eu.erasmuswithoutpaper.registryclient

Interface CatalogueFetcher

All Known Implementing Classes:

DefaultCatalogueFetcher

public interface CatalogueFetcher

Provides a raw <catalogue> HTTP response, as specified in the Registry API.

Classes implementing this interface are able to acquire the catalogue response from the Registry Service. We provide a default implementation of this interface called DefaultCatalogueFetcher, but sometimes you might want to provide your own implementation, for example when running unit tests.

Since:

1.0.0

See Also:

DefaultCatalogueFetcher, ClientImplOptions.setCatalogueFetcher(CatalogueFetcher)

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	CatalogueFetcher.Http200RegistryResponse Represents a HTTP 200 Registry catalogue response.
static class	CatalogueFetcher.Http304RegistryResponse Represents a HTTP 304 Registry catalogue response.
static class	CatalogueFetcher.RegistryResponse A common base for both Registry catalogue responses.

Method Summary

Modifier and Type	Method and Description
CatalogueFetcher.RegistryResponse	fetchCatalogue(String etag) Fetch the catalogue from the Registry Service, or confirm that it didn't change.

Method Detail

fetchCatalogue

CatalogueFetcher.RegistryResponse fetchCatalogue(String etag)
                                          throws IOException

Fetch the catalogue from the Registry Service, or confirm that it didn't change.

Implementations are strongly advised to include the attached ETag value in their If-None-Match HTTP header when making the request to the Registry API. ClientImpl is interested in just two types of Registry API responses:

• If HTTP 200 is received, then this method must return an CatalogueFetcher.Http200RegistryResponse object.
• If HTTP 304 is received, then this method must return an CatalogueFetcher.Http304RegistryResponse object.
• If any other type of response is received from the Registry API, or the Registry API cannot be contacted, then this method must throw an IOException.

Parameters:

etag - String or null. If not null, then it should contain the ETag value to be used in the If-None-Match request header (the ETag representing the version of the catalogue which we currently possess). If null, then this method will not use the If-None-Match header (and will therefore be expected to return an CatalogueFetcher.Http200RegistryResponse).

Returns:

Either CatalogueFetcher.Http200RegistryResponse or CatalogueFetcher.Http304RegistryResponse object.

Throws:

IOException - if Registry API could not be contacted, or it has responded with a HTTP status different than 200 and 304.