Advantages and Disadvantages of

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3 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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Chapter 7

Advantages and Disadvantages of
Web Services


Objectives


By study of the chapter, you will be able to:

Describe what are the advantages of Web
services

Describe what are the completely new
business models of Web services

Describe what are the disadvantages of Web
services

Analyze the current issues involved in the
development of Web services

Questions and Discussion

Homework


What are the advantages of Web
services?


Interconnectivity and integration with the legacy
systems



Modifying internal operations, not outside entities


Knowing the legacy system well before the
development and deployment of the Web services


Language free


Interacting with user
-
friendly GUI


Resulting a state
-
of
-
art distributed system that
retains all the equity


What are the advantages of Web
services? (continue)

Lower operational costs



Cheaper than LAN via using the Internet


Low
-
cost EDI (Electronic Data Interchange)


Remote status reports through the Internet


Remote system management and troubleshooting


Dynamic routing of service people via PDAs

Lower software development cost


Empower of Code
-
reusable


Reducing of Language barrier


Following W3C (World Wild Web Consortium)
rules

What are the advantages of Web
services? (continue)

Faster system development


Better Web service tools interact with almost any
language you are using


Providing rapid development tools by many vendors
based on your WSDL (Web Services Description
Language)


Providing modern development tools that can also
generate Web service code from functional
descriptions





What are the advantages of Web
services? (continue)

Better interfaces with clients


Allowing tighter integration between vendors
and their customers


Providing convenience to customers by
allowing them to manage their own accounts

Better integration with external business
partners


Making easier with your business partners by
interactivity and interconnectivity without
significant alterations to either one




Describe what are the completely new
business models of Web services


A virtual enterprise will open new
opportunities for all; it makes up of several
smaller enterprises. For example:


A hotel in San Francisco booked your room,
scheduled your flight, reserved your rental car,
and sold you tickets to a NBA game, you would
be doing all of these with a virtual enterprise


A new business model of Web services can be
described as “Empty
-
seat selling” in discounting
systems, scheduling systems, and online selling
systems for the best profitability



What are the disadvantages of Web
services?

Pitfalls of Web services


Availability: not 100% available at all time


Matching requirements: “one size fits all
customers” philosophy is not easy to satisfy all
customers’ specialized requirements


Immutable interfaces: Some changed you made
may cause customers’ programs to break
because you might not know who are using your
service


What are the disadvantages of Web
services? (continue)

Performance issues


Speed: HTTP very transactional in nature will
slow down the performance


Overheat: Conversion to and from XML during
the communication process will take extra time,
especially for binary image data


Adequate choice: Too many to choose in terms
of different languages



What are the disadvantages of Web
services? (continue)


Lack of standards


The current Web services specifications and
standards are lacking in the following areas:

Security and privacy: only sending sensitive data to
Web services is allowed currently by using HTTPS
(Hyper Text transformation Protocol Secure Socket
Layer); otherwise, anything sent over the Internet can
be viewed by others

Authentication: “Who is contacting me?” is hard to know

Non
-
repudiation: communication is taking place all time

Billing and contracts: No pricing mechanism or
automatic billing system for use of the service yet




What are the disadvantages of Web
services? (continue)


Provisioning: no agreed upon the standard way to
establish user accounts to access Web services

Scalability: no mechanism to expose an existing system
such as Java Beans as Web services

Testing: decoupling of the clients from the server makes
testing of Web services challenge


Newness of Web service technology


Web services are still in the phase of maturity


Normally a new technology will be under
recognized after the four to five year mark


Many vendors who are fighting for market shares
may mislead the direction of the development


It’s hard to find qualified and experienced staff to
implement a workable solution



Questions and Discussion

Homework for Extra Points

Answer the following questions:


How can Web services improve customer
service?


If Web services have all those problems, should
we use them for production
-
level systems?


Due: Wednesday, May 18, 2005 in the class