Michael F Day

US Patent:

57615110, Jun 2, 1998

Filed:

Jan 28, 1994

Appl. No.:

8/187972

Inventors:

Jonathan J. Gibbons - Mountain View CA
Michael J. Day - Mountain View CA
Theodore C. Goldstein - Palo Alto CA
Michael J. Jordan - Palo Alto CA

Assignee:

Sun Microsystems, Inc. - Palo Alto CA

International Classification:

G06F 945

US Classification:

395705

Abstract:

The present invention provides a system and process for making use of pre-existing data-structures which represent a computer program, in a way which has the advantages of shortening the time and cost required to create a new version of the computer program. The pre-existing data-structure is modified to produce a shadow data-structure which contains only shadows of those elements or nodes of the pre-existing data-structure required to perform the tasks of the new version of the computer program. The present invention includes processes to make the data-structure of the original program shadowable; processes to use data from the original program compilation process in compiling the new version of the program, including processes to create a shadow data-structure; and processes to use the new version of the computer program along with the shadow data-structure to create the desired execution. This new version of the computer program is typically a tool for checking or observing the original program's execution in some manner. Moreover, the system and processes disclosed provide mechanisms for a software manufacturer to create type-safe versions of a connected collection of objects which are dynamically extensible.