| 摘要 |
In an object oriented computer system, one or more run-time extensible items are defined that may be dynamically reconfigured as required to support different interfaces at run-time. The behavior associated with these interfaces is supported by one or more extensions owned by the extensible item. Each extension class has a corresponding method table that is shared among instances of the extension class and that correlates the methods defined on the extension class to method node objects that carry out the method. A method repository is a static object that is created at run-time to correlate extensions to their corresponding method tables. When a client invokes an invokeMethod( ) method on an extensible item, specifying the name of the method to be invoked, the extensible item cycles through its extensions, from newest to oldest, looking for an extension that supports the named method. Each extension examines the method repository to see if the method repository contains a method table corresponding to the extension class. If not, a method table corresponding to the extension class is created and placed in the method repository. When an extension is found that supports the named method, a method node that corresponds to the named method is returned. The method node then invokes the named method on the extension.
|
