Anchoring method for computing an XPath expression

• US 20030200506A1
• Filed: 04/23/2002
• Published: 10/23/2003
• Est. Priority Date: 04/23/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Abe, Mari, Hori, Masahiro, Topol, Brad B., DeWitt, Scott D.
• Granted Patent: US 8,407,326 B2
• Time in Patent Office: Days
• US Class Current: 715/513
• CPC Class Codes: G06F 16/986 Document structures and storage, e.g. HTML extensions
• CPC Class Codes: G06F 40/131 Fragmentation of text files, e.g. creating reusable text-blocks; Linking to fragments, e.g. using XInclude; Namespaces
• CPC Class Codes: G06F 40/143 Markup, e.g. Standard Generalized Markup Language [SGML] or Document Type Definition [DTD]
• CPC Class Codes: H04L 67/561 Adding application-functional data or data for application control, e.g. adding metadata
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 67/565 Conversion or adaptation of application format or content adding application control or application functional data H04L67/561

Abstract

An anchoring method for generating an XPath expression. The method can include identifying a stable anchor in the transcodable markup along an axis shared by the selected node. An XPath expression can be generated for the stable anchor. Subsequently, an offset between the stable anchor and the selected node can be computed. Finally, the XPath expression for the stable anchor and the offset can be concatenated, the concatenation forming the XPath expression for the selected node.

Claims

1. An anchoring method for generating an XPath expression for a selected node in transcodable markup comprising the steps of:

identifying a stable anchor in the transcodable markup along an axis shared by the selected node;

generating an XPath expression for said stable anchor;

computing an offset between said stable anchor and the selected node; and

,

concatenating said offset and said XPath expression for said stable anchor, said concatenation forming the XPath expression for the selected node.

2. The anchoring method of claim 1, wherein said identifying step comprises the step of locating within the transcodable markup content which has been pre-determined to be unlikely to change over time.

3. The anchoring method of claim 1, wherein said identifying step comprises the step of locating within the transcodable markup a node with a unique trait selected from the group consisting of displayable headers, displayable footers, comments and text.

4. The anchoring method of claim 1, wherein said identifying step further comprises the steps of:

determining whether a stable anchor exists in the transcodable markup; and

,

if it is determined that a stable anchor does not exist within the transcodable markup, reporting said determination.

5. The anchoring method of claim 1, wherein said computing step comprises the steps of:

selecting an axis between the selected node and said stable anchor;

generating location steps for each node in said selected axis between the elected node and said stable anchor; and

,

concatenating said location steps to produce said offset.

6. The anchoring method of claim 5, wherein said step of generating location steps comprises the steps of, for each node in said selected axis between the selected node and said stable anchor, generating a node test based upon a name of said node, further generating an ordinal predicate defining a number of steps said node resides away from said stable anchor in said selected axis, and, combining said node test and said ordinal predicate to produce said location step for said node.

7. An anchoring method for generating an XPath expression for a selected node within transcodable content comprising the steps of:

transforming the transcodable content into a set of nodes in a document object model (DOM) and traversing each axis in said DOM in search of a node with a unique trait within a threshold distance;

if said node is found in one of said axes during said traversing step, and, generating an XPath expression based upon said unique trait, said XPath expression uniquely identifying said node as a stable anchor;

generating an offset for said node along an axis joining said stable anchor and the selected node; and

,

combining said generated XPath uniquely identifying said stable anchor and said generated offset, said combination producing an XPath expression for the selected node based upon said stable anchor.

8. The anchoring method of claim 7, wherein said step of identifying a unique trait comprises the step of locating within said node a trait which has been pre-determined to be unlikely to change over time.

9. The anchoring method of claim 7, wherein said step of identifying a unique trait comprises the step of locating within the said node a trait selected from the group consisting of displayable headers, displayable footers, comments, and text.

10. The anchoring method of claim 7, wherein said generating step comprises the steps of:

selecting an axis between the selected node and said stable anchor;

generating location steps for each node in said selected axis between the selected node and said stable anchor; and

,

concatenating said location steps to produce said offset.

11. A machine readable storage having stored thereon a computer program for generating an XPath expression for a selected node in transcodable markup, the computer program comprising a routine set of instructions for causing the machine to perform the steps of:

identifying a stable anchor in the transcodable markup along an axis shared by the selected node;

generating an XPath expression for said stable anchor;

computing an offset between said stable anchor and the selected node; and

,

concatenating said offset and said XPath expression for said stable anchor, said concatenation forming the XPath expression for the selected node.

12. The machine readable storage of claim 11, wherein said identifying step comprises the step of locating within the transcodable markup content which has been pre-determined to be unlikely to change over time.

13. The machine readable storage of claim 11, wherein said identifying step comprises the step of locating within the transcodable markup a node with a unique trait selected from the group consisting of displayable headers, displayable footers, comments, and text.

14. The machine readable storage of claim 11, wherein said identifying step further comprises the steps of:

determining whether a stable anchor exists in the transcodable markup; and

,

if it is determined that a stable anchor does not exist within the transcodable markup, reporting said determination.

15. The machine readable storage of claim 11, wherein said computing step comprises the steps of:

selecting an axis between the selected node and said stable anchor;

generating location steps for each node in said selected axis between the selected node and said stable anchor; and

,

concatenating said location steps to produce said offset.

16. The machine readable storage of claim 15, wherein said step of generating location steps comprises the steps of, for each node in said selected axis between the selected node and said stable anchor, generating a node test based upon a name of said node, further generating an ordinal predicate defining a number of steps said node resides away from said stable anchor in said selected axis, and, combining said node test and said ordinal predicate to produce said location step for said node.

17. A machine readable storage having stored thereon a computer program for generating an XPath expression for a selected node in transcodable markup, the computer program comprising a routine set of instructions for causing the machine to perform the steps of:

transforming the transcodable content into a set of nodes in a document object model (DOM) and traversing each axis in said DOM in search of a node with a unique trait within a threshold distance;

if said node is found in one of said axes during said traversing step, and, generating an XPath expression based upon said unique trait, said XPath expression uniquely identifying said node as a stable anchor;

generating an offset for said node along an axis joining said stable anchor and the selected node; and

,

combining said generated XPath uniquely identifying said stable anchor and said generated offset, said combination producing an XPath expression for the selected node based upon said stable anchor.

18. The machine readable storage of claim 17, wherein said step of identifying a unique trait comprises the step of locating within said node a trait which has been pre-determined to be unlikely to change over time.

19. The machine readable storage of claim 17, wherein said step of identifying a unique trait comprises the step of locating within the said node a trait selected from the group consisting of displayable headers, displayable footers, comments, and text.

20. The machine readable storage of claim 17, wherein said generating step comprises the steps of:

selecting an axis between the selected node and said stable anchor;

generating location steps for each node in said selected axis between the selected node and said stable anchor; and

,

concatenating said location steps to produce said offset.