Service Discovery with the Google Android Mobile Platform

Transcription

1 tesi di laurea Service Discovery with the Google Android Mobile Platform Anno Accademico 2007/2008 relatore Ch.mo prof. Stefano Russo correlatore Ing. Marcello Cinque candidato Marco Faiella Matr. 885/139

2 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.

3 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.

4 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

5 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 Why this framework? Ad-hoc system, independent from any fixed infrastructure. Framework Management Services Operating System (Win Mobile, Symbian, Android) Application Services System Components 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.

6 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 Kernel

7 Design of a Discovery Application 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. 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.

8 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.

9 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.

10 Client Side The Client Application Main Components: A service interface A proxy which handles the remote requests The application itself 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. When the Stub receives the response to its request, it notifies it to the main application through the Notify() method.

11 Device Interaction Overview (2/2) Server

12 An Example of Use

13 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)

14 Any Questions?