tesi di laurea
relatore
Ch.mo prof. Stefano Russo
correlatore
Ing. Marcello Cinque
candidato
Marco Faiella Matr. 885/139
Service Discovery with the Google Android Mobile Platform
Background
The technological progresses in the last years have made the users able to dispose of several types of mobile devices.
The traditional distributed systems evolved in nomadic computing systems
Services Oriented Architectures
• The applications are developed as a collection of independent services, combined in order to obtain more complex functionalities.
• The services are not necessarily known a priori.
It is necessary a mechanism which would allow the user to know what services are provided in his physical location.
Objectives
Objective of this work is the development of a Discovery application running on the Google Android mobile platform and based on a services framework developed by the Università degli Studi di Napoli Federico II in partnership with the Wifi People company.
Why Android?
• Android is Open Source
• There are still few Discovery solutions available.
• Android has been our object of study at the University of Strathclyde during our permanence in Glasgow.
Service Discovery
Definition: a collection of protocols and mechanisms which help the device or the software to know
which services are available.
Functional Requirements
• Mobility Support • Dynamicity Support
• Completeness of the search mechanism
• Bounds definition
Non-functional Requirements
Scalability, Lightness, Heterogeneity, Reliability, Safety
A Services Framework
Designed in the research project between CINI (Consorzio Interuniversitario Nazionale per
l’Informatica) and the WiFi People company, called WiFi People – CRONOS
Fr am ew or k A ppl ic a ti on S e rv ices S y s te m C ompone nts
Operating System (Win Mobile, Symbian, Android)
M a na ge me nt S e rv ices
Why this framework?
• Ad-hoc system, independent from any fixed infrastructure.
• Automatic configuration and distribution • Transparence
The framework acts as a middleware, so a client application (implemented in any language) may easily access to the provided services through the Proxy pattern.
The Google Android mobile platform
A software stack for mobile devices including an operating system, middleware and key applications
Developed by Google Inc. and the Open Handset Alliance
Includes
• Applications • Application Framework • Java-based runtime • Libraries • Linux KernelDesign of a Discovery Application
Technical Requirements
• Send request for the available services • Show the available services as a list
• Select a service from the list and download it if not available on the device.
An Android-based Service Discovery application for the Core Framework. This application should make the user always able to keep up to date the services installed on his device and install new services when he needs.
Server
Side (1/2) – The Repository
The Repository is structured as directory trees.
• A root directory for each OS supported by the framework’s services
• A directory for each service
• A directory for each version of the services
An XML file, called latest.xml, keeps track of the latest version of the services for each OS.
Server Side (2/2) – The Discovery Service
Main Components:
• A service interface
• A proxy which handles the remote requests • The service itself
The Skeleton receives the requests from the client application through a socket connection.
The request is composed of an instruction code and one or more parameters.
Depending on the received code, the Skeleton invokes a method on the DiscoveryService.
Client Side – The Client Application
Main Components:
• A service interface
• A proxy which handles the remote requests
• The application itself
When the Stub receives the response to its request, it notifies it to the main application through the Notify() method.
The main application invokes the methods on the Stub.
The Stub creates a request message, with an instruction code and one or more parameters, and sends it to the Skeleton.
Interaction Overview (2/2)
Conclusions and Future Works
In the rapid and continuous spreading of the mobile technologies, the Services Oriented
Architectures represent a natural evolution for the applications.
The mobile device is, for the user, a key to interact with the environment. In this scenario the Service Discovery is quite an important tool.
In this work it has been developed a Discovery application provided with the basic functionalities for the Service Discovery.
Possible future upgrades:
• Implementation of a scanning function for the search of more discovery servers • Implementation of other search mechanism (i.e.: by class or by specific name)
