        // it should install itself.  Thus, control panel buttons 
        // automatically know to install themselves into the control 
        // panel, and doors automatically know to install themselves 
        // into the hallway.
        //
        // The default method calls InstallSelfIntoWithFallback using the
        // DefaultReceiverForSelf as the location and self as the
        // fallbackHandler.  
        //
        // You often want to override InstallSelfIntoWithFallback or
        // FinishInstallingSelf instead of overriding InstallSelf.  If you
        // override InstallSelf directly, it will be impossible for a caller
        // to override your choice of receiver, or to specify a different
        // fallback.  Depending on your situation, this may or may not be
        // relevant.

    operation InstallSelfIntoWithFallback(receiver: Object; fallbackHandler: CanInstallSelf);
        // * If the receiver exists, this method installs the object into
        // the receiver using the InstallInto call, and then calls 
        // FinishInstallingSelf on self.
        // * If the receiver does not exist, this method calls InstallSelf
        // on the fallbackHandler unless fallbackHandler is self, in which
        // case it calls InstallFallback(self) instead.  If fallbackHandler
        // is nilObject, no fallback is installed.
        // Sometimes override to perform installation in a different way.

    operation FinishInstallingSelf();
        // Perform an action after installation.  This method is only
        // called if the installation was successful.
        // The default method does nothing.
        // Often override to do something interesting after the
        // object has been installed.

    operation InstallFallback();
        // Perform an action if the installation fails.  This method is
        // only called if InstallSelfIntoWithFallback is called with self as
        // the fallbackHandler.  
        // The default method does nothing.
        // Often override to do something interesting after the
        // installation fails.
end class;