XML-Tuples & XML-Spaces V0.7 By David “Uncle Dave” Moffat Presented by: Shurug Al-Khalifa

2 Outline Overview of Tuple Spaces and XML-Spaces. Basic XML-Spaces & XML-Tuples operations. Database operations on XML-Spaces. Extended Database Queries on XML-Spaces.

3 Introduction Implementation of tuples and tuple-spaces using XML. Tuple  list of values (“Sam”, 7, 48.1). Tuple Space  public repository that contains tuples. Template  tuple set up for matching. Using XML for the tuples and the commands.

4 Definitions XML-tuple  list of data fields in an XML format. Data field  XML-tagged data. Ralph XML-tuple field values are strings. XML-space  tuple space with XML tuples. An XML-space: – Referenced by a name. – Located on a server.

5 Creating and Communicating with an XML-Space “do” method. Commands and parameters expressed in XML. XMLSpace xs = new XMLSpace (“MySpace”,“server.mine.org”);

6 Writing XML-Tuples to an XML- Space String strTuple=“ ”+ “ Ralph ”+ “ 33 ”+ “ ”+ “ ”; String strResult; strResult=xs.do(strTuple); Returns with If error, message with

7 Writing Several XML-Tuples at Once Concatenate several into one string. Ralph :

8 Matching XML-Tuples Create a template. Template  XML-Tuple where fields may or may not have value in them.

9 Reading XML-Tuples from an XML- Space Read only. Match a template. 33 Returns with If not Found, NULL is returned. If error, message with

10 Reading XML-Tuples from an XML- Space Read and remove. Match a template. 33 Returns with If not Found, NULL is returned. If error, message with

11 Reading XML-Tuples from an XML- Space If client has to find a match. Read  Read and remove  xs.do returns: Tuple if a match is found. If a match is not found, waits until tuple exists then returns it.

12 Reading Several XML-Tuples at Once Read only. Match a template. 33 Returns list of tuples with If not Found, NULL is returned. If error, message with

13 Reading Several XML-Tuples at Once Read and remove. Match a template. 33 Returns list of tuples with If not Found, NULL is returned. If error, message with

14 Counting the Number of Matching XML-Tuples Match a template. 33 Returns number of tuples found with If error, message with

15 Registering for XML-Space Events Event  operation on an XML-space. 1. XMLSpaceListener interface. 2. Register as a Listener. 3. Give a template to the space.

16 Registering for XML-Space Events . XMLSpaceListener interface. Interface XMLSpaceListener { handleXMLSpaceEvent(String tuple, String space, String host, long lNum, boolean bErr); } If error, message with in “tuple”.

17 Registering for XML-Space Events . Register as a Listener. 3. Give a template to the space. xs.addXMLSpaceListner(this,tplt) Can register for different operations and templates Template

18 XML-Space Queries Basic query = scan 33 Returns a tuple or a list of tuples with If not Found, NULL is returned. If error, message with

19 ANDing XML-Space Queries Match with two given query templates. : : Returns a tuple or a list of tuples with If not Found, NULL is returned. If error, message with

20 ORing XML-Space Queries Match with one or both given query templates. : : Returns a tuple or a list of tuples with If not Found, NULL is returned. If error, message with

21 Range Queries Match with values within template range. : : Returns a tuple or a list of tuples with If not Found, NULL is returned. If error, message with Upper Limit Lower Limit

Nested Queries : : : :

23 XML-Space Transactions Used to perform an operation only if it is successful. : : Everything is OK  Anything is unsuccessful 

24 Matching to Different “Depths” A field: - have content but not subfields be Null and have subfields. Karl Martin - have content and subfields

25 Partial XML-Tuple Templates Partial Template  does not specify all the fields or the subfields. Ann Arbor

26 Partial XML-Tuple Templates with Wildcards Used to match upper-level fields of template. Breadth-wise Ann Arbor Depth-wise Ann Arbor

27 Conclusion Tuple Spaces and XML-Spaces. Operations on XML-Spaces & XML-Tuples. Querying XML-Spaces.