US 6,651,248 B1Granted

Method and apparatus for efficient interface method dispatch

AssigneeInternational Business Machines Corporation

InventorBowen Alpern

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Abstract

The interface method invocation mechanism of the present invention includes an interface method table (IMT) for a given class of objects. The IMT comprises a table of entries each corresponding to a set S of interface methods that are implemented by objects of the given class. The entries of the IMT are used to support invocation of interface methods. More specifically, processing of a method invocation statement involves either I) loading the pointer to the implementation of the interface method from an entry of the IMT and passing control to this implementation; or II) loading the pointer to a conflict resolution routine pointed by an IMT entry and passing control to this conflict resolution routine. The conflict resolution routine pointed to by the IMT entry identifies at execution time to the location of the particular interface method of the two or more interface methods that are associated with the given IMT entry that corresponds to the method invocation statement being processed, and pass control to this particular interface method.

Claims7

Dependent claims

A computer implemented method for invoking interface methods in an object oriented program, said computer implemented method comprising the steps of:

providing a table of entries each corresponding to a set S of interface methods implemented by the program, wherein, for at least one given entry, the set S corresponding to the given entry belongs to one of a first type and a second type, the first type including a single interface virtual method implemented by the program and the second type including a plurality of interface methods implemented by the program, wherein:
in the event that the set S corresponding to the given entry belongs to the first type, the given entry stores a pointer to the implementation of the single virtual method in the set S corresponding to the given entry;
and
in the event that the set S corresponding to the given entry belongs to the second type, the given entry stores a pointer to the implementation of a conflict resolution routine that operates at execution time to selectively identify one of the plurality of interface methods in the set S corresponding to the given entry, and transfer control from the conflict resolution routine to the implementation of the identified one interface method.

1 more element

Dependencies are inferred from the claim text.