Batching the Output of a WODisplayGroup
Description
One of the most useful features of a WODisplayGroup is its capacity to display its output in fixed-sized batches. Users can navigate to the previous batch or the next batch using hyperlinks or buttons. Batching reduces the amount of data transmitted to the user's browser and makes the output more managable.
If you create the WODisplayGroup using Project Builder's Wizard, the default batch size is 10. Thus if there are one hundred objects to display, displayedObjects returns only the first ten of those objects when the page is generated. If displayNextBatch is invoked, displayedObjects is updated to contain the next ten objects, and the page is regenerated.
You use displayNextBatch and displayPreviousBatch to move back and forth through the displayed objects. These methods can be bound directly to the action attributes of hyperlinks or buttons.
The setNumberOfObjectsPerBatch method changes the batch size. You can also change batch size using WebObjects Builder's display group configuration panel, which is accessed by double-clicking the display group in the object browser.
See Also
- Creating a WODisplayGroup
- Setting a WODisplayGroup's Fetch Specification Programmatically
- Manipulating Selections in a WODisplayGroup
- WODisplayGroup class specification in the WebObjects Framework Reference .
© 1999 Apple Computer, Inc.
