com.scvngr.levelup.core.net.request.factory

Class AbstractPagingRequestFactory

java.lang.Object

com.scvngr.levelup.core.net.request.factory.AbstractRequestFactory

com.scvngr.levelup.core.net.request.factory.AbstractPagingRequestFactory

Direct Known Subclasses:

AppLocationListRequestFactory, LocationListRequestFactory

@LevelUpApi(contract=INTERNAL)
public abstract class AbstractPagingRequestFactory
extends AbstractRequestFactory

A request factory that can page through requests. This is used with endpoints that support the Link header, as noted in LinkHeaderParser. This will save the next page URL in a shared preference so that it can be resumed from that point forward.

To use, subclass and implement methods to retrieve the first page (getFirstPageRequest() ) and to construct a request for an arbitrary page from a URL (getPageRequest(Uri)). Once a page has been loaded successfully, setNextPage(Uri) should be called with the URL contained in the Link header.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	AbstractPagingRequestFactory.PageCacheRetriever Implement this to support persisting the URL that points to the next page of information.

Constructor Summary

Constructors

Constructor and Description
AbstractPagingRequestFactory(Context context, AccessTokenRetriever retriever, AbstractPagingRequestFactory.PageCacheRetriever pageCacheRetriever, String savedPageKey)

Method Summary

Modifier and Type	Method and Description
abstract AbstractRequest	getFirstPageRequest() Subclasses must implement this to construct a new request for the first page.
AbstractRequest	getNextPageRequest() Gets the next page.
protected AbstractPagingRequestFactory.PageCacheRetriever	getPageCacheRetriever()
abstract AbstractRequest	getPageRequest(Uri page) Subclasses must implement this to construct a new request for the given next page.
void	setNextPage(Uri page) Sets the next page.

Methods inherited from class com.scvngr.levelup.core.net.request.factory.AbstractRequestFactory

getAccessTokenRetriever, getContext

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractPagingRequestFactory

public AbstractPagingRequestFactory(Context context,
                                    AccessTokenRetriever retriever,
                                    AbstractPagingRequestFactory.PageCacheRetriever pageCacheRetriever,
                                    String savedPageKey)

Parameters:

context - the context.

retriever - an access token retriever.

pageCacheRetriever - a page cache retriever.

savedPageKey - a key that's unique for the endpoint that this request factory is for. This should be full namespaced to ensure its uniqueness.

Method Detail

getFirstPageRequest

public abstract AbstractRequest getFirstPageRequest()

Subclasses must implement this to construct a new request for the first page. This is usually just a request to the endpoint.

Returns:

a request for the first page.

getNextPageRequest

public final AbstractRequest getNextPageRequest()

Gets the next page. If no pages have been loaded before, this returns the result of getFirstPageRequest(), otherwise it loads a request for the next page with getPageRequest(Uri).

This must not be called from the UI thread.

Returns:

a request for the next page that should be loaded.

getPageRequest

public abstract AbstractRequest getPageRequest(Uri page)

Subclasses must implement this to construct a new request for the given next page.

Parameters:

page - the URL of the next page that should be loaded.

Returns:

a request for the next page or null if there is an error.

setNextPage

public final void setNextPage(Uri page)

Sets the next page. This is the URL returned in the Link header for each page that has been successfully loaded into cache.

This may be called from the UI thread.

Parameters:

page - the URL as returned by the Link header of the response or null to clear.

getPageCacheRetriever

protected AbstractPagingRequestFactory.PageCacheRetriever getPageCacheRetriever()

Returns:

the page cache retriever.