Deprecated feature[Java programming language only]

REST data services overview

The WebSphere® eXtreme Scale REST data service is a Java™ HTTP service that is compatible with Microsoft WCF Data Services (formally ADO.NET Data Services) and implements the Open Data Protocol (OData). Microsoft WCF Data Services is compatible with this specification when using Visual Studio 2008 SP1 and the .NET Framework 3.5 SP1.

Compatibility requirements

The REST data service allows any HTTP client to access a data grid. The REST data service is compatible with the WCF Data Services support supplied with the Microsoft .NET Framework 3.5 SP1. RESTful applications can be developed with the rich tooling provided by Microsoft Visual Studio 2008 SP1. The figure provides an overview of how WCF Data Services interacts with clients and databases.

Figure 1. Microsoft WCF Data Services
With Microsoft WCF Data Services, the HTTP client communicates with the REST service, which communicates directly with the database.

WebSphere eXtreme Scale includes a function-rich API set for Java clients. As shown in the following figure, the REST data service is a gateway between HTTP clients and the WebSphere eXtreme Scale data grid, communicating with the grid through an WebSphere eXtreme Scale client. The REST data service is a Java servlet, which allows flexible deployments for common Java Platform, Enterprise Edition (JEE) platforms, such as WebSphere Application Server. The REST data service communicates with the WebSphere eXtreme Scale data grid using the WebSphere eXtreme Scale Java APIs. It allows WCF Data Services clients or any other client that can communicate with HTTP and XML.

Figure 2. WebSphere eXtreme Scale REST data service
HTTP Clients communicate with WebSphere eXtreme Scale REST service with OData. The Rest Service communicates with the data grids. The data grids are backed by a database.

Refer to the Configuring REST data services, or use the following links to learn more about WCF Data Services.

Features

This version of the eXtreme Scale REST data service supports the following features:
  • Automatic modeling of eXtreme Scale EntityManager API entities as WCF Data Services entities, which includes the following support:
    • Java data type to Entity Data Model type conversion
    • Entity association support
    • Schema root and key association support, which is required for partitioned data grids
    See Entity model for more information.
  • Atom Publish Protocol (AtomPub or APP) XML and JavaScript Object Notation (JSON) data payload format.
  • Create, Read, Update and Delete (CRUD) operations using the respective HTTP request methods: POST, GET, PUT and DELETE. In addition, the Microsoft extension: MERGE is supported.
    [Version 8.6 and later]
    [Version 8.6 and later]Deprecated featureNote: The upsert and upsertAll methods replace the ObjectMap put and putAll methods. Use the upsert method to tell the BackingMap and loader that an entry in the data grid needs to place the key and value into the grid. The BackingMap and loader does either an insert or an update to place the value into the grid and loader. If you run the upsert API within your applications, then the loader gets an UPSERT LogElement type, which allows loaders to do database merge or upsert calls instead of using insert or update.
  • Simple queries, using filters
  • Batch retrieval and change set requests
  • Partitioned data grid support for high availability
  • Interoperability with eXtreme Scale EntityManager API clients
  • Support for standard Java EE Web servers
  • Optimistic concurrency
  • User authorization and authentication between the REST data service and the eXtreme Scale data grid

Known problems and limitations

  • Tunneled requests are not supported.