DETERMINING AN EXTENSION TO USE TO PROCESS AN INPUT OBJECT TO A CALL IN A PROGRAM

• US 20080155555A1
• Filed: 12/21/2006
• Published: 06/26/2008
• Est. Priority Date: 12/21/2006
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: KWONG, Michael Yiupun
• Granted Patent: US 8,307,379 B2
• Time in Patent Office: Days
• US Class Current: 719/315
• CPC Class Codes: G06F 8/20 Software design
• CPC Class Codes: G06F 8/24 Object-oriented
• CPC Class Codes: G06F 9/44526 Plug-ins; Add-ons
• CPC Class Codes: G06F 9/449 Object-oriented method invocation or resolution

Abstract

Provided are a method, system, and article of manufacture for determining an extension to use to process an input object to a call in a program. An association of parameter definitions is indicated with extensions, where each extension comprises a program capable of being selected to process at least one input object as part of an operation. A call is received for an extension point including at least one input object to determine one extension to use to process the at least one object, wherein requirements are defined for the extension point. A determination is made of a set of candidate extensions capable of processing the at least one input object based on a first criteria determining extensions whose parameter definitions are capable of satisfying the requirements defined for the extension point. A selection is made from the set of candidate extensions of one extension to use to process the at least one object using a second criteria.

Claims

1. A method, comprising:

indicating an association of parameter definitions with extensions, where each extension comprises a program capable of being selected to process at least one input object as part of an operation;

receiving a call for an extension point including at least one input object to determine one extension to use to process the at least one object, wherein requirements are defined for the extension point;

determining a set of candidate extensions capable of processing the at least one input object based on a first criteria determining extensions whose parameter definitions are capable of satisfying the requirements defined for the extension point; and

selecting from the set of candidate extensions one extension to use to process the at least one object using a second criteria.

2. The method of claim 1, wherein the call includes multiple objects, wherein the extension point requirements indicate a number of expected input object parameters and at least one attribute of the input objects, and wherein the determined set of candidate extensions have parameter definitions indicating that they are capable of processing the expected input object parameters and input objects having the at least one attribute indicated in the extension point requirements.

3. The method of claim 1, wherein the second criteria selects at least one extension having parameter definitions that satisfy attributes of the at least one input object with a greatest degree of specificity.

4. The method of claim 1, wherein the attributes of the at least one object are associated with a hierarchy of the attributes, and wherein using the second criteria comprises using the hierarchy to select from the set of candidate extensions the extension to use to process the at least one input object.

5. The method of claim 4, wherein using the hierarchy of attributes of the at least one object, comprises:

determining one extension associated whose parameter definitions satisfy the attributes of the at least one object at a lower level in the hierarchy than the parameter definitions of other extensions.

6. The method of claim 5, wherein a different priority is associated with each extension, and wherein using the hierarchy of parameters of the at least one object further comprises:

determining at least two extensions having parameter definitions that satisfy the attributes of the at least one object at a lower level in the hierarchy than the parameter definitions of other extensions, wherein a determination cannot be made of which of the determined extensions satisfy attributes at a lowest level in the hierarchy; and

selecting one of the determined at least two extensions that has a highest priority.

7. The method of claim 5, wherein determining the extension comprises:

comparing the parameter definitions of two extensions from the set of candidate extensions to determine a winner extension of the two extensions whose parameter definitions satisfy the attributes of the at least one object at a lower level in the hierarchy than the parameter definitions of a non-winning extension;

comparing the parameter definitions of the winner extension and one extension from a set of candidate extensions not yet compared to determine a next winner extension in response to there being at least one extension in the set of candidate extensions not yet compared; and

setting the determined extension to use to a most recently determined winner extension in response to there not being one extension in the set not yet considered.

8. The method of claim 1, further comprising:

providing a first class interface having methods to indicate the association of the parameters with extensions; and

providing a second class interface having a first method to determine the set of candidate extensions based on the first criteria and a second method to determine the set of candidate extensions based on the second criteria.

9. The method of claim 1, wherein the extensions are provided by third party developers to be invoked at the extension point in program code.

10. The method of claim 1, wherein the at least one object comprises a source object indicating objects in a file system from which to copy files and a target object indicating target objects to which the objects in the file system are written, and wherein the parameters associated with the source and target objects indicate an operating system and object type, wherein selecting one candidate extension comprises selecting one extension associated with parameters satisfying at least one of the operating system and object type parameters associated with the source and target objects.

11. A system, comprising:

a processor; and

code executed by the processor to cause the processor to perform operations, the operations comprising;

indicating an association of parameter definitions with extensions, where each extension comprises a program capable of being selected to process at least one input object as part of an operation;

receiving a call for an extension point including at least one input object to determine one extension to use to process the at least one object, wherein requirements are defined for the extension point;

determining a set of candidate extensions capable of processing the at least one input object based on a first criteria determining extensions whose parameter definitions are capable of satisfying the requirements defined for the extension point; and

selecting from the set of candidate extensions one extension to use to process the at least one object using a second criteria.

12. The system of claim 11, wherein the call includes multiple objects, wherein the extension point requirements indicate a number of expected input object parameters and at least one attribute of the input objects, and wherein the determined set of candidate extensions have parameter definitions indicating that they are capable of processing the expected input object parameters and input objects having the at least one attribute indicated in the extension point requirements.

13. The system of claim 11, wherein the second criteria selects at least one extension having parameter definitions that satisfy attributes of the at least one input object with a greatest degree of specificity.

14. The system of claim 11, wherein the attributes of the at least one object are associated with a hierarchy of the attributes, and wherein using the second criteria comprises using the hierarchy to select from the set of candidate extensions the extension to use to process the at least one input object.

15. The system of claim 14, wherein using the hierarchy of attributes of the at least one object, comprises:

determining one extension associated whose parameter definitions satisfy the attributes of the at least one object at a lower level in the hierarchy than the parameter definitions of other extensions.

16. The system of claim 15, wherein a different priority is associated with each extension, and wherein using the hierarchy of parameters of the at least one object further comprises:

determining at least two extensions having parameter definitions that satisfy the attributes of the at least one object at a lower level in the hierarchy than the parameter definitions of other extensions, wherein a determination cannot be made of which of the determined extensions satisfy attributes at a lowest level in the hierarchy; and

selecting one of the determined at least two extensions that has a highest priority.

17. The system of claim 15, wherein determining the extension comprises:

comparing the parameter definitions of two extensions from the set of candidate extensions to determine a winner extension of the two extensions whose parameter definitions satisfy the attributes of the at least one object at a lower level in the hierarchy than the parameter definitions of a non-winning extension;

comparing the parameter definitions of the winner extension and one extension from a set of candidate extensions not yet compared to determine a next winner extension in response to there being at least one extension in the set of candidate extensions not yet compared; and

setting the determined extension to use to a most recently determined winner extension in response to there not being one extension in the set not yet considered.

18. The system of claim 11, wherein the operations further comprise:

providing a first class interface having methods to indicate the association of the parameters with extensions; and

providing a second class interface having a first method to determine the set of candidate extensions based on the first criteria and a second method to determine the set of candidate extensions based on the second criteria.

19. The system of claim 11, wherein the extensions are provided by third party developers to be invoked at the extension point in program code.

20. The system of claim 11, wherein the at least one object comprises a source object indicating objects in a file system from which to copy files and a target object indicating target objects to which the objects in the file system are written, and wherein the parameters associated with the source and target objects indicate an operating system and object type, wherein selecting one candidate extension comprises selecting one extension associated with parameters satisfying at least one of the operating system and object type parameters associated with the source and target objects.

21. An article of manufacture implementing code, wherein the code is capable of causing operations to be performed, the operations comprising:

indicating an association of parameter definitions with extensions, where each extension comprises a program capable of being selected to process at least one input object as part of an operation;

receiving a call for an extension point including at least one input object to determine one extension to use to process the at least one object, wherein requirements are defined for the extension point;

determining a set of candidate extensions capable of processing the at least one input object based on a first criteria determining extensions whose parameter definitions are capable of satisfying the requirements defined for the extension point; and

selecting from the set of candidate extensions one extension to use to process the at least one object using a second criteria.

22. The article of manufacture of claim 21, wherein the call includes multiple objects, wherein the extension point requirements indicate a number of expected input object parameters and at least one attribute of the input objects, and wherein the determined set of candidate extensions have parameter definitions indicating that they are capable of processing the expected input object parameters and input objects having the at least one attribute indicated in the extension point requirements.

23. The article of manufacture of claim 21, wherein the second criteria selects at least one extension having parameter definitions that satisfy attributes of the at least one input object with a greatest degree of specificity.

24. The article of manufacture of claim 21, wherein the attributes of the at least one object are associated with a hierarchy of the attributes, and wherein using the second criteria comprises using the hierarchy to select from the set of candidate extensions the extension to use to process the at least one input object.

25. The article of manufacture of claim 24, wherein using the hierarchy of attributes of the at least one object, comprises:

determining one extension associated whose parameter definitions satisfy the attributes of the at least one object at a lower level in the hierarchy than the parameter definitions of other extensions.

26. The article of manufacture of claim 25, wherein a different priority is associated with each extension, and wherein using the hierarchy of parameters of the at least one object further comprises:

determining at least two extensions having parameter definitions that satisfy the attributes of the at least one object at a lower level in the hierarchy than the parameter definitions of other extensions, wherein a determination cannot be made of which of the determined extensions satisfy attributes at a lowest level in the hierarchy; and

selecting one of the determined at least two extensions that has a highest priority.

27. The article of manufacture of claim 25, wherein determining the extension comprises:

comparing the parameter definitions of two extensions from the set of candidate extensions to determine a winner extension of the two extensions whose parameter definitions satisfy the attributes of the at least one object at a lower level in the hierarchy than the parameter definitions of a non-winning extension;

comparing the parameter definitions of the winner extension and one extension from a set of candidate extensions not yet compared to determine a next winner extension in response to there being at least one extension in the set of candidate extensions not yet compared; and

setting the determined extension to use to a most recently determined winner extension in response to there not being one extension in the set not yet considered.

28. The article of manufacture of claim 21, further comprising:

providing a first class interface having methods to indicate the association of the parameters with extensions; and

providing a second class interface having a first method to determine the set of candidate extensions based on the first criteria and a second method to determine the set of candidate extensions based on the second criteria.

29. The article of manufacture of claim 21, wherein the extensions are provided by third party developers to be invoked at the extension point in program code.

30. The article of manufacture of claim 21, wherein the at least one object comprises a source object indicating objects in a file system from which to copy files and a target object indicating target objects to which the objects in the file system are written, and wherein the parameters associated with the source and target objects indicate an operating system and object type, wherein selecting one candidate extension comprises selecting one extension associated with parameters satisfying at least one of the operating system and object type parameters associated with the source and target objects.