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Re: [eclipselink-users] Best way to support case insensitive alphanumeric sorting..
I am assuming you are using the DescriptorCustomizer suggested below. (Here's some doc: http://www.eclipse.org/eclipselink/documentation/2.5/jpa/extensions/a_customizer.htm#CHDCCDGC) If that is not the case, let me know.
When you are in the DescriptorCustomizer's customize method, you will be given an instance of a descriptor. From the descriptor, you can operate on mappings. I provided code earlier to alter the ordering of your OneToMany. 

>                  OneToManyMapping oneToManyMapping =


(OneToOneMapping)descriptor.__getMappingForAttributeName("__attributeName");
                  ExpressionBuilder builder =
              oneToManyMapping.__getSelectionQuery().__getExpressionBuilder();
If you want to make some decisions based on the postalCode mapping, you can get it roughly like this: 

  ClassDescriptor referenceDescriptor = oneToManyMapping.getReferenceDescriptor();
DirectToFieldMapping dtfMapping = (DirectToFieldMapping)referenceDescriptor.getMappingForAttributeName("postalCode"); 

  Class attributeClassification = dtfMapping.getAttributeClassification();
// attributeClassification will be a java class, you can put some condtional logic here to help you build the expression. The expression could be something like this:
Expression orderExpression = builder.get("postalCode").__toLowerCase().ascending(); 
  oneToManyMapping.__getSelectionQuery().__addOrdering(orderExpression);


On 11/06/2013 3:48 PM, vaidya nathan wrote:

Thanx Tom,

I am not very conversant with the descriptor. How do i initialize that ..

Tried
   RelationalDescriptor descriptor = new RelationalDescriptor();
   descriptor.setJavaClass(eb.getQueryClass()); // eb is the expressionbuilder
   descriptor.setPrimaryKeyFieldName("ID");
   descriptor.setTableName(<<Table name>>);

    DirectToFieldMapping dtfMapping = (DirectToFieldMapping)
descriptor.getMappingForAttributeName(order);
    Class mappingType = dtfMapping.getAttributeClassification();

Here the descriptor is always coming as null .. i tried going through the
samples and documentation but couldnt find how to initialize the mappings . Can
you please point me / let me know how i need to populate the mappings. Also i am
using RelationalDescriptory .. is that the right descriptor.

Thx a lot
Vaidya



On Tue, Jun 11, 2013 at 12:29 PM, Tom Ware <tom.ware@xxxxxxxxxx
<mailto:tom.ware@xxxxxxxxxx>> wrote:

    You can get the type from the mapping for a particular attribute like this:

    DirectToFieldMapping dtfMapping =
    descriptor.__getMappingForAttributeName(<__directAttributeName>);
    Class mappingType = dtfMapping.__getAttributeClassification();

    Notice that the type will be a java class rather than a database type.

    -Tom


    On 11/06/2013 9:45 AM, vaidya nathan wrote:

          From the documentation , I see that we cant use this for non String
        columns
        like say Numeric columns.

        For eg, if the column is a numeric , then this will not work ..

        Expression  exp = (ascending ? exp.toLowerCase().ascending() :
        exp.toLowerCase().descending()__) ;

        Is there a way in which we can get meta data information about the
        column and
        then have this sort something like

        if (column is String)
        {
        Expression  exp = (ascending ? exp.toLowerCase().ascending() :
        exp.toLowerCase().descending()__) ;
        }
        else
        {
        Expression  exp = (ascending ? exp.ascending() :  exp.descending()) ;
        }


        Or is there any other way in which we can do this. If possible please
        furnish me
        some  sample codes too or point me to some samples where we are doing this .

        Also Dennis you said that didn't work .  Can you elaborate please? What
        issues
        did you have ?

        Thx for all your response
        Vaidya


        On Thu, Jun 6, 2013 at 9:11 AM, Dennis Fuglsang
        <dennis.fuglsang@xxxxxxxxxx <mailto:dennis.fuglsang@xxxxxxxxxx>
        <mailto:dennis.fuglsang@__oracle.com
        <mailto:dennis.fuglsang@xxxxxxxxxx>>> wrote:

             I had a similar requirement and initially tried using the UPPER
        operator in
             the ORDER BY clause but that did not work for me.  For example:
        "SELECT
             a.ID, a.name <http://a.name> <http://a.name> FROM Table a ORDER BY
        UPPER(a.name <http://a.name>
             <http://a.name>)"


             What did work for me was specifying an upper-cased form of the
        column to
             sort on in the SELECT clause.   For example:   "SELECT a.ID, a.name
        <http://a.name>
             <http://a.name>, UPPER(a.name <http://a.name> <http://a.name>) AS
        name_order FROM Table a

             ORDER BY name_order"



             -----Original Message-----
             From: Tom Ware
             Sent: Thursday, June 06, 2013 9:05 AM
             To: eclipselink-users@xxxxxxxxxxx
        <mailto:eclipselink-users@xxxxxxxxxxx>
        <mailto:eclipselink-users@__eclipse.org
        <mailto:eclipselink-users@xxxxxxxxxxx>>
             Subject: Re: [eclipselink-users] Best way to support case insensitive
             alphanumeric sorting..

             EclipseLink provides toUpperCase() and toLowerCase() expressions
        and JPA
             provides UPPER and LOWER operators.  For queries I expect you could use
             those operators in the ORDER BY part of your query to sort.

             If you are talking about a mapping, you could use an EclipseLink
             DescriptorCustomizer to add ordering by an EclipseLink expression
        to the
             selection query.  Roughly:

                 OneToManyMapping oneToManyMapping =

        (OneToOneMapping)descriptor.__getMappingForAttributeName("__attributeName");
                 ExpressionBuilder builder =
             oneToManyMapping.__getSelectionQuery().__getExpressionBuilder();
                 Expression orderExpression =
             builder.get("postalCode").__toLowerCase().ascending();

        oneToManyMapping.__getSelectionQuery().__addOrdering(orderExpression);

             -Tom
             On 05/06/2013 11:54 AM, vaidya nathan wrote:
              > Hi,
              >
              > What is the best way to support case insensitive alphanumeric
        sorting
              > using jpa2 and eclipselink ? An example of what i would like to
              > achieve is to sort on something similiar to the canada zips
        which could
             be alphanumeric..
              >
              > We are using Eclipselinks ReadAllQuery and Expression language to
              > build our queries and the queries that we have so far is like this..
              >
              > SELECT * FROM
              > (SELECT a.*, ROWNUM rnum  FROM
              > (SELECT DISTINCT t1.ID AS a1,<colname>
              >    FROM <Table>  ORDER BY t0.<colname> ASC) a WHERE ROWNUM <= ?)
        WHERE
             rnum > ?
              > )a
              >
              >
              > Thx
              >
              >
              >
              >
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