[lyo-dev] eclipse/Lyo Java Client API updates for release 4.0.0

["Jim Amsden" <jamsden@xxxxxxxxxx>]

Since Apache Wink
has been retired, and the current oslc-java-client includes a large set
of Wink jar files that bloat up client implementations, we decided to remove
Wink from OSLC4J.

Unfortunately,
for the Java client, that would result in some API breaking changes. So
we decided to leave oslc-java-client alone - it and its sample applications
are unchanged in 4.0.0, and still depend on Wink. As expected, this client
works with servers that are implemented using Wink or Jersey, so there
was no need to change it.

In addition, I
created a new Java client, oslc4j-client that only depends on JAX-RS 2.0.
This client does not reference any JAX-RS implementation, leaving the choice
of the implementation up to the client applications. It also does not support
SSL or any authentication, also leaving those specifics up to the client
applications as needed. This radically simplifies the oslc4j-client, and
reduces its size, while providing the flexibility client applications need
to configure their client access.

The new OslcClient
constructor can now take a single ClientBuilder argument. The client application
creates and configures a ClientBuilder to meet their needs, and passes
in the OslcClient(ClientBuilder) constructor for subsequent use. 

I have also added
Jazz rootservices discovery methods directly to OslcClient since these
are often necessary to discover OSLC discovery URLs (and something we're
considering adding to the OSLC standards). 

As a result, there
is no longer any need for OslcClient subclasses for rootservices processing,
Jazz Form based authentication, etc.

Here's an example
of how a client application would configure, create and use an OslcClient
to access jazz-apps that use JEE Form based authentication, taken from
the oslc4j-client-samples/IECMSample.java sample application. HTTP Basic,
Digest, etc. can be handled similarly:

     
               
  //
STEP 1: Configure the ClientBuilder as needed for your client application
     
               
  
     
               
  //
Use HttpClient instead of the default HttpUrlConnection
     
               
  ClientConfig clientConfig= newClientConfig().connectorProvider(newApacheConnectorProvider());
     
               
  ClientBuilder clientBuilder= ClientBuilder.newBuilder();
     
               
  clientBuilder.withConfig(clientConfig);
     
               
  
     
               
  //
Setup SSL support to ignore self-assigned SSL certificates
     
              SSLContextBuilder
sslContextBuilder= newSSLContextBuilder();
     
              sslContextBuilder.loadTrustMaterial(TrustSelfSignedStrategy.INSTANCE);
     
              clientBuilder.sslContext(sslContextBuilder.build());
     
              clientBuilder.hostnameVerifier(NoopHostnameVerifier.INSTANCE);
     
               
               
  
     
              //
IBM jazz-apps use JEE Form based authentication
     
              clientBuilder.register(newJEEFormAuthenticator(webContextUrl,
userId,
password));

     
              //
STEP 2: Create a new OslcClient using the above configuration
     
               
  OslcClient client= newOslcClient(clientBuilder);

     
               
  //
STEP 3: Get the URL of the OSLC ChangeManagement service from the rootservicesdocument
     
               
  String catalogUrl= client.getCatalogUrl(webContextUrl,
OSLCConstants.OSLC_CM_V2);

     
               
  //
STEP 4: Find the OSLC Service Provider for the project area we want to
work with
     
               
  String serviceProviderUrl= client.lookupServiceProviderUrl(catalogUrl,
projectArea);

JEE FormAuthenticator
is included in oslc4j-client for convenience, and to provide an example
for how other authentication filters could be developed. 

Let me know if
this is sufficient to meet you OSLC4J Java client needs as we are in the
process of finishing up the 4.0.0 release.



Jim Amsden, Senior
Technical Staff Member
OSLC and Linked Lifecycle
Data
919-525-6575