Process and device for deciding class hierarchical relationship of object oriented language and process and device for determining method utilizing the same

• US 5,313,633 A
• Filed: 05/29/1990
• Issued: 05/17/1994
• Est. Priority Date: 05/31/1989
• Status: Expired due to Fees

• Current Assignee: Hitachi Seibu Soft Ware Company Limited
• Original Assignee: Hitachi, Ltd., Hitachi Seibu Soft Ware Company Limited
• Inventors: Yoshimura, Kiyozumi, Tomita, Hiroshi
• Primary Examiner(s): Shaw, Gareth D.
• Assistant Examiner(s): KATBAB, ABDOLLAH
• Application Number:
  US07/529,955
• Time in Patent Office: 1,449 Days
• Field of Search: 395/700, 364/DIG. 1, 364/280, 364/280.4
• US Class Current: 1/1
• CPC Class Codes: G06F 9/449 Object-oriented method invocation or resolution
• CPC Class Codes: Y10S 707/99931 Database or file accessing

Abstract

A process and a device for deciding class hierarchical relationship of an object oriented language which, in decision of the relationship of class inheritance of an object oriented language having a hierarchical relationship of classes, performs coding processing for affixing the codes each having a predetermined relation to each of those classes and decides the relationship of inheritance in a hierarchy of two optional classes with said series of codes affixed to said two optional classes having said hierarchical relationship.

Claims

1. A computer implemented process of operating an object oriented language having a plurality of classes in a class hierarchical relationship in a single inheritance and using a message passing to activate a method, comprising:

affixing codes to each of said plurality of classes wherein the codes have a predetermined relation to each other as a basis for the class hierarchical relationship; and

deciding at a time of said message passing, the class hierarchical relationship between the plurality of classes by identifying the predetermined relation between said codes affixed to said classes having said class hierarchical relationship, wherein said affixing occurs prior to said deciding.

2. The process of operating an object oriented language according to claim 1, wherein the affixing comprises using numerical characters as said affixed codes, and wherein the numerical characters, with a specific class as a reference and comprising the codes of classes in a sub hierarchy thereof, are numerical values that increase consecutively from a first numerical character affixed to said specific class to a predetermined range.

3. The process of deciding class hierarchical relationship of an object oriented language according to claim 2, wherein, in said decision of relationship of inheritance, when the code of a certain specific class is a numerical character within said predetermined range of the class in a sub hierarchy of a class different from said specific class, said specific class is decided to be a class in the sub hierarchy of said different class.

4. The process of operating an object oriented language according to claim 1, wherein said affixing comprises traversing all classes in the class hierarchy having a tree structure from a root class of the tree structure by a depth-first and left-to-right strategy and affixing the code of each class when the class is first traversed.

5. The process of operating an object oriented language according to claim 1, wherein said affixing comprises a first traversing of all classes in the class hierarchy having a tree structure from a root class of the tree structure and a second traversing by upward strategy, and the code of each class is affixed during the second traversing.

6. The process of operating an object oriented language according to claim 1, wherein the affixing codes comprises a processing in which codes of varied length are used as the codes and affixing a certain code including a code pattern of a certain class for the codes of all the classes in a sub hierarchy of said certain class.

7. The process of operating an object oriented language according to claim 6, wherein said deciding of the relationship of inheritance comprises deciding, when the certain code of the certain class includes a code of a different class, that said certain class is a class in a sub hierarchy of said different class.

8. A computer implemented process of operating an object oriented language comprising classes which determines a method to be activated by message passing described in an object oriented language from information of a receiver which is a passing destination in the message passing and a message selector includes in the message passing, comprising:

affixing codes each having a predetermined relation to each of said classes of the passing destination of the message passing;

performing extraction processing of candidate methods to be activated based on information of said message selector and on said codes affixed, and prior to the message passing deciding a relationship of inheritance in a hierarchy of two optional classes from said codes affixed to said two optional classes; and

determining the method to be activated based on said relationship of inheritance of said receiver among candidate methods extracted by said extraction processing, wherein said determining is performed when the message passing is performed.

9. The process of operating an object oriented language according to claim 8, wherein said extraction processing of the candidate methods includes extracting all the candidate methods having a same message selector as the message selector passed in message passing irrespective of said information of said receiver.

10. The process of operating an object oriented language according to claim 9, wherein, after said extraction processing of the candidate methods having the same message selector, includes performing said method determining only when a number of extracted candidate methods is less than a predetermined number.

11. The process of operating an object oriented language according to claim 10, wherein said extraction processing of candidate method includes performing said extraction processing prior to each execution of said message passing.

12. The process of operating an object oriented language according to claim 9, wherein, in a method final determination processing, said determining includes comparing each class holding the candidate methods extracted by said candidate extraction processing with the class to which said receiver belongs, and selecting one class by a result of said comparing, and activating the candidate method held by said selected one class.

13. The process of operating an object oriented language according to claim 12, wherein said comparing includes deciding a class hierarchical relationship between each class holding the candidate methods extracted by said extraction processing and the class to which said receiver belongs, and said selecting includes selecting a second class which is a super class of the one class to which said receiver belongs.

16. The process of operating an object oriented language according to claim 9, wherein:

providing said object oriented language with a class hierarchy including multiple inheritance;

converting said class hierarchy including multiple inheritance into a class hierarchy of single inheritance having an equivalent relationship with respect to methods inherited; and

extracting the methods to be activated with respect to said converted class hierarchy of single inheritance.

17. The process of operating an object oriented language according to claim 16, wherein said converting into a single inheritance is made, for those classes that inherit the methods from a plurality of super classes, into a class hierarchy of single inheritance only from the super class having the highest priority in the relationship of inheritance of said plurality of super classes which is designated in advance.

14. A computer-implemented process of operating an object oriented language in which a method to be activated by message passing described in the object oriented language is determined from information of a receiver which is a passing destination of said message passing and a message selector includes in said message passing, comprising extracting those methods that are possible to activated by said message passing before execution of said message passing, and determining the method to be activated among those methods that are extracted by said extraction processing at execution time of said message passing.

15. The process of operating an object oriented language according to claim 14, further including, when the method to be activated by said message passing can be decided unequivocally before execution of said message passing, determining the method to be activated before execution of relevant message passing.