Support paging and sorting for custom queries [DATAGRAPH-653]

[spring-projects-issues]

Vince Bickers opened DATAGRAPH-653 and commented

Please see:

http://stackoverflow.com/questions/30624435/paging-and-sorting-in-spring-data-neo4j-4/30625554

---

Affects: 4.0 M1, 4.0 RC1

Issue Links:

• DATACMNS-878 Crash when defining a paged repository method
  ("is depended on by")

Referenced from: commits 8b76138

6 votes, 13 watchers

[spring-projects-issues]

Luanne Misquitta commented

PR raised neo4j/neo4j-ogm#19
This introduces the support for paging and sorting to the OGM

[spring-projects-issues]

Yang commented

Any update on this?

[spring-projects-issues]

Luanne Misquitta commented

@Yang, not much. We'll update it when it's been targeted to a specific release

[spring-projects-issues]

Sharif El-Borgi commented

@Luanne, is there any updates on this? Has this been targeted for a release?

[spring-projects-issues]

Luanne Misquitta commented

@Sharif not targeted for the next release. Will update this thread when we're sure about the release it is going in to

[spring-projects-issues]

Sharif El-Borgi commented

Hi Luanne,

My apologies to ask again, this is quite an urgent problem for us.

As we have an issue where loadAll on the session with Pagination doesnt calculate the counts correctly and of course in certain cases causes no results when we know logically there should be.

But because the calculations are incorrect - this as you can imagine is quite an issue.

Any news welcome ...

Hope to hear from you

Sharif

[spring-projects-issues]

Luanne Misquitta commented

Hi Sharif,

We've got a planning meeting next week- we'll update this issue post that.
This issue talks about paging and sorting on custom queries i.e. @Query but it looks like you have a question about loadAll? If they're not the same can you open a separate issue for it and we'll discuss that as well

Thanks
Luanne

[spring-projects-issues]

Luanne Misquitta commented

Hi Sharif,

We're targeting 4.1 GA for paging and sorting of custom queries

[spring-projects-issues]

John Deverall commented

@Sharif, it may not help you, but until this feature is complete, we're filling the gap with this.

public class PageHack {

	public static <T> List<T> pageHack(List<T> dtoList, int pageNumber, int pageSize) { 

		// start position of the page within our collection is the page number * page size
		int fromIndex = pageNumber * pageSize;
		
		if (fromIndex >= dtoList.size()) { 
			return new ArrayList<T>();
		}

		int toIndex = fromIndex + pageSize;
		
		if (toIndex >= dtoList.size()) { 
			toIndex = dtoList.size();
		}
		
		return dtoList.subList(fromIndex, toIndex);
	}	
}

We use it in our controller classes to get a page worth of resources from the total collection along the lines of:

List<MyResource> myResources = PageHack.pageHack(myResources, pageable.getPageNumber(), pageable.getPageSize());
Page<MyResource> page = new PageImpl<MyResource>(myResources, pageable, totalCollectionFromDatabase.size());

Obviously there is a performance overhead to this but we're in a position where we can wear it in the meantime until this feature is complete. Hope this helps

[spring-projects-issues]

Luanne Misquitta commented

Sorting and paging now supported for custom queries. If exact counts are required in pages, a countQuery must be supplied, otherwise, an estimated count is used

[spring-projects-issues]

Sivaprasad Sreenivasan commented

@Luanne Misquitta Is there an example on how to use this?

[mhmtszr]

Pagination is working but ORDER BY $sortBy is not working I tried different types of queries but I couldn't find a way to sort the custom query dynamically.