Lecture 07: Technology and Standards

Question 1

What is a Rich Internet Application (RIA)?

Answer 1

A rich internet application is a web application which delivers, services, features and functions which are usually associated with a desktop software or desktop application.
There is greater emphasis on providing a service, rather than licensing, distribution and software packages.
The processing taken place within the application is split across a Client and Server side.
- Updates / Upgrades are automatic
- Consistent user experiences
- Less prone to viral infection

Question 2

What is AJAX?

Answer 2

AJAX stands for Asynchronous Javascript and XML, a group of technologies that drive web 2.0 applications a services. AJAX improves the dynamism of web pages, by updating them asynchronously by exchanging small amounts of data with the server, which updates the webpage without contacting the server. An AJAX application is browser and platform independent.

Question 3

How does AJAX work?

Answer 3

Browser:

1. An event occurs which creates an XMLHttpRequest
2. Send the HTTPRequest to the Server.
3. Processes the returned response using JavaScript
4. Updates the pages contents

Server:

3. Processes the HTTP Request
4. Creates a response and sends it back to the browser

The core is the AJAX engine between the web server and the user interface:

• It acts as an intermediary
• Sits within the client’s browser
• Facilitates asynchronous communication with the server of smaller items of information.

Question 4

What are the 8 AJAX Technologies?

Answer 4

1. HTML / XHTML - presenting information
2. CSS - look and formatting
3. DOM - a way of dynamically controlling the document
4. XML - text-based data exchange format
5. JSon - text-based data exchange format
6. JavaScript - scripting language embedded in browers

Question 5

What is XML?

Answer 5

XML is a software and hardware independent tool for storing and transporting data. It is a markup language and is self-descriptive.

Question 6

What are the differences between XML and HTML: Different Design Goals ?

Answer 6

• XML was designed to carry data with a focus on what data is.
• HTML was designed to display data with a focus on what data looks like
• XML tags are not predefined
• HTML tags are

Question 7

What are the four things XML simplifies?

Answer 7

1. Data Sharing
2. Data Transport
3. Platform Changes
4. Data Availability

Question 8

What is XSL?

Answer 8

XSL stands for Extensible Stylesheet Language and is a stylesheet language for XML documents.

Question 9

What is XSLT?

Answer 9

XSLT stands for Extensible Transformations and is a language to transform XML documents into other formats like XHTML.

Question 10

What is JavaScript Object Notation (JSON)?

Answer 10

JavaScript Objection Notation (JSON) is a data interchange format , which is used to import and export between platforms. It is programming language independent, is not a markup language and is based on the object literals of JavaScript.
It offers:
- Friendly data structures
- Friendly conventions
- Collaborates well with others

Question 11

What is ADOBE FLASH?

Answer 11

Adoble Flash is an alternative to HTML5 and AJAX. Its use has declined in recent times, but provided a method for sophisticated, quick-to-download vector graphics and animations to be displayed in browser. It was installed via a browser plug-in but was a software for streaming multimedia content.

Question 12

What are the four technologies around distributed computing?

Answer 12

1. CORBA (Common Object Request Broker Architecture): enables communication between software written in different languages running on different computers. Very powerful, limited in its way of using the internet in terms of the internet’s power and flexibility.
2. DCOM (Distributed Component Object Model): platform for Microsoft components
3. RMI (Remote Method Invocation): platform for Java components, compatible with “CORBA”.
4. Web Services (W3C): evolution of distributed computing using web standards

Question 13

What are Web Services?

Answer 13

A web service is a standards-based, language agnostic software entity that accepts specially formatted requests from other software entities on remote stations via vendor and transport neutral communication protocols producing application specific responses.
- A programmatic interface, lightweight or simplified programming models which facilitate the creation of loosley coupled systems which make few assumptions about each other, limit dependencies and employ communication techniques,

Question 14

What are the two schools of thought in developing web services?

Answer 14

1. SOAP (Simple Object Access Protocol): traditional and standards based approach
2. REST (Representative State Transfer): conceptually, simpler, trendier.

Question 15

What is the Simple Object Access Protocol (SOAP)?

Answer 15

Simple Object Access Protocol (SOAP) is a lightweight protocol for exchanging structured information in a decentralised and distributed environment. It defines a messaging framework containing a message construct through XML, that can exchanged over a variety of protocols.

Question 16

What is the Simple Object Access Protocol (SOAP) header used for?

Answer 16

Contains meta-information which is used for:

• Naming the encryption mechanism
• Access control information
• Routing information
• Auditing information
• Other data extensions which cannot fit into the body.

Question 17

What are the advantages of the Simple Object Access Protocol (SOAP)?

Answer 17

1. Language, platform and transport agnostic
2. Designed to handle distributed computing environments
3. Prevailing standard for web services, with better support from other standards and tools
4. Built-in error handling
5. Extensibility
6. Tools available

Question 18

What are the disadvantages of the Simple Object Access Protocol (SOAP)?

Answer 18

1. Conceptually a little difficult
2. A little verbose
3. Harder to develop - you need tools

Question 19

What is the Representative State Transfer Protocol (REST)?

Answer 19

Emerged as a reaction to the heavy-weight SOAP-based standards, with a greater emphasis on point-to-point communications. It requires a REST protocol like HTTP which defines: ACTIONS (GET, POST) and Resources (URIs)

Question 20

What are the advantages of the Representative State Transfer Protocol (REST)?

Answer 20

1. Language and platform agnostic
2. Simpler to develop than SOAP
3. Small learning curve, less reliance on tools
4. Concise, no need for additional messaging layer

Question 21

What are the disadvantages of the Representative State Transfer Protocol (REST)?

Answer 21

1. Assumes a point-to-point communication model, not usable for distributed environment with intermediaries.
2. Lack of standards support for security, policy, reliable messaging
3. Harder to develop.
4. Tied to the HTTP transport model.

Question 22

What are Open APIs?

Answer 22

Application Programming Interfaces are is a mechanism for a programmer to use in order to use the functionality of programs without their source code. An application programming interface is open when it does not require license or royalties.

Question 23

What are Microformats / Microdata?

Answer 23

Microformats are tiny bits of information which are injected into web pages, they do not affect how the web page is rendered but makes them smarter in terms of processing, understanding and searching the web.
Microdata provide additional semantics and provides a way to define customised elements and embed custom properties into web pages.

Question 24

What is the problem around Microformats?

Answer 24

If everybody decided to use their own semantic labels they could fracture the web into many non-interoperable pieces, as a result semantic labels through microformats need to be created in a controlled and standardised manner.