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Showing posts from December, 2013

ADF UI with MongoDB for persistence

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The sample application (JDeveloper 12c / 12.1.2) is available here.
This is a simple ADF application whose underlying business service implementation uses MongoDB for persistence.
The application allows create & update operations on a one-to-many data model (Department-Employees)

As shown in the screenshot below, you can Create a new department and then create a few employee records. The "Save all changes" button then calls the standard ADF POJO DataControloperations that in turn delegate the persistence of these objects to the MongoDB without using any SQL.

The data is saved in a database called "hrdb"  (see class MongoDAO in the Model project) in a collection called "Departments"


The design I have used is very basic and shown below.
I have used simple POJOS extending ReflectionDBObject as my 'persistable' entities but this can be anything else (such as EclipseLink) that can support MongoDB (either programmatically or out of the box).


Setup…

Webservice interaction patterns - part 2 - Synchronous Webservice call timeouts

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Goal:For reasons of performance and more importantly, good user experience, the client application (ADF) should be able to timeout gracefully instead of hanging indefinitely (and/or potentially causing STUCK threads on the ADF server) when invoking an external 'synchronous' web service.

At runtime
When I run the application,
If I enter all fields (remember to enter a unique Employee ID, email address etc), then the 'Commit' button calls the web service as usual.

However, if I Create a new record with the FirstName field set to TIMEOUT, you will notice that you see a timeout message on the screen after around 6 seconds.
 (don't update an existing one as in the sample app, the update operation just goes directly to the DB)


If I had not performed the setup listed in the "Client setup" section below, this would have resulted in a screen that appears to hang for a long time (with STUCK threads observed on the ADF application server after a while depending on th…

Webservice interaction patterns - part 1 - very basic DML

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There are a number of ways you 'call' web services from an ADF application. The best method to choose would depend on the individual scenario.

This particular example is the most suitable option where:
- Our application is allowed to read from the database using its own business services - i.e. ADFbc (which are fairly easy to create and don't require a lot of 'plumbing' code compared to other technologies) but we need to delegate any transactional calls (such as create/update/deletes) to an external web service.

The reasons could be many: Most commonly, such business (web) services already exist with a number of person-years of effort, testing & polishing already gone into them and they already meet the requirements perfectly. So it makes perfect sense to not re-develop all that logic into ADFbc and just reuse the existing service.

What this post is not: If you have written all your business logic using ADF business components then you can expose that as a web …

JDeveloper Productivity features - run current working set

In a well designed application ('the sum of parts'), we probably divide functionality into projects. 
At any given time individual developers normally work on one or two projects, which they need to run and test quickly using the integrated weblogic server. 
For years I found the working set feature very effective for this:

http://docs.oracle.com/middleware/1212/jdev/OJDUG/gs_dev_apps.htm

Particularly note:
4.3.6 How to Manage Working Sets4.3.6.8 How to Run and Debug a Working Setbasically, using working sets, JDeveloper would only build, deploy and run projects you are specifically interested in or working on, saving you time.