XML J2ME

1
XML J2ME

• Lars Engel(Engel.Lars_at_gmx.de)
• Mohamad Nabulsi (UID nabulsi)

2
Parser

• Different classifications
• Validation
• Validating parser it checks an XML document
  against a Document Type Definition DTD or schema
  to ensure that the content of the document fits
  to what the application expects
• Non-Validating it skips this step and just
  ensures that an XML document is well-formed
• Processing
• Model reads the entire document and creates a
  representation of the document in memory
• Push reads through an entire document. As it
  encounters various parts of the document, it
  notifies a listener object
• Pull reads a little bit of a document at once ?
  always ask to read next piece

3
Performance

• Runtime performance
• Network connection
• it may take a long time to set up the connection
• data transfer rate (may be slow)
• include as much information as possible
  avoid extra information
• Deployment Code size
• No much space on MIDP devices
• ? kXML is a balance between the above conditions

4
kXML

• kXML is specifically designed for KVM
  environments
• Originally developed at the university of
  Dortmund
• Pull based parser
• Small ( 24 KB)
• Stable and relatively mature

5
Concept
DB
Parser
generates structure with UUID
Suche
Request
Parse store locally
Index-Theme
getTheme
Cache/local memory
answer
save changes
6
GUIData
7
Interface XmlQuery

• Implemented by class de.tuberlin.ivs.mi.xmlparser
• Offers methodes to get and change data from DB
• Searchable get(long elementID)
• Searchable search(String search, int depth,
  String device, int filter)
• addNote(long destinationID, String content,
  String name)
• setLink(long id, long destinationID)

8
Xmlparser structure
HTTP
PicoreXTMParser
Interface XMLQuery
GUI
XParser
bpParser
bpWriter
rms
StorageManager
9
Persistant Storage in J2ME

• Differences to J2SE
• Class File
• does not exist
• realized by RecordStores which contain records
• Records store array of byte
• Serialization
• Has to be implemented explicitly
• Has to be as small as possible on the one hand,
  converting has to be as fast as possible on the
  other
• Slow

10
Storage of DB data
Xml data from DB
Hashtable toc over id rec
Theme A Note Source Link Theme
B Note Source Link Theme
C Note Source Link

Picore/XTM Parser
11
GUI requests a Searchable
XParser
bpParser
GUI
StorageManager
get(int id)
get(int id)
lookUp(int id)
getRecord(int id)
byte (wbxml)
parseForElement(int id)
Searchable