1

CSSE 477 – SOA

Architectures

Steve Chenoweth

Thursday, 11/3/11

Week 9, Day 3

Right – Web services techniques for XML-based integrated systems. From http://www.emeraldinsight.com/journals.htm?articleid=862014&show=html.

2

Today

• SOA - Designing architectures and services.• Turn-in the in-class SOA intro programming

exercise from Tuesday.

• Tomorrow –– A day to work on your presentations for week 10.– Steve may be out of town – I’ll let you know.

3

Typical SOA app in action

The two circled apps – we want to make use of SOA for (1)Accessing outside services shown at right, and(2)Allowing customer organization’s apps to access us.

You

4

What about the customer?

• If we also could get their order placement app within our own shop, that would be even better!

• How likely?

• So,

5

How to make it all work!?

• Requires a strategy to integrate our systems with everyone else’s.

• Even though they are created elsewhere.• SOA is a key to making this happen,

because of growing acceptance and suitability toward this end.

• Architects and management need to make “governance” decisions with systems developments.

6

Setting up shared services

7

Where we are a service consumer

• We worry about available services’ functionality.

• They could disappear on us!

• May not be “semantically correct” for us.– No standard data models.– E.g., What’s in a “customer order”?

• Those offered by competing organizations could be different, so hard to switch.

• And there’s that pesky end-to-end testing!

8

And what about the other side?

9

Where we are a service developer

• If we don’t understand customer requirements, we could flop as a provider!

• And, we’re in a classic, perfect open market…– Where everyone knows about

every competitor, their prices, etc.

• Translating legacy systems to SOA always has issues.– Like converting to web-looking

data types.

• Need to be able to live up to SLA’s – Service Level Agreements.

10

Or we’re in the middle…

11

For the infrastructure developer

• “Responsible” for end-to-end performance.

• How do you handle changes in standards and products you support?

• The level of training (e.g., for the other organizations using your tools) can be underestimated!

• Granularity decisions to make!

12

Granularity…

13

The internal/external question

14

Requirements anticipation…

15

Transaction management responsibilities

16

Transaction management responsibilities – cntd

17

Transaction management responsibilities – cntd

18

Summary – SOA architectures

• Affect three different development groups:– Service consumers (programmers)– Service developers– Infrastructure developers

• The more distributed these are, the greater the global consequences.

19

Additional resources

• http://servicerepository.com/ service providers• http://webservicex.net web services by category• http://soapatterns.org/ patterns for web service

development• http://ws-i.org/ OASIS, the web services

interoperability org• http://xmethods.com publicly available services• http://webservices.seekda.com ditto• http://free-web-services.com/ free ones