Decomposing a generic class into layers

• US 9,910,680 B2
• Filed: 03/17/2015
• Issued: 03/06/2018
• Est. Priority Date: 04/22/2014
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Goetz, Brian, Rose, John R.
• Primary Examiner(s): VU, TUAN A
• Application Number:
  US14/660,604
• Publication Number:
  US 20150301825A1
• Time in Patent Office: 1,085 Days
• CPC Class Codes: G06F 8/24 Object-oriented
• CPC Class Codes: G06F 8/315 Object-oriented languages
• CPC Class Codes: G06F 8/41 Compilation
• CPC Class Codes: G06F 8/437 Type checking
• CPC Class Codes: G06F 8/443 Optimisation
• CPC Class Codes: G06F 8/447 Target code generation
• CPC Class Codes: G06F 8/70 Software maintenance or management
• CPC Class Codes: G06F 8/71 Version control security arrangements therefor G06F21/57; Configuration management
• CPC Class Codes: G06F 8/76 Adapting program code to run in a different environment; Porting
• CPC Class Codes: G06F 9/44521 Dynamic linking or loading; Link editing at or after load time, e.g. Java class loading
• CPC Class Codes: G06F 9/4488 Object-oriented
• CPC Class Codes: G06F 9/449 Object-oriented method invocation or resolution
• CPC Class Codes: G06F 9/4492 Inheritance
• CPC Class Codes: G06F 9/4498 Finite state machines
• CPC Class Codes: G06F 9/45516 Runtime code conversion or optimisation

Abstract

The domain of genericity of an existing generic class may be expanded to include not just reference types, but also primitive and value types even though some members of the existing class do not support the expanded genericity. A subdivided version of the class may be created that includes a generic layer including abstract versions of class members and a reference-specific layer that including non-abstract versions of class members that are abstract in the generic layer. The subdivided version of the class may also include information that indicates to which layer a class member belongs. Problematic methods (e.g., methods that have built-in assumptions regarding the domain of genericity) may be moved into the second, reference-specific, layer, thereby retaining compatibility with classes that currently instantiate or reference those methods, while still allowing use within the expanded domain of genericity.

Claims

1. A non-transitory, computer-readable storage medium storing program instructions that when executed on a computing device cause the computing device to perform:

expanding a domain of genericity of an existing generic class comprising a plurality of class members, wherein one or more of the plurality of class members do not support at least part of the expanded domain of genericity, wherein the domain of genericity comprises a range of types over which the generic class is eligible for specialization, wherein for the expanded domain of genericity the range of types includes one or more reference types and one or more non-reference types, wherein the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity do not support specialization for the one or more non-reference types;

wherein said expanding comprises;

creating a subdivided version of the class that supports the expanded domain of genericity and preserves compatibility with the existing generic class, wherein creating the subdivided version of the class comprises;

including, in the subdivided version of the class, one or more indicators that identify one or more of the plurality of class members that support the expanded domain of genericity as part of a first layer of the subdivided version of the class, and the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity as part of a second layer of the subdivided version of the class.

2. The non-transitory, computer-readable storage medium of claim 1,

wherein the first layer is a generic layer including abstract versions of the one or more of the plurality of class members that support the expanded domain of genericity;

and

wherein the second layer is a reference-specific layer including a non-abstract version of at least one of the one or more of the plurality of class members for which abstract versions are included in the generic layer.

3. The non-transitory, computer-readable storage medium of claim 2, wherein the program instruction further cause the computing device to perform loading a fully generic version of the subdivided class, wherein said loading comprises:

including in the fully generic version of the subdivided class the one or more of the plurality of class members for which abstract versions are included in the generic layer; and

not including in the fully generic version of the subdivided class the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity.

4. The non-transitory, computer-readable storage medium of claim 2, wherein the program instruction further cause the computing device to perform loading a reference-specific version of the subdivided class, wherein said loading comprises:

not including in the reference-specific version of the subdivided class the one or more of the plurality of class members for which abstract versions are included in the generic layer; and

including in the reference-specific version of the subdivided class the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity.

5. The non-transitory, computer-readable storage medium of claim 2, wherein the program instructions further cause the computing device to perform specializing the subdivided class for a non-reference type parameterization, wherein said specializing comprises:

creating a specialized version of the subdivided class that includes the one or more of the plurality of class members for which abstract version are included in the generic layer; and

not including in the specialized version of the subdivided class the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity.

6. The non-transitory, computer-readable storage medium of claim 1, wherein the plurality of class members includes one or more of:

a method, a field, a constructor, or a nested type.

7. A method implemented with a computing system having at least one processor coupled with memory-stored executable instructions which, when executed by the processor, cause the processor to perform the method, comprising:

expanding, by a compiler or a platform independent, object oriented runtime environment implemented on one or more computing devices, a domain of genericity of an existing generic class comprising a plurality of class members, wherein one or more of the plurality of class members do not support at least part of the expanded domain of genericity, wherein the domain of genericity comprises a range of types over which the generic class is eligible for specialization, wherein for the expanded domain of genericity the range of types includes one or more reference types and one or more non-reference types, wherein the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity do not support specialization for the one or more non-reference types;

wherein said expanding comprises;

creating, by the compiler or the platform independent, object oriented runtime environment, a subdivided version of the class that supports the expanded domain of genericity and preserves compatibility with the existing generic class, wherein creating the subdivided version of the class comprises;

including, by the compiler or the platform independent, object oriented runtime environment, in the subdivided version of the class, one or more indicators that identify one or more of the plurality of class members that support the expanded domain of genericity as part of a first layer of the subdivided version of the class, and the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity as part of a second layer of the subdivided version of the class.

8. The method of claim 7,

wherein the first layer is a generic layer including abstract versions of the one or more of the plurality of class members that support the expanded domain of genericity;

and

wherein the second layer is a reference-specific layer including a non-abstract version of at least one of the one or more of the plurality of class members for which abstract versions are included in the generic layer.

9. The method of claim 8, further comprising loading, by the platform independent, object oriented runtime environment, a fully generic version of the subdivided class, wherein said loading comprises:

including, by the platform independent, object oriented runtime environment, in the fully generic version of the subdivided class the one or more of the plurality of class members for which abstract versions are included in the generic layer; and

not including, by the platform independent, object oriented runtime environment, in the fully generic version of the subdivided class the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity.

10. The method of claim 8, further comprises loading, by the platform independent, object oriented runtime environment, a reference-specific version of the subdivided class, wherein said loading comprises:

not including, by the platform independent, object oriented runtime environment, in the reference-specific version of the subdivided class the one or more of the plurality of class members for which abstract versions are included in the generic layer; and

including, by the platform independent, object oriented runtime environment, in the reference-specific version of the subdivided class the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity.

11. The method of claim 8, further comprising specializing, by the platform independent, object oriented runtime environment, the subdivided class for a non-reference type parameterization, wherein said specializing comprises:

creating, by the platform independent, object oriented runtime environment, a specialized version of the subdivided class that includes the one or more of the plurality of class members for which abstract version are included in the generic layer; and

not including, by the platform independent, object oriented runtime environment, in the specialized version of the subdivided class the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity.

12. The method of claim 7, wherein the plurality of class members includes one or more of:

a method, a field, a constructor, or a nested type.

13. The method of claim 7, wherein said compatibility comprises one or more of source compatibility, binary compatibility, or behavioral compatibility.

14. A computing device, comprising:

a processor; and

a memory comprising program instructions, that when executed on the processor cause the processor to;

expand a domain of genericity of an existing generic class comprising a plurality of class members, wherein one or more of the plurality of class members do not support at least part of the expanded domain of genericity, wherein the domain of genericity comprises a range of types over which the generic class is eligible for specialization, wherein for the expanded domain of genericity the range of types includes one or more reference types and one or more non-reference types, wherein the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity do not support specialization for the one or more non-reference types;

wherein to expand the domain of genericity of the existing generic class the program instruction further cause the processor to;

create a subdivided version of the class that supports the expanded domain of genericity and preserves compatibility with the existing generic class, wherein to create the subdivided version of the class comprises;

include, in the subdivided version of the class, one or more indicators that identify one or more of the plurality of class members that support the expanded domain of genericity as part of a first layer of the subdivided version of the class and the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity as part of a second layer of the subdivided version of the class.

15. The computing device of claim 14,

wherein the first layer is a generic layer including abstract versions of the one or more of the plurality of class members that support the expanded domain of genericity;

and

wherein the second layer is a reference-specific layer including a non-abstract version of at least one of the one or more of the plurality of class members for which abstract versions are included in the generic layer.

16. The computing device of claim 15, wherein the program instruction further cause the processor to:

load a fully generic version of the subdivided class, wherein to load the fully generic version of the subdivided class, the program instruction further cause the processor to;

include in the fully generic version of the subdivided class the one or more of the plurality of class members for which abstract versions are included in the generic layer; and

not include in the fully generic version of the subdivided class the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity.

17. The computing device of claim 15, wherein the program instructions further cause the processor to:

load a reference-specific version of the subdivided class, wherein to load the reference-specific version of the subdivided class, the program instruction further cause the processor to;

not include in the reference-specific version of the subdivided class the one or more of the plurality of class members for which abstract versions are included in the generic layer; and

include in the reference-specific version of the subdivided class the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity.

18. The computing device of claim 15, wherein the program instructions further cause the processor to:

specialize the subdivided class for a non-reference type parameterization, wherein to specialize the subdivided class, the program instructions further cause the processor to;

create a specialized version of the subdivided class that includes the one or more of the plurality of class members for which abstract version are included in the generic layer; and

not include in the specialized version of the subdivided class the one or more of the plurality of class members that do not support at least part of the expanded domain of genericity.

19. The computing device of claim 14, wherein the plurality of class members include one or more of:

a method, a field, a constructor, or a nested type.

20. The computing device of claim 14, wherein said compatibility comprises one or more of source compatibility, binary compatibility, or behavioral compatibility.