Transcript Small devices in the prototype

Small Devices on DBGlobe
System
George Samaras
Chara Skouteli
Small Device Capabilities
 Wireless Connectivity
 GPRS
 GSM
 Bluetooth
 Infrared
 Wireless
 Development
 VBasic
 C/C++
 .NET
 Java
 WML
 HTML
Web Services
 Web services architecture is designed for B2B
application and desktop application, thus they
requires devices which:
Are always connected
Are able to process fast
Are powerful machines
 Small devices is difficult to use web services
because
Disconnections
Limited process capabilities
Low bandwidth
Connectivity Cost
Small devices as web services clients
Transferring Data with Web Services
SOAP
Client
(1) SOAP Request
(6) SOAP Response
Web
Server
(5) Http Response
(2) Http Request
(3)Java Call
Web Service
SOAP
Engine
(4) Java Object
However….
 Many big companies like IBM, Sun, Microsoft
e.t.c provide runtime environments with new
components to allow mobile devices to use web
services.
Java enable devices which using J2ME are unable
to parse soap messages, thus new runtime
environments and standards have been created:
 kSOAP
 J2ME-Web services API
 J2ME Wireless Connection Wizard Module
 JSR 172 J2ME Web Services Specification
Client Agent Server Architecture to support the usage of web
services on small devices
 Client Agent Server
Architecture is a good solution
in order to support web
services on mobile devices.
 We can use a light protocol for
client agent side
communication and agent
server side can stay as it is.
 This protocol can be consist by
a set of available open source
implementations like
 Enhydra
 kSOAP
 kXML
Request “Weather”
Response “Weather”
HTTP/SOAP
HTTP/SOAP
Small Devices as Web Service providers
Small devices as service providers
Small devices because of the problems we
mentioned earlier can not
Run a web server to handle http requests
Run a soap engine to handle soap messages
How to host a service available on a small
device?
 We can create a proxy of
the service on a web server
as the web service.
service
 The proxy knows how to
communicate with the
(2) Response
service on the device
 The service provider
registers the proxy service
as the available web service
Request (1)
Service
proxy
Web server
How to host a service available on a small
device? (cont.)
SOAP
Client
(1) SOAP Request
(6) SOAP Response
(2)Java Call
(3) Java Call
service
(4) Java Object
Web
Server
SOAP
Engine
Web Service
proxy
(5) Java Object
Bibliography
[1]V. Bansal, A. Dalton. A Performance Analysis of Web Services on Wireless PDAS.
Duke University Computer Sciences.
[2]Enhydra: Opensource initiateve to provide libraries like kXML,Ksoap,kUDDI for J2ME
[3] http://jcp.org/en/jsr/detail?id=172
[4] Java Web Services. H. Bequet, M. M. Kunnumpurath, S. Rhody and A. Tost
[5] http://www.alphaworks.ibm.com/tech/wstkmd
[6] http://www.ksoap.org/
[7] http://java.sun.com/
Appendix
The J2ME Wireless Connection Wizard Module
 The J2ME Wireless Connection Wizard Module builds
client and server communication components of an endto-end application
based on a simple specification that you provide.
These components provide you with
 all the efficiency and power of lightweight calls to remote
services
 without the complexity of hand-coding or
 the overhead of bulky generic libraries.
KSOAP
KSOAP is an open-source implementation
of Web services.
Have been optimized to run on small
mobile devices and support a subset of
the SOAP 1.1 specification, because of
limited amount of memory on these devices
 limited capabilities of the J2ME environment.
JSR 172 J2METM Web Services
Specification
JSR is designed to provide an infrastructure as two optional packages for J2ME to: provide basic XML processing capabilities
 enable reuse of web service concepts when designing J2ME clients to enterprise services
 provide APIs and conventions for programming J2ME clients of enterprise services
 adhere to web service standards and conventions around which the web services and Java
developer community is consolidating
 enable interoperability of J2ME clients with web services
 provide a programming model for J2ME client communication with web services, consistent with
that for other Java clients such as J2SE
The following technologies will be addressed:
 APIs for basic manipulation of structured XML data (parsing)

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these APIs will be based around a suitable strict subset of the APIs already defined by JAXP
APIs and conventions for enabling XML based RPC communication from J2ME, including
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definition of a strict subset of the WSDL to Java mappings defined by JSR-101 (JAX-RPC), suitable for J2ME
definition of stub APIs based on the mapping above for XML based RPC communication, which will focus around
subsetting the mapping and conventions produced by JSR-101.
definition of runtime APIs to support stubs generated according to this mapping supporting XML as a transport and
encoding component
Investigation of a suitable and compact encoding mechanism for XML based RPC messages
J2ME Mobile Information Device
Profile (MIDP)
The J2ME Mobile Information Device
Profile (MIDP) lets you write downloadable
applications and services for networkconnectable, battery-operated mobile
handheld devices such as cell phones,
two-way pagers, and Palm Pilots.
The Mobile Information Device Profile
(MIDP)
 The Mobile Information Device Profile (MIDP), combined
with the Connected Limited Device Configuration
(CLDC), is the Java runtime environment for today's
mobile information devices (MIDs) such as phones and
entry level PDAs.
 Provides:
 A core application functionality required by mobile applications
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including the user interface,
network connectivity,
local data storage,
and application lifecycle management
 packaged as a standardized Java runtime environmentand set
of Java APIs.