Method and apparatus for converting legacy programming language data structures to schema definitions

• US 8,121,976 B2
• Filed: 05/12/2009
• Issued: 02/21/2012
• Est. Priority Date: 08/29/2002
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kalia, Suman K., Fang, Sheng, Green, John H.
• Primary Examiner(s): Breene, John E
• Assistant Examiner(s): Ly, Anh
• Application Number:
  US12/464,674
• Publication Number:
  US 20090222467A1
• Time in Patent Office: 1,015 Days
• Field of Search: 707/802, 707/803, 707/805, 707/807, 707/809, 707/811, 707/601, 707/806, 707/808, 717/104, 717/114, 717/116, 717/132, 717/136, 717/137
• US Class Current: 707/601
• 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. 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 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;

instructions for receiving nodes, inspecting content of the nodes, and generating a corresponding part of a schema definition according to a predefined mapped relationship to produce a schema definition for the nested data structure; and

instructions for serializing the schema tree after it is populated.

2. The tangible computer storage medium of claim 1 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.

3. The tangible computer storage medium of claim 2 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.

4. The tangible computer storage medium of claim 3 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.

5. The tangible computer storage medium of claim 4 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.

6. The tangible computer storage medium of claim 4 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.

7. The tangible computer storage medium of claim 5 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 the schema element; and

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

8. The tangible computer storage medium of claim 7 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.

9. The tangible computer storage medium of claim 1 wherein the language-specific metamodel is one of the COBOL metamodel, a C metamodel, a PL/I metamodel and a high level assembler metamodel.

10. The tangible computer storage medium of claim 1 wherein the instructions for generating a corresponding part of a schema definition according to a predefined mapped relationship to produce a schema definition for the nested data structure 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.

11. The tangible computer storage medium of claim 1 wherein the instructions for generating a corresponding part of a schema definition according to a predefined mapped relationship to produce a schema definition for the nested data structure 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.

12. The tangible computer storage medium of claim 11 wherein the instructions for generating a corresponding part of a schema definition according to a predefined mapped relationship to produce a schema definition for the nested data structure 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.

13. The tangible computer storage medium of claim 11 wherein the instructions for generating a corresponding part of a schema definition according to a predefined mapped relationship to produce a schema definition for the nested data structure 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.

14. The tangible computer storage medium of claim 13 wherein the instructions for generating a corresponding part of a schema definition according to a predefined mapped relationship to produce a schema definition for the nested data structure 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.