Oracle SOA Suite Developer’s Guide

Service-Oriented Architecture (SOA) is not about technology, although technology is used to implement it. The principles of reliability and accommodating unexpected changes at a manageable cost can be applied equally in any programming language. However, as with most things in life, not just software development, it is easiest to use a model that is supported by tools and inter-operable (the ability of two or more systems or components to exchange information and to use the information that has been exchanged). A standards-based Service-Oriented Architecture (SOA), is such a model that enables IT infrastructure is continuously adapted to keep up with the pace of business change.

Matt Wright and Antony Reynolds have just published a book Oracle SOA Suite Developer’s Guide that provides a best practice guide to using the Oracle SOA Suite for building a real world applications. This book bridges the gap between SOA theory and the Oracle SOA Suite Manuals and is based on the experience of implementing SOA across a number of organisations in EMEA and APAC. It is a book of three parts. The first section of the book provides detailed coverage of all components of the SOA Suite, namely OSB, BPEL, Rule, BAM and OWSM. The second section addresses the common question: “What is the best way to combine / use all of these different components to implement a real-world SOA solution?”. Using a working example of an online auction site, it leads you through key SOA design considerations in implementing a robust solution that is designed for change. Though the examples in the book are based on Oracle SOA Suite 10.1.3.4 the book will still be extremely useful for anyone using 11g. The final section addresses non-functional considerations and covers the packaging, deployment, and testing of SOA applications; it then details how to use Web Service Manager to secure and administer SOA applications.

I’m sure this book will continue to be relevant in years to come to. Unlike other technical books, this one does more than just explain “how” to do A, B, and C, but goes to great lengths to explain the concepts. As a software developer it is vital to understand why we were doing what we were doing, so that we know which principles to apply in different situations.

Offshoring / Outsourcing with scrum

Clearly the use of scrum with distributed teams is something a lot of people are talking about right now. After last months article on scrum and offshoring, focusing mostly on communication challenges, I have noticed a number of blog postings on the subject. David Myers (a consultant at London based Charteris), in his article on Scrum and Outsourcing, goes into great detail about the challenges with distributed teams. For me, the key points are that basic agile practices of communication, meaningful documentation and continuous integration removes some of the hurdles. However, the manner that the standards / approaches applied have to suit the team.

I’ll leave the last word to David…

For me the most important consideration when employing Scrum with offshore resources is that it should not be employed without modifying and/or tuning some of the practices to be more suited to working with geographically split teams. This tweaking (or lack thereof) can have a fundamental effect on the end result.

Does “scrum” work in offshoring?

A question posed a few months back on stackoverflow on scrum and offshoring got a number of mixed responses. Many state that scrum does not work with remote teams. There may be a number of factors to scrum not working, which has very little to do with scrum in the first place. Some teams are not suitable to scrum, or rather, the individuals on the team are not suitable. Scrum requires a change in mindset, to be proactive, not be willing to fail, and be willing to be honest.

The time difference does appear to be the biggest obstacle. Many of the other issues, such as cultural differences, can be resolved, or at least mitigated, with direct communication. Direct communication is hampered when remote teams work in different time zones.

Flexibility is required from the team members in all locations. It may suit some members of the team to start early and leave early so that their working hours overlap with some of the others. This has to be sustainable. The team members that come in early should not be the ones who regularly leave late. If this occurs, there is a problem with resource bottlenecking. What would happen to the team when this member goes on holidays? A meeting that involves the whole team is often not required if the team members take the responsibility to communicate to each other. I have found instant messaging to be quite useful in this regard. When having a discussion with some team members in a chat room, the messages can be saved and posted to a wiki or emailed to the rest of the team. This also helps to clear up confusion over what was said during a telephone conversation.

Note that I only refer to one team. Referring to a group of team members by their location may reinforce the differences between the groups. For example, rather that referring to team members as the ‘San Jose Team’ or the ‘Palo Alto Team’, try ‘The team members in San Jose’ or ‘The team members in Palo Alto’. This suitable change emphasises that the team is one unit, just distributed.

Getting requestor’s IP address through Oracle WSM

Oracle Web Services Manager (OWSM – some people pronounce it as ‘Awesome’) plays an important roll in Oracle’s contribution to SOA governance. Put simply, it brings better control and visibility over how, when and by whom, web services are invoked. OWSM, which is a key product in the Oracle SOA Suite, was voted one of the best security solutions by SYS-CON Media, the world’s leading i-technology media and events company in it’s 2007 SOAWorld Readers’ Choice Awards.

Apart from the predefined policies, OWSM provides an extensibility point to define a custom policy step that can be executed as part of the request or response pipeline. There is an Oracle by Example (OBE) tutorial available that provides details for creating a custom step. The custom step authenticates the user against a fixed set of username/password credentials configured in the policy step pipeline.

You can go one step further and check IP address of the requesting client by accessing the HttpServletRequest in the MessageContext in the execute operation of your custom step code.

import com.cfluent.pipelineengine.container.MessageContext;
…
((HttpServletRequest) ((MessageContext) messageContext).getProperty(“javax.servlet.request”)).getRemoteHost()

Remember that if there are proxies or NAT address translations between the requester and the provider you won’t know the real source IP. Clearly this only works for HTTP based requests. However, a similar approach could be used for JMS.

It is worth mentioning Vikas Jain’s Web Services Security blog which is a treasure trove of useful information on OWSM.

Best in class for digital camera advice

Now that I’m doing more Flex development I’m branching out into all sorts of wonderful animations, charts, and countless ways to navigate through and manipulate images. So, after years of ‘server side’ I’m discovering pictures! I’m also discovering that lot’s of people I know include photography amongst their list of hobbies. Some of them go even further by trying to make some money out of it, and they do, sometimes. Of course it doesn’t necessarily always cover the cost of the equipment. Or at least I thought so until I started noticing that not everyone is using a hi-tech superduper gizmo and gadgets to take good photos. Quite a few use cameras from the Canon PowerShot range because they are fast, but not ridiculously expensive.

After a while you begin to notice that they actually have more than one camera, quite a few actually. So how do they choose which is right one? Many are using BestInClass to research digital cameras in particular. Using the unbiased recommendations of qualified hobbyists and professionals, and a clever set of simple search criteria, this simple site is a good place to start when looking for best in class advice on digital cameras.