Wednesday Sep 12, 2012

Iterating selected rows in an ADF Faces table

In OTN Harvest May 2012; http://www.oracle.com/technetwork/developer-tools/adf/learnmore/may2012-otn-harvest-1652358.pdf I wrote about "Common mistake when iterating <af:table> rows". In this entry I showed code to access the row associated with a selected table row from the binding layer to avoid the problem of having to programmatically change the selected table row.

As it turns out, my solution only worked fro selected table rows that are in the current iterator query range. So here's a solution that works for all ranges

public String onButtonPress() {
  RowKeySet rks = table.getSelectedRowKeys();
  Iterator it = rks.iterator();
  while (it.hasNext()) {
   List selectedRowKeyPath = (List)it.next();            
   //table is the JSF component reference created using the table's binding
   //property         
   Row row = ((JUCtrlHierNodeBinding)table.getRowData(selectedRowKeyPath)).getRow();
   System.out.println("Print Test: " + row.getAttribute(1));
  }
   return null;
}


Tuesday May 29, 2012

Common mistake when iterating rows

In a blog entry from 2010, Oracle's Jobinesh Purushothaman writes about exceptions that are getting raised after developers iterate the collection of a RichTable instance using calls to setRowKey(key).

http://jobinesh.blogspot.co.uk/2010/02/common-mistake-while-iterating-through.html

The reason for the exception is that the selected row state is change on the table without synchronization to happen with the ADF binding layer. The failure of synchronizing the table selected row state with the ADF binding layer is because no row selection event is raised on the table if the row currency is changed programmatically. In theory, if you call #{bindings.treebinding.treeModel.makeCurrent}using a method expression in EL

The failed binding synchronization is because no row selection event is fired when the selected row state is changed on the table using Java in a managed bean.

A solution to this problem could be to call #{bindings.treebinding.treeModel.makeCurrent}from a method expression in Java each time you called setRowKey(key). But, assuming the iteration of rows in a table is for aggregating numeric values or to compare two rows, do you really want to change the current row in the ADF binding layer for each row you need to access?

A better implementation for this use case in my opinion is to read the data from the ADF binding layer instead of the RichTable table instance, which then will not change the row currency at all.

RichTable table = ... get table reference ...
Iterator iter = selectedRowKeys.iterator();
CollectionModel model = (CollectionModel ) table.getValue();
JUCtrlHierBinding treeBinding = (JUCtrlHierBinding )model.getWrappedData();
if (iter != null && iter.hasNext()) {
  Object rowKey = iter.next();
  JUCtrlHierNodeBinding rowData = treeBinding.findNodeByKeyPath(rowKey);     
  //Do something here

}

Note that the reported problem in Jobinesh's blog is for ADF bound tables configured for single row selection. Still I would prefer my approach over changing the selected row state on a table.


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The Oracle JDeveloper forum ranks in the Top 5 of the most active forums on the Oracle Technology Network (OTN).



The OTN Harvest blog is a summary of selected topics posted on the OTN Oracle JDeveloper forum.



It is an effort to turn knowledge exchange into an interesting read for developers who enjoy little nuggets of wisdom





Frank Nimphius

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