Architect Consultant blog

The SOA Patterns of Thomas Erl contains a great pool of patterns that can be usefull for your SOA implementation. I want to use it within a project and especially the Service Layering Pattern . I expose Services always through an ESB. The next scenario puzzled me to introduce two or just one Service : 1) I have an Employee Entity ( Common Data Model ) 2) I have a TelephoneGuide (also a business entity?) that contains information about Employees 3) The telephone data is stored within a database I encapsulated the database through a webservice (I implemented it with OpenJPA because we use ALSB) Next I had two options which I will describe: Option 1 Expose the database webservice as a separate Service, because it is an Application/Data/Utility Service. This Service does not contain CDM data but data that is more close to the database tables data. Expose another Service that uses the Employee CDM entity and this is the TelephoneGuide Business Service. Option 2 Only expose ...

There has been a lot written and discussed about how to do Service versioning. On LinkedIn there is a nice discussion about the WSDL versioning (read here ). Also on InfoQ there is a nice article. I like the strategy in which a minor and major version is used. A minor change is backwards compatible and only updates the documentation element within the WSDL. A major change, also changes the namespace (http://.../v2). The following structure within the OSB can help to implement this strategy. The advantages of this structure are: * The different versions are nicely seperated and can be governed and maintained seperatly. Instead of having only one proxy for all versions and doing some content based routing. * The two versionings can live together and in case the old version is deprecated the proxy can be deleted. This way "old" consumers do not have to migrate in case a major update is published, so they have the time to plan it.

I was wondering what kind of protocols/mechanisms/standards are used to establish reliable Services? Just to get started: * HTTP But this is by definition not reliable so some extra mechanisms are needed on API level. * JMS (Queues or Topics)? Is reliable but only used within Java technology. I like the Topic idea so that other components can listen on the Service entrance. * WS-ReliableMessaging It's a standard defined on top of SOAP, but which tools, platforms already use it? * Other? I am curious in your experiences!

Just like Design Patterns, Enterprise Integration Patterns and Architecture Patterns, Thomas Erl comes with a SOA Design Pattern book. InfoQ has an interview with him: read interview He states that a SOA patterns is something different than a webservice patterns. SOA is about services and a webservice is a technology specific realization of a service. He also states that in fact EAI frameworks and middleware, enterprise service bus platforms, grid computing, transaction management systems, messaging queues, event-driven messaging frameworks, broker and mediation technologies were used as inspiration for the SOA patterns. He also explains his difference between service orientation and a SOA: "Service-orientation is a distinct paradigm that you apply to achieve a specific target state and a technology architecture is considered service-oriented if it has the characteristics necessary to support the application of this paradigm." Nice and clear right? I have not read the book (y...