[aerogear-dev] Client Paging Strawman

[Douglas Campos]

I'm not a fan of those PageContext objects (remembers me of some wild-ass ThreadLocals leaking all over)

My proposal for the paging aware APIs would be something like this:

public interface PagedResult<T> {
 
    List<T> next();
 
    List<T> prev();
 
    List<T> page(int offset, int limit);
 
}

and the Async counterpart

public interface AsyncPagedResult<T> {
 
    void next(Callback<List<T>> callback);
 
    void prev(Callback<List<T>> callback);
 
    void page(int offset, int limit, Callback<List<T>> callback);
    
    public static interface Callback<U> {
        public void onResult(U result);
    }
}

I don't like the idea of having a companion object for holding the pagination state.

Thoughts?

-- qmx 

On 15/01/2013, at 08:37, Matthias Wessendorf <matzew at apache.org> wrote:

> Hi Summers,
> 
>  
> https://gist.github.com/4532661
> 
> That is a way to do paging which keeps Pipes immutable, uses readWithFilter, and doesn't impose any (for convenient definitions of any) bookkeeping on the developer.
> 
> 
> from your Andorid gist:
> 
> A) Once the response has been received, the Pipe implementation will return a List of objects. If this List instance is passed to Pipe.getPageContext the appropriate PageContext will be returned
> 
> Note: There is no 'return' - the readWithFilter is void, instead a Callback is invoked (onSuccess(list)), see Pipe.java
> 
> B) The developer will receive from readWithFilter() a List of object. If she passes this list into Pipe.getPageContext(List result) she will receive the PageContext associated with this result.
> 
> Do you mean like:
> 
> ...
> myPipe.readWithFilter(filter, new Callback<List<Data>>() {
> 
>     
> @Override
> 
>     
> public void onSuccess(List<Data> data) {
> 
> 
>         
> // get the PageContext:
> 
>     
> PageContext ctx = myPipe.getPageContext(data);
> 
>         
> ...
> 
>     
> }
> 
> 
>     
> @Override
> 
>     
> public void onFailure(Exception e) {
> 
>     
> }
> });
> Not sure about that.....
> 
> But for iOS I am thinking about passing in the PageContext into the closure/block of the readWithFilter, like:
> 
> -(void) readWithFilter:(void (^)(id<AGFilterConfig> config)) config
> 
>                
> success:(void (^)(id listOfObjects, id pageContext))success
> 
>                
> failure:(void (^)(NSError *error))failure;
> A usage would look like:
> 
>     [pipe readWithFilter:^(id<AGFilterConfig> config) {
> 
>         
> // set the filter args and override the given defaults
> 
>     
> } success:^(id listOfObjects, id pageContext) {
> 
>         
> // work with the listOfObjects reponse.
> 
>         
> // for paging/query info, access the given pagecontext,
> 
>         
> // of the CURRENT request
> 
>         
> ...
> 
>     
> } failure:^(NSError *error) {
> 
>         
> // handle errorz
> 
>     
> }];
> Any thoughts ?
> 
> Not sure I like (or understand) the Pipe.getPageContext(List result) call. Current mindset is that thePageContext just (and only) belongs to the previous (executed) request... Not sure I want to support something like
> 
> // first call:
> List<SomeType> first;
> myPipe.readWithFilter(.....) // set first inside of callback
> ...
> // second call:
> List<SomeType> second;
> myPipe.readWithFilter(.....) // set second inside of callback
> ...
> // third call:
> List<SomeType> third;
> myPipe.readWithFilter(.....) // set third inside of callback
> ...
> 
> 
> 
> 
> /// A BIT LATER ....:
> myPipe.getPageContext(first);
>  
> 
> I am not sure if that (myPipe.getPageContext(first);) is really desired (or would even easily work, as it would need to store the "metadata")..... 
> 
> 
> Perhaps I am just wrong.
> 
> 
> -- 
> Matthias Wessendorf 
> 
> blog: http://matthiaswessendorf.wordpress.com/
> sessions: http://www.slideshare.net/mwessendorf
> twitter: http://twitter.com/mwessendorf _______________________________________________
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