Declarative specification and engine for non-isomorphic data mapping

• US 20030110177A1
• Filed: 05/17/2002
• Published: 06/12/2003
• Est. Priority Date: 12/10/2001
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: BEA Systems Incorporated (Oracle Corporation)
• Inventors: Bosworth, Adam, Bau, David III, Andrei, Cezar Christian
• Granted Patent: US 6,859,810 B2
• Time in Patent Office: Days
• US Class Current: 707/100
• CPC Class Codes: G06F 16/88 Mark-up to mark-up conversion conversion for visualization in web browsing G06F16/9577
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

A mapping engine is provided to populate data elements of a first data structure of a first data representation with values of corresponding data elements of a second data structure of a second data representation, in accordance with at least a mapping specification. The two data structures may have different data shapes. The mapping specification may have a number of data element and data attribute mapping directives, including repeating data items. A population operation in a reversed direction may also be performed using the same mapping specification. The mapping specification may also specify an external mapping specification for a subset of the mapping operations. The external mapping specification may comprise unidirectional function pairs. In one embodiment, the mapping engine performs order dependent mapping facilitating the use of separate mapping rules for different instances of the same data element based upon the relative position of the data element instances within an input data structure.

Claims

1. A computer implemented method comprising:

receiving a first mapping specification mapping data elements of a first data structure of a first data representation to data elements of a second data structure of a second data representation, the first data structure having a first one or more data elements and a first one or more data element relationships defining a first shape and the second data structure having a second one or more data elements and a second one or more data element relationships defining a second shape, where the first shape and the second shape are not equivalent;

receiving a first instance of said first data structure having first instances of said first one or more data elements of said first data structure; and

populating data element instances of a first instance of said second data structure with values of said correspondingly mapped data element instances of said first instance of said first data structure in accordance with said first mapping specification.

2. The method of claim 1, where the method further comprises

receiving a second instance of said first data structure having second instances of said first one or more data elements of said first data structure;

and

populating said data element instances of said first instance of said second data structure with values of said correspondingly mapped data element instances of said second instance of said first data structure in accordance with said first mapping specification.

3. The method of claim 1, where the method further comprises

receiving a second instance of said second data structure having second instances of said second one or more data elements;

and

populating data element instances of a second instance of said first data structure with values of said correspondingly mapped data element instances of said second instance of said second data structure in accordance with said first mapping specification.

4. The method of claim 3, wherein said second instance of said second data structure comprises said populated data element instances of said second data structure.

5. The method of claim 4, wherein values of one or more of said data element instances of said populated data element instances of said second data structure are modified before populating said data element instances of said second instance of said first data structure.

6. The method of claim 1, wherein the method further comprises

receiving a second mapping specification mapping data elements of said first data structure of said first data representation to data elements of a third data structure of a third data representation, the third data structure having a third one or more data elements and a third one or more data element relationships defining a third shape, where the first shape and the third shape are not equivalent;

and

populating said data element instances of a first instance of said third data structure with values of said correspondingly mapped data element instances of said first instance of said first data structure in accordance with said second mapping specification.

7. The method of claim 6, wherein said third data representation comprises a selected one of the Extended Mark-Up Language elements and Java objects.

8. The method of claim 1, wherein said second data representation comprises a selected one of Extended Mark-Up Language elements and Java objects.

9. The method of claim 1, wherein said first programming language comprises a selected one of Extended Mark-Up Language elements and the Java objects.

10. The method of claim 1, wherein at least one of said first and second data representations comprise Extended Mark-Up Language elements, and said first mapping specification comprises an instance of one of said first and second data representations comprising said Extended Mark-Up Language elements and including a plurality of mapping tags specifying said mapping of data elements of said first data structure to said data elements of said second data structure.

11. The method of claim 10, wherein said mapping tags comprise an identifier prefix identifying a mapping namespace where semantics of said mapping tags are defined.

12. The method of claim 10, wherein at least one of said mapping tags is expressed in a shorthand form.

13. The method of claim 12, wherein said shorthand form comprises usage of a plurality of special characters as delimiters.

14. The method of claim 13, wherein said special characters comprise “

{” and

“

}”

.

15. The method of claim 10, wherein said mapping tags comprise a mapping tag specifying a mapping between an XML data element and a Java object.

16. The method of claim 10, wherein said mapping tags comprise a mapping tag specifying a mapping between an XML attribute and a Java object.

17. The method of claim 10, wherein said mapping tags comprise a mapping tag specifying a mapping of data between repeating XML tags and a Java collection object.

18. The method of claim 10, wherein said mapping tags comprise a mapping tag specifying a second mapping specification to be used to map a first subset of said mapping of said data elements of said first data structure to said data elements of said second data structure.

19. The method of claim 18, wherein said second mapping specification comprises a bi-directional mapping of said first subset of mapping of said data elements of said first data structure to said data elements of said second data structure.

20. The method of claim 18, wherein said second mapping specification comprises a first and a second unidirectional function performing said first subset of mapping of said data elements of said first data structure to said data elements of said second data structure in a first and a second mapping direction respectively.

21. The method of claim 20, wherein said first and second unidirectional functions are methods of a programming language class.

22. The method of claim 1, wherein said first and second data representations comprise Extended Mark-Up Language elements and Java objects respectively, and said populating operation comprises

initializing empty objects for each collection type and complex type appearing in at least said first mapping specification;

generating an annotated DOM tree representing mapping directives of said first data mapping specification; and

building data objects having corresponding values based at least in part on the annotated DOM tree representation.

23. The method of claim 22, wherein said initializing of empty objects is further based on a provided object type table.

24. The method of claim 22, wherein generating an annotated DOM further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying mapping between an XML data element and a Java object;

identifying an object name and object type associated with said directive and corresponding to said Java object, if said node corresponds to a mapping directive specifying mapping of an XML data element to said Java object; and

creating a new object containing the identified object name and object type, and replacing the selected node with the new object.

25. The method of claim 22, wherein generating an annotated DOM further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying mapping between an XML attribute and a Java object;

identifying an attribute name, an object name and object type associated with said directive and corresponding to said Java object, if said node corresponds to a mapping directive specifying mapping of an XML attribute to a Java object; and

creating a new object containing the identified attribute name, object name and object type, and replacing the selected node with the new attribute object.

26. The method of claim 22, wherein generating an annotated DOM further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying mapping between data within repeating XML tags and a Java collection object; and

identifying one or more collection names, one or more item names, and one or more item types corresponding to the mapping directive specifying mapping between data within repeating XML tags and a Java collection object, if said node corresponds to a mapping directive specifying mapping between data within repeating XML tags and a Java collection object; and

creating a new object containing said collection names, item names, and item types, and replacing the selected node with the new object.

27. The method of claim 22, wherein generating an annotated DOM further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying a second mapping specification to be used for a first subset of said mapping of said data elements of said first data structure to said data elements of said second data structure;

identifying a mapping signature of the selected node; and

creating a new object containing said mapping signature, and replacing the selected node with the new object.

28. The method of claim 22, wherein building further comprises:

parsing said first instance of said XML data structure having first instances of said first one or more data elements of said XML data structure to generate an input-DOM tree representing XML data elements;

creating a new target-node stack having a top-of-stack (TOS) containing one or more target nodes corresponding to nodes of said annotated DOM;

comparing each of said one or more target nodes with a selected input node of said input-DOM tree to determine if a search rule matches the selected input node.

30. The method of claim 28, further comprising:

selecting one of said one or more target nodes;

determining if said selected target node is a literal node matching said input node; and

pushing children of the selected target node onto the target-node stack if said selected target node is a literal node matching said input node.

31. The method of claim 30, further comprising:

determining if said selected target node corresponds to an object containing one or more collection names, item names, and item types, and if so, creating a new item instance for each corresponding collection item described by said object.

32. The method of claim 31, wherein creating a new item instance comprises:

instantiating an item associated with a corresponding item type described by the object;

binding said instantiated item to a corresponding item name described by the object; and

inserting said instantiated item into a corresponding collection described by the object.

33. The method of claim 28, further comprising:

selecting one of said one or more target nodes; and

assigning a value associated with said selected input node to an object corresponding to said selected target node, if said selected input node is an attribute node and a name associated with the attribute node matches the attribute name contained by the object;

34. The method of claim 28, further comprising:

selecting one of said one or more target nodes;

determining if said selected target node is associated with a value mapping object and if said selected input node is a text node; and

assigning a value associated with the text node to an object corresponding to the value object.

35. The method of claim 28, further comprising:

selecting one of said one or more target nodes;

determining if said selected target node corresponds to a second map specifying one or more objects within the second map signature;

passing the selected input node as a parameter to said second map if said selected target node corresponds to a second map specifying one or more objects within the second map signature; and

assigning objects returned by the second map to objects specified in the second map signature.

36. The method of claim 28, wherein each of said one or more target nodes are compared with said selected input node of said input-DOM tree in order such that different search rules can be used on XML data elements based on their position within said input-DOM tree.

37. The method of claim 36, wherein a marker is used to track which of the one or more target nodes said selected input node has been compared against.

38. The method of claim 1, wherein said first and second data representations comprise Java objects and Extended Mark-Up Language elements respectively, and said populating operation comprises

generating an annotated DOM tree representing XML-mapping directives of said first mapping specification;

traversing nodes of said annotated DOM tree representation in order, successively selecting and processing each node and child node in accordance with one or more XML-mapping directives corresponding to each said child node; and

outputting and appending the results of said processing in terms of XML accordingly.

39. The method of claim 38, wherein said processing comprises determining whether a selected node comprises a mapping directive specifying an XML value or attribute, and if so, retrieving an object associated with said value or attribute, evaluating said object to obtain a result, and appending said result to said XML output using an appropriate XML output format based at least in part upon whether said mapping directive specifies an XML value or attribute.

40. The method of claim 38, wherein said processing comprises:

determining whether a selected node corresponds to a second map specifying one or more objects within the second map signature;

passing the one or more specified objects as parameters to the second map; and

appending results of the second map to the XML output.

41. The method of claim 38, wherein said processing comprises:

determining if a selected literal node contains a child node that corresponds to a directive specifying mapping for repeating XML elements;

identifying a collection name and an item name associated with the corresponding directive;

binding said item name to a first item in a collection corresponding to said collection name;

outputting a literal start tag associated with said directive;

recursively appending each child node to the XML output using a value corresponding to the collection item bound to said item name; and

outputting a literal end tag associated with said directive.

42. The method of claim 38, wherein said processing of each child node comprises determining whether a selected child node comprises a mapping directive specifying usage of a second mapping specification comprising a pair of mapping functions, and if so, calling one of said mapping functions.

43. The method of claim 38, wherein said processing of each child node comprises determining whether the child node comprises a mapping directive specifying mapping for repeating XML data elements, and if so, iterating over corresponding collections to populate said repeating XML data elements.

29. The method of 28, further comprising successively selecting each input node of said input-DOM tree and comparing each selected input node to each of said one or more target nodes.

44. A computer implemented method for populating data elements of a Java data structure comprising one or more data objects and one or more data object relationships defining a first shape, with values of corresponding data elements of a XML data structure having a second one or more data elements and one or more data element relationships defining a second shape, where the first shape and second shape are not equivalent, the method comprising:

initializing empty objects for each collection type and complex type appearing in at least a mapping specification specifying mapping of said data elements of said XML data structure to corresponding data objects of said Java data structure;

generating an annotated DOM tree representing mapping specifications of said data mapping specification; and

building data objects having corresponding values based at least in part on the annotated DOM tree representation.

45. The method of claim 44, wherein said initializing of empty objects is further based on a provided object type table.

46. The method of claim 44, wherein annotating further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying mapping between an XML data element and a Java object;

identifying an object name and object type associated with said directive and corresponding to said Java object, if said node corresponds to a mapping directive specifying mapping of an XML data element to said Java object; and

creating a new object containing the identified object name and object type, and replacing the selected node with the new object.

47. The method of claim 44, wherein annotating further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying mapping between an XML attribute and a Java object;

identifying an attribute name, an object name and object type associated with said directive and corresponding to said Java object, if said node corresponds to a mapping directive specifying mapping of an XML attribute to a Java object; and

creating a new object containing the identified attribute name, object name and object type, and replacing the selected node with the new attribute object.

48. The method of claim 44, wherein annotating further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying mapping between data within repeating XML tags and a Java collection object; and

identifying one or more collection names, one or more item names, and one or more item types corresponding to the mapping directive specifying mapping between data within repeating XML tags and a Java collection object, if said node corresponds to a mapping directive specifying mapping between data within repeating XML tags and a Java collection object; and

creating a new object containing said collection names, item names, and item types, and replacing the selected node with the new object.

49. The method of claim 44, wherein annotating further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying a second mapping specification to be used for a first subset of said mapping of said data elements of said first data structure to said data elements of said second data structure;

identifying a mapping signature of the selected node; and

creating a new object containing said mapping signature, and replacing the selected node with the new object.

50. The method of claim 44, wherein building further comprises:

parsing said first instance of said XML data structure having first instances of said first one or more data elements of said XML data structure to generate an input-DOM tree representing XML data elements;

creating a new target-node stack having a top-of-stack (TOS) containing one or more target nodes corresponding to nodes of said annotated DOM;

comparing each of said one or more target nodes with a selected input node of said input-DOM tree to determine if a search rule matches the selected input node.

52. The method of claim 50, further comprising:

selecting one of said one or more target nodes;

determining if said selected target node is a literal node matching said input node; and

pushing children of the selected target node onto the target-node stack if said selected target node is a literal node matching said input node.

53. The method of claim 52, further comprising:

determining if said selected target node corresponds to an object containing one or more collection names, item names, and item types, and if so, creating a new item instance for each corresponding collection item described by said object.

54. The method of claim 53, wherein creating a new item instance comprises:

instantiating an item associated with a corresponding item type described by the object;

binding said instantiated item to a corresponding item name described by the object; and

inserting said instantiated item into a corresponding collection described by the object.

55. The method of claim 50, further comprising:

selecting one of said one or more target nodes; and

assigning a value associated with said selected input node to an object corresponding to said selected target node, if said selected input node is an attribute node, and a name associated with the attribute node matches the attribute name contained by the object;

56. The method of claim 50, further comprising:

selecting one of said one or more target nodes;

determining if said selected target node is associated with a value mapping object and if said selected input node is a text node; and

assigning a value associated with the text node to an object corresponding to the value object.

57. The method of claim 50, further comprising:

selecting one of said one or more target nodes;

determining if said selected target node corresponds to a second map specifying one or more objects within the second map signature;

passing the selected input node as a parameter to said second map if said selected target node corresponds to a second map specifying one or more objects within the second map signature; and

assigning objects returned by the second map to objects specified in the second map signature.

58. The method of claim 50, wherein each of said one or more target nodes are compared with said selected input node of said input-DOM tree in order such that different search rules can be used on XML data elements based on their position within said input-DOM tree.

59. The method of claim 58, wherein a marker is used to track which of the one or more target nodes said selected input node has been compared against.

51. The method of 50, further comprising successively selecting each input node of said input-DOM tree and comparing each selected input node to each of said one or more target nodes.

60. A computer implemented method for populating data elements of a XML data structure having a first one or more data elements and one or more data element relationships defining a first shape, with values of corresponding data objects of a Java data structure having a second one or more data elements and data element relationships defining a second shape, where the first shape and second shape are not equivalent, the method comprising:

generating an annotated DOM tree representing XML-mapping directives of said first mapping specification;

traversing nodes of said annotated DOM tree representation in order, successively selecting and processing each child node; and

outputting and appending the results of said processing according for XML values and XML attributes.

61. The method of claim 60, wherein said processing comprises determining whether a selected node comprises a mapping directive specifying an XML value or attribute, and if so, retrieving an object associated with said value or attribute, evaluating said object to obtain a result, and appending said result to said XML output using an appropriate XML output format based at least in part upon whether said mapping directive specifies an XML value or attribute.

62. The method of claim 60, wherein said processing comprises:

determining whether a selected node corresponds to a second map specifying one or more objects within the second map signature;

passing the one or more specified objects as parameters to the second map; and

appending results of the second map to the XML output.

63. The method of claim 60, wherein said processing comprises:

determining if a selected literal node contains a child node that corresponds to a directive specifying mapping for repeating XML elements;

identifying a collection name and an item name associated with the corresponding directive;

binding said item name to a first item in a collection corresponding to said collection name;

outputting a literal start tag associated with said directive;

recursively appending each child node to the XML output using a value corresponding to the collection item bound to said item name; and

outputting a literal end tag associated with said directive.

64. The method of claim 60, wherein said processing of each child node comprises determining whether a selected child node comprises a mapping directive specifying usage of a second mapping specification comprising a pair of mapping functions, and if so, calling one of said mapping functions.

65. The method of claim 60, wherein said processing of each child node comprises determining whether the child node comprises a mapping directive specifying mapping for repeating XML data elements, and if so, iterating over corresponding collections to populate said repeating XML data elements.

66. An article of manufacture comprising a storage medium having stored therein a plurality of programming instructions designed to program an apparatus to perform a data mapping, which programming instructions when executed enable the apparatus to

receive a first mapping specification mapping data elements of a first data structure of a first data representation to data elements of a second data structure of a second data representation, the first data structure having a first one or more data elements and a first one or more data element relationships defining a first shape and the second data structure having a second one or more data elements and a second one or more data element relationships defining a second shape, where the first shape and the second shape are not equivalent;

receive a first instance of said first data structure having first instances of said first one or more data elements of said first data structure; and

populate data element instances of a first instance of said second data structure with values of said correspondingly mapped data element instances of said first instance of said first data structure in accordance with said first mapping specification.

67. The article of claim 66, wherein the programming instructions further enable the apparatus to

receive a second instance of said first data structure having second instances of said first one or more data elements of said first data structure;

and

populate said data element instances of said first instance of said second data structure with values of said correspondingly mapped data element instances of said second instance of said first data structure in accordance with said first mapping specification.

68. The article of claim 66, wherein the programming instructions further enable the apparatus to

receive a second instance of said second data structure having second instances of said second one or more data elements;

and

populate data element instances of a second instance of said first data structure with values of said correspondingly mapped data element instances of said second instance of said second data structure in accordance with said first mapping specification.

69. The article of claim 68, wherein said second instance of said second data structure comprises said populated data element instances of said second data structure.

70. The article of claim 69, wherein values of one or more of said data element instances of said populated data element instances of said second data structure are modified before populating said data element instances of said second instance of said first data structure.

71. The article of claim 66, wherein the programming instructions further enable the apparatus to

receive a second mapping specification mapping data elements of said first data structure of said first data representation to data elements of a third data structure of a third data representation, the third data structure having a third one or more data elements and a third one or more data element relationships defining a third shape, where the first shape and the third shape are not equivalent;

and

populate said data element instances of a first instance of said third data structure with values of said correspondingly mapped data element instances of said first instance of said first data structure in accordance with said second mapping specification.

72. The article of claim 71, wherein said third data representation comprises a selected one of the Extended Mark-Up Language elements and Java objects.

73. The article of claim 66, wherein said second data representation comprises a selected one of Extended Mark-Up Language elements and Java objects.

74. The article of claim 66, wherein said first programming language comprises a selected one of Extended Mark-Up Language elements and the Java objects.

75. The article of claim 66, wherein at least one of said first and second data representations comprise Extended Mark-Up Language elements, and said first mapping specification comprises an instance of one of said first and second data representations comprising said Extended Mark-Up Language elements and including a plurality of mapping tags specifying said mapping of data elements of said first data structure to said data elements of said second data structure.

76. The article of claim 75, wherein said mapping tags comprise an identifier prefix identifying a mapping namespace where semantics of said mapping tags are defined.

77. The article of claim 75, wherein at least one of said mapping tags is expressed in a shorthand form.

78. The article of claim 77, wherein said shorthand form comprises usage of a plurality of special characters as delimiters.

79. The article of claim 78, wherein said special characters comprise “

{” and

“

}”

.

80. The article of claim 75, wherein said mapping tags comprise a mapping tag specifying a mapping between an XML data element and a Java object.

81. The article of claim 75, wherein said mapping tags comprise a mapping tag specifying a mapping between an XML attribute and a Java object.

82. The article of claim 75, wherein said mapping tags comprise a mapping tag specifying a mapping of data between repeating XML tags and a Java collection object.

83. The article of claim 75, wherein said mapping tags comprise a mapping tag specifying a second mapping specification to be used to map a first subset of said mapping of said data elements of said first data structure to said data elements of said second data structure.

84. The article of claim 83, wherein said second mapping specification comprises a bi-directional mapping of said first subset of mapping of said data elements of said first data structure to said data elements of said second data structure.

85. The article of claim 83, wherein said second mapping specification comprises a first and a second unidirectional function performing said first subset of mapping of said data elements of said first data structure to said data elements of said second data structure in a first and a second mapping direction respectively.

86. The article of claim 85, wherein said first and second unidirectional functions are methods of a programming language class.

87. The article of claim 66, wherein said first and second data representations comprise Extended Mark-Up Language elements and Java objects respectively, and said populating operation comprises

initializing empty objects for each collection type and complex type appearing in at least said first mapping specification;

generating an annotated DOM tree representing mapping directives of said first data mapping specification; and

building data objects having corresponding values based at least in part on the annotated DOM tree representation.

88. The article of claim 87, wherein said initializing of empty objects is further based on a provided object type table.

89. The article of claim 87, wherein said generating an annotated DOM further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying mapping between an XML data element and a Java object;

identifying an object name and object type associated with said directive and corresponding to said Java object, if said node corresponds to a mapping directive specifying mapping of an XML data element to said Java object; and

creating a new object containing the identified object name and object type, and replacing the selected node with the new object.

90. The article of claim 87, wherein generating an annotated DOM further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying mapping between an XML attribute and a Java object;

identifying an attribute name, an object name and object type associated with said directive and corresponding to said Java object, if said node corresponds to a mapping directive specifying mapping of an XML attribute to a Java object; and

creating a new object containing the identified attribute name, object name and object type, and replacing the selected node with the new attribute object.

91. The article of claim 87, wherein generating an annotated DOM further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying mapping between data within repeating XML tags and a Java collection object; and

identifying one or more collection names, one or more item names, and one or more item types corresponding to the mapping directive specifying mapping between data within repeating XML tags and a Java collection object, if said node corresponds to a mapping directive specifying mapping between data within repeating XML tags and a Java collection object; and

creating a new object containing said collection names, item names, and item types, and replacing the selected node with the new object.

92. The article of claim 87, wherein generating an annotated DOM further comprises:

selecting a node of the DOM tree;

determining if said node corresponds to a mapping directive specifying a second mapping specification to be used for a first subset of said mapping of said data elements of said first data structure to said data elements of said second data structure;

identifying a mapping signature of the selected node; and

creating a new object containing said mapping signature, and replacing the selected node with the new object.

93. The article of claim 87, wherein said building operation further comprises:

parsing said first instance of said XML data structure having first instances of said first one or more data elements of said XML data structure to generate an input-DOM tree representing XML data elements;

creating a new target-node stack having a top-of-stack (TOS) containing one or more target nodes corresponding to nodes of said annotated DOM;

comparing each of said one or more target nodes with a selected input node of said input-DOM tree to determine if a search rule matches the selected input node.

94. The article of claim 93, wherein the plurality of programming instructions further enable the apparatus to successively select each input node of said input-DOM tree and compare each selected input node to each of said one or more target nodes.

95. The article of claim 93, wherein the programming instructions further enable the apparatus to

select one of said one or more target nodes;

determine if said selected target node is a literal node matching said input node;

and

push children of the selected target node onto the target-node stack if said selected target node is a literal node matching said input node.

96. The article of claim 95, wherein the programming instructions further enable the apparatus to

determine if said selected target node corresponds to an object containing one or more collection names, item names, and item types, and if so, create a new item instance for each corresponding collection item described by said object.

97. The article of claim 96, wherein said programming instructions to create a new item instance comprises programming instructions to

instantiate an item associated with a corresponding item type described by the object;

bind said instantiated item to a corresponding item name described by the object; and

insert said instantiated item into a corresponding collection described by the object.

98. The article of claim 93, wherein the programming instructions further enable the apparatus to

select one of said one or more target nodes;

and

assign a value associated with said selected input node to an object corresponding to said selected target node, if said selected input node is an attribute node and a name associated with the attribute node matches the attribute name contained by the object;

99. The article of claim 93, wherein the programming instructions further enable the apparatus to

select one of said one or more target nodes;

determine if said selected target node is associated with a value mapping object and if said selected input node is a text node; and

assign a value associated with the text node to an object corresponding to the value object.

100. The article of claim 93, wherein the programming instructions further enable the apparatus to

select one of said one or more target nodes;

determine if said selected target node corresponds to a second map specifying one or more objects within the second map signature;

pass the selected input node as a parameter to said second map if said selected target node corresponds to a second map specifying one or more objects within the second map signature; and

assign objects returned by the second map to objects specified in the second map signature.

101. The article of claim 93, wherein each of said one or more target nodes are compared with said selected input node of said input-DOM tree in order such that different search rules can be used on XML data elements based on their position within said input-DOM tree.

102. The article of claim 101, wherein a marker is used to track which of the one or more target nodes said selected input node has been compared against.

103. The article of claim 66, wherein said first and second data representations comprise Java objects and Extended Mark-Up Language elements respectively, and said populating operation comprises

generating an annotated DOM tree representing XML-mapping directives of said first mapping specification;

traversing nodes of said annotated DOM tree representation in order, successively selecting and processing each node and child node in accordance with one or more XML-mapping directives corresponding to each said child node; and

outputting and appending the results of said processing in terms of XML accordingly.

104. The article of claim 103, wherein said processing comprises determining whether as selected node comprises a mapping directive specifying an XML value or attribute, and if so, retrieving an object associated with said value or attribute, evaluating said object to obtain a result, and appending said result to said XML output using an appropriate XML output format based at least in part upon whether said mapping directive specifies an XML value or attribute.

105. The article of claim 103, wherein said processing comprises:

determining whether a selected node corresponds to a second map specifying one or more objects within the second map signature;

passing the one or more specified objects as parameters to the second map; and

appending results of the second map to the XML output.

106. The article of claim 103, wherein said processing comprises:

determining if a selected literal node contains a child node that corresponds to a directive specifying mapping for repeating XML elements;

identifying a collection name and an item name associated with the corresponding directive;

binding said item name to a first item in a collection corresponding to said collection name;

outputting a literal start tag associated with said directive;

recursively appending each child node to the XML output using a value corresponding to the collection item bound to said item name; and

outputting a literal end tag associated with said directive.

107. The article of claim 103, wherein said processing of each child node comprises determining whether a selected child node comprises a mapping directive specifying usage of a second mapping specification comprising a pair of mapping functions, and if so, calling one of said mapping functions.

108. The article of claim 103, wherein said processing of each child node comprises determining whether the child node comprises a mapping directive specifying mapping for repeating XML data elements, and if so, iterating over corresponding collections to populate said repeating XML data elements.