Accommodating Data Heterogeneity in ULS Systems Christopher Scaffidi Mary Shaw Carnegie Mellon University

2 Problem: Data heterogeneity among software elements in ULS systems Software elements: –Created by autonomous stakeholders –Differing data formats –May switch to new formats without prior notice End-user programmers: –Create particularly unreliable software elements –“Mash up” (integrate) software elements problem  approach  proof-of-concept

3 Example: Exchanging person names John Smith today Smith, John tomorrow – unexpected format! unanticipated need for “glue code” to reformat Lincolnshire MCC tomorrow – questionable! need to validate data, maybe trigger fail-over Similar issues for data from users, external datasets, or the web. problem  approach  proof-of-concept

4 Other examples of data format heterogeneity Room Numbers –NSH 3103 vs Newell Simon Hall 3103 Stocks –GOOG vs Google vs Google Corporation Address Lines –101 Main St. vs 101 MAIN STREET vs 101 Main Str. Phone Numbers – vs vs (888) State Names –California vs CA vs Calif. problem  approach  proof-of-concept

5 Insight: Exchange kinds of data (rather than particular formats) John Smith Main St. Pittsburgh, PA Doe, Jane Brooke Lane PITTSBURGH Pennsylvania RAY TILL (404) PITT ST PGH, Penna. MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA MR. ART COR RED RUN RD. pittsburgh PA JOHN SMITH (303) MAIN ST Pittsburgh, PA problem  approach  proof-of-concept

6 Insight: Exchange kinds of data (rather than particular formats) Needed: Metadata indicating a reusable abstraction for validating and reformatting each kind of string-like data. –“I am sending you a string that I call a ‘phone number’, and here’s the code to validate it and reformat it” problem  approach  proof-of-concept

7 Proof of concept: Exchanging XML and HTML Data providers label XML/HTML nodes with a “tope” –“This node is what I call a ‘phone number’, and here’s where you can find code to validate and reformat it.” Each tope’s implementation is stored at a published URL On receiving data, a system –Downloads the tope implementation –Executes it to validate and put data into desired format problem  approach  proof-of-concept

8 Sample code XML Jan-96 (203) /30/2007 TopeSheet xpath:/mydoc/whatever/date{tope:url( xpath:/mydoc/whatever/tel{tope:url( Client Code ItemLoader loader = ItemLoader.FromXml(xml); ItemSet items = loader.Load("xpath:/*/tel"); List values = items.FormatAs(" "); // overloaded methods let you override the topes and/or validate the data problem  approach  proof-of-concept

9 Benefits of labeling strings with topes Systems can detect invalid inputs Software elements can use varying formats –No explicit references to format identifiers –No need for ontology consensus Topes are reusable for data in… –XML nodes  Database tuples –HTML tags  Webform fields –Spreadsheet cells  …and more problem  approach  proof-of-concept

10 Thank You… To Jeff Magee, Betty Cheng, Barbara Ryder, Margaret Burnett, and others at ICSE 2007 for early feedback To NSF for funding To ULSSIS for this opportunity to participate