Method and Apparatus for Converting Legacy Programming Language Data Structures to Schema Definitions

• US 20090222467A1
• Filed: 05/12/2009
• Published: 09/03/2009
• Est. Priority Date: 08/29/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Fang, Sheng, Kalia, Suman K., Green, John H.
• Granted Patent: US 8,121,976 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/284 Relational databases
• CPC Class Codes: G06F 8/31 Programming languages or programming paradigms

Abstract

A method and apparatus for creating a schema definition from a language-specific metamodel of a data structure written in a legacy computer language involves walking through the nodes of the metamodel, and creating corresponding schema element objects in a schema tree that is serialized to create the schema definition. The creation of the schema element objects follows rules, and permits the definition of nested data structures having conjunctive-type and disjunctive-type membership.

Claims

1-19. -19. (canceled)

20. Apparatus for generating a schema definition from a definition of a nested data structure definition defined in a legacy computer language comprising:

a source code stored in a computer readable storage medium, wherein the source code is written in a legacy computer language, and wherein a plurality of identified data structures are identified by scanning the source code;

a Graphical User Interface (GUI) from which a nested data structure is selected from the plurality of identified data structures;

an interface through which a language-specific metamodel generated from the nested data structure definition is received;

a naming resource that generates names and definitions for a first complex type schema element for the nested data structure, wherein naming and defining comprises setting a content model of the first complex type schema element to sequence;

a data control system for walking through the language-specific metamodel to examine each node in a plurality of nodes of the language-specific metamodel, and for each node; and

a mapping module adapted to receive nodes, inspect their content, and generate a corresponding part of a schema definition according to a predefined mapped relationship to produce a schema definition for the nested data structure, wherein creating the schema definition further comprises populating a schema tree and serializing the schema tree after it is populated.

21. Apparatus as claimed in claim 20 wherein the language-specific metamodel is one of the COBOL metamodel, a C metamodel, a PL/I metamodel and a high level assembler metamodel.

22. Apparatus as claimed in claim 21 wherein the mapping module is adapted to create schema element objects from respective nodes, the schema element objects being arranged to form a schema sub-tree for the nested data structure, and the computer program further comprises a serialization procedure for saving the schema definition to a file.

23. Apparatus as claimed in claim 22 wherein the data control system performs a walk through by selecting successive nodes of the language-specific metamodel according to a breadth-first search algorithm.

24. Apparatus as claimed in claim 23 wherein the mapping module is adapted to inspect the node to determine a type of the node, and then to apply a mapping to the data structure in dependence upon the determined type of the node.

25. Apparatus as claimed in claim 24 wherein the mapping module creates simple type schema elements by assigning a name and data type to the element, and optionally assigning one or more of a data type restriction and an expected default value, in accordance with a native interpretation of the node.

26. Apparatus as claimed in claim 25 wherein the mapping module creates complex type schema elements as child objects of a root node of the schema tree, by assigning a name and a content model of choice or sequence, to the complex type schema elements.

27. Apparatus as claimed in claim 25 wherein the mapping module creates group schema elements by assigning a name, and a content model of choice or sequence, to the group schema elements.

28. Apparatus as claimed in claim 25 wherein the mapping module determines if the node defines an array, in which case a maximum and minimum number of fields in the array, a name of the base field and a type of the base field are included in a simple type schema element definition.

29. Apparatus as claimed in claim 28 wherein the mapping module further determines if the base field is of non-primitive type, in which case it further creates a complex type schema element for the base type.

30. A tangible computer storage medium having computer program instructions encoded thereon for generating a schema definition, comprising:

instructions for identifying a plurality of identified data structures by scanning a source code stored in a computer readable storage medium, wherein the source code is written in a legacy computer language;

instructions for selecting via a Graphical User Interface (GUI) a nested data structure from the plurality of identified data structures;

instructions for receiving a language-specific metamodel generated from the nested data structure definition written in the legacy computer language;

instructions for naming and defining a first complex type schema element for the nested data structure, wherein naming and defining comprises setting a content model of the first complex type schema element to sequence;

instructions for creating the schema definition by walking through the metamodel to examine each node in a plurality of nodes of the language-specific metamodel, and for each node, creating a respective schema element according to a predefined mapped relationship, wherein creating the schema definition further comprises populating a schema tree; and

serializing the schema tree after it is populated.

31. The medium tangible computer storage medium of claim 30 wherein the instructions for receiving comprises instructions for receiving a parse tree generated from the nested data structure definition written in one of C, PL/I, high level assembler and Cobol.

34. A tangible computer storage medium of claim 31 wherein instructions for populating a schema tree comprises:

instructions for selecting a first node from the plurality of nodes in the walk through the language-specific metamodel, in accordance with a breadth-first selection algorithm;

instructions for examining the respective schema element of the first node to determine a type of the elements, the type of the elements determined being a determined element type; and

instructions for applying the predefined mapped relationship to the first node in accordance with the determined element type to generate the respective schema element.

35. The tangible computer storage medium of claim 34 wherein the instructions for applying the predefined mapped relationship comprises:

instructions for generating the respective schema element by creating a first object of a type determined by the predefined mapped relationship, the type of the object determined being a determined object type;

instructions for specifying a first name for the first object; and

instructions for setting all required attributes of the first object according to the determined object type.

36. The tangible computer storage medium of claim 35 wherein the instructions for specifying the name for the first object comprises the instructions for deriving the name for the first object from a list of names of the first node, and ancestors of the node, in accordance with a naming convention.

37. The tangible computer storage medium of claim 35 wherein the instructions for generating the schema element comprises instructions for creating one of:

a group schema element;

a simple type schema element; and

a complex type schema element, in dependence upon the determined object type and the determined element type.

38. The tangible computer storage medium of claim 36 wherein the instructions for setting all the required attributes comprises:

instructions, if the schema element is the second complex type schema element or the group schema element, for setting a second content model to sequence or choice for all the schema element; and

instructions, if the schema element is the simple type schema element, for setting a data type for the schema element.

39. The tangible computer storage medium of claim 38 wherein the instructions for setting the data type comprises instructions for applying a mapping from a language-specific data type to a schema data type.

32-33. -33. (canceled)