Structure of Mobile Computing Application
Programming languages are used for mobile system software. Operating system functions to run the software components onto the hardware. Middleware components deployment. Layered structure arrangement of mobile computing components is used. Protocols and layers are used for transmission and reception.
Programming Languages
The following are the programming languages used for Mobile Computing applications are:
· Java - J2SE.
· J2ME (Java2 Micro edition)
· JavaCard (Java for smart card)
· The Java enterprise edition (J2EE) used for web and enterprise server based applications of mobile services
· C and C++
· Visual C++
· Visual Basic
Operating System
Symbian OS, Window CE, Mac OS are the operating systems used in Mobile computing applications. It offers the user to run an application without considering the hardware specifications and functionalities. It provides functions which are used for scheduling the multiple tasks in a system.
It provides the functions required for the synchronization of multiple tasks in the system. It uses multiple threads synchronization and priority allocation. Management functions (such as creation, activation, deletion, suspension, and delay) are used for tasks and memory. It provides Interfaces for communication between software components at the application layer, middleware layers, and hardware devices.
It facilitates the execution of software components on diversified hardware. It provides Configurable libraries for the GUI (graphic user interface) in the device. It provides
User application‘s GUIs, VUI (voice user interface) components, and phone API. It provides the device drivers for the keyboard, display, USB, and other devices.
Middleware
Software components that link the application components with the network-distributed components. It is used to discover the nearby device such as Bluetooth. It is used to discover the nearby hot spot for achieving device synchronization with the server or an enterprise server. It is used for retrieving data (which may be in Oracle or DB2) from a network database. It is used for service discovery at network. It is used for adaptation of the application to the platform and service availability.
Architecture of Mobile Computing Applications
Client/server architecture (and its variants) is often adopted for this kind of applications. However we have to take into consideration some specific aspects related to the mobile devices (clients), and their connectivity with servers.
Clients
There are many mobile device types, including RIM devices, cellular telephones, PDAs, Tablet, PCs, and Laptop PCs. These mobile devices can typically operate as thin clients or fat clients, or they can be developed so that they can host web pages
Thin Clients
Thin clients have no custom application code and completely rely on the server for their functionality. They do not depend as heavily on the mobile device‘s operating system or the mobile device type as fat clients. Thin clients typically use widely available web and Wireless Application Protocol (WAP) browsers to display the application content pages.
Fat Clients
Fat clients typically have one to three layers of application code on them and can operate independently from a server for some period of time. Typically, fat clients are most useful in situations where communication between a client and server cannot be guaranteed.
For example, a fat client application may be able to accept user input and store data in a local database until connectivity with the server is re-established and the data can be moved to the server.
This allows a user to continue working even if he/she is out of contact with the server. Fat clients depend heavily on the operating system and mobile device type and the code can be difficult to release and distribute. Fat clients can be implemented using one, two, or three layers of application code. However, if you only use one layer it is extremely difficult to isolate the individual areas of functionality and reuse and distribute the code over multiple device types.