Can you pass the Processor (or whatever it's really called) into the object
that implements the RowHandler?
So your ItemProvider would have a method like:
public void processAllItems (Processor processor) {
ItemRowHandler rowHandler = new ItemRowHandler();
rowHandler.setProcessor (processor);
sqlMap.queryWithRowHandler ("getAllItems", rowHandler);
}
Then your RowHandler would look like:
public class ItemRowHandler implement RowHandler {
private Processor processor;
public void handleRow(Object valueObject) {
Item i = (Item) valueObject;
processor.process(i);
}
}
Cheers,
Chris
On 10/3/07 4:14 PM, "[EMAIL PROTECTED]"
<[EMAIL PROTECTED]> wrote:
> My problem with RowHandler is that iBATIS controls the iteration. I just say
>
> sqlMap.queryWithRowHandler ("getAllItems", rowHandler);
>
> and all items get processed by the rowHandler.
>
> But in my case I need to make iBATIS return items one-by-one when it is asked
> to do so because the framework controls the iteration.
> This is a very simplified basic logic of the framework:
>
> while (itemProvider.hasNext()) {
> Object item = itemProvider.next();
> process(item);
> }
>
>
>
> -----Original Message-----
> From: Christopher Lamey [mailto:[EMAIL PROTECTED]
> Sent: Wed 10/3/2007 11:55 PM
> To: [email protected]
> Subject: Re: how to map huge resultsets?
>
> Hmm...I don't see how having an external framework prevents you from using a
> RowHandler. Your item provider could implement the RowHandler interface and
> the external code wouldn't know or care about it. Or your item provider
> could wrap something that does implement RowHandler so the external code
> doesn't know it exists. The main point is that you can pull mapped objects
> on a row by row basis from the database.
>
> How is a RowHandler different that what you were describing in your first
> mail?
>
> On 10/3/07 3:33 PM, "[EMAIL PROTECTED]"
> <[EMAIL PROTECTED]> wrote:
>
>>
>> Thanks for your reply.
>>
>> I can't use the rowhandler callback because the iteration is external to
>> iBATIS. In my case a batch framework iteratively asks for an item and
>> processes it - and I am trying to implement an iBATIS item provider (I
>> realize
>> now I should have explained this in the initial post).
>>
>> Robert
>>
>>
>> -----Original Message-----
>> From: Christopher Lamey [mailto:[EMAIL PROTECTED]
>> Sent: Wed 10/3/2007 11:06 PM
>> To: [email protected]
>> Subject: Re: how to map huge resultsets?
>>
>> Hello,
>>
>> You should take a look at the RowHandler interface and the
>> queryWithRowHandler calls in SqlMapClient (page 61 of the pdf). Basically,
>> the RowHandler gets invoked for every row returned rather than mapping all
>> the rows into objects in a collection.
>>
>> Cheers,
>> Chris
>>
>>
>> On 10/3/07 2:37 PM, "[EMAIL PROTECTED]"
>> <[EMAIL PROTECTED]> wrote:
>>
>>> Hello,
>>>
>>> I am wondering whether it possible to implement the following scenario with
>>> iBATIS:
>>>
>>> 1. run an iBATIS-managed select
>>> 2. get a scrollable result set instead of a list of mapped objects
>>> 3. manually scroll the result set and ask iBATIS for object corresponding
>>> to current row
>>>
>>> Hibernate provides this possibility
>>> (http://www.hibernate.org/hib_docs/reference/en/html/batch.html) so I
>>> thought
>>> it would be feasible with iBATIS too, but I couldn't figure out a way. The
>>> motivation is a batch scenario where the select returns a huge number of
>>> rows
>>> so all mapped objects can't be loaded into memory at once.
>>>
>>> The iBATIS way I am aware of is to use queryForList(String statementName,
>>> int
>>> skipResults, int maxResults), but this means querying the database
>>> (TOTAL_NUMBER_OF_ROWS / maxResults) times.
>>>
>>> Can somebody give advice about pros & cons of the two approaches?
>>>
>>> Thanks
>>> Robert
>>>
>>>
>>> This message is for the designated recipient only and may contain
>>> privileged,
>>> proprietary, or otherwise private information. If you have received it in
>>> error, please notify the sender immediately and delete the original. Any
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>>
>>
>>
>>
>> This message is for the designated recipient only and may contain privileged,
>> proprietary, or otherwise private information. If you have received it in
>> error, please notify the sender immediately and delete the original. Any
>> other use of the email by you is prohibited.
>
>
>
>
> This message is for the designated recipient only and may contain privileged,
> proprietary, or otherwise private information. If you have received it in
> error, please notify the sender immediately and delete the original. Any
> other use of the email by you is prohibited.
