Friday Jan 18, 2013

Refresh Problems using Adaptive Bindings

In a previous article (Towards Ultra-Reusability for ADF - Adaptive Bindings)  I discussed how ADF Data Binding can be a lot more flexible that you would think due to the neat trick of being able to use expression language within the PageDef file to create bind sources that  can be switched at runtime.

As it happens my good buddy Frank Nimphius picked up the technique to use on a particular  project and hit a slight problem. If you change the results of the EL used in the binding - for example, you switch the base VO from Departments to Employees, things don't get refreshed correctly.  In fact what you see is that any attribute names that happen to match between the old and the new source will be correctly populated with the new data but the actual list of attributes will not be refreshed. The effect is that if you were using one of these bindings to populate a table, the "shape" of the table, in terms of its columns, would not change. 

No worries though, given that Frank is a clever chap he worked out the correct way to address this which is to simply call clearForRecreate() on the iterator binding.

 BindingContext bctx = BindingContext.getCurrent();
 BindingContainer bindings = bctx.getCurrentBindingsEntry();
 DCIteratorBinding iter = (DCIteratorBinding)
 bindings.get("TableSourceIterator");
 iter.clearForRecreate();

Thanks Frank! 

Tuesday Jan 10, 2012

Ever Wondered how uncommittedDataWarning Works?

You may have come across the uncommittedDataWarning attribute on the <af:document> tag.  With this attribute switched to "on" the framework will pop up a dialog like this when you try and navigate away from the page with the possibility of loosing the change: 

Browser dialog for unsaved changes

 What if you wanted to check yourself, in a programmable way or from an EL expression, against the same data so that you could, for example, popup your own dialog or mark a "save" menu item as enabled. Is it possible? Well yes of course and really very neat. Here's the code snippet (thanks to Dave S. who gave me this hint ages ago ) 

 ViewPortContext rootViewPort = ControllerContext.getInstance().getCurrentRootViewPort();
 boolean uncommittedChanges = rootViewPort.isDataDirty();

This simple snippet will query all the transactional data controls on the page and in all regions in the page for their dirty status and deiver a simple boolean result to you.

Wednesday Apr 27, 2011

Integrating ADF and Servlets

Inspired by a recent (OK not so recent but I’ve been busy)  OTN Code Harvest article from Frank Nimphius and prompted by a specific customer question along the same lines I’ve put together a simple example project that demonstrates the technique in a very simple manner. Frank is discussing the common case of reusing ADF Business Components Application Module context, however, my sample is a little simpler and is just using a humble POJO for simplicity.

You can download the sample workspace from here: Sharing ADF context with a Servlet.

This sample is based on JDeveloper / ADF 11.1.1.4 (Fusion Middleware Patchset 3) but should upgrade to newer 11.1.1.n versions without a problem. There are no database dependencies.

To try it out, just unzip the sample, make and run index.jspx in the ViewController project.

This code demonstrates how a Servlet within an application can share the same data control context (frame) as the underlying UI pages and Task Flows within that application.
This approach is useful when you are creating integrated applications where servlets are leveraged to add functionality to the application such as AJAX calls or email generation

Notes

  1. The Servlet path is mapped to the same pageDef as the required ADF content in the DataBinding.cpx file
  2. The Servlet is registered with the ADF Binding filter in the web.xml file
  3. The "calling" page (or taskflow) will temporarily store the current Data Control Frame name on the session
  4. The servlet will retrieve the data control frame name and use that to access the binding that is required in the correct context
About

Hawaii, Yes! Duncan has been around Oracle technology way too long but occasionally has interesting things to say. He works in the Development Tools Division at Oracle, but you guessed that right? In his spare time he contributes to the Hudson CI Server Project at Eclipse
Follow DuncanMills on Twitter

Note that comments on this blog are moderated so (1) There may be a delay before it gets published (2) I reserve the right to ignore silly questions and comment spam is not tolerated - it gets deleted so don't even bother, we all have better things to do with our lives.
However, don't be put off, I want to hear what you have to say!

Search

Archives
« July 2014
MonTueWedThuFriSatSun
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
   
       
Today