Consuming a Web Service 
To create and configure a service consumer, you must first generate a consumer proxy. The consumer proxy encapsulates communication and takes over the control of technical processes. The consumer proxy is used to create a connection to the server of the Web service required. While the developer programs the business application, the technical part – for example, the automatic packing of calls into a SOAP message or the evaluation of incoming messages – is taken care of using the proxy.
It is not of importance to a service consumer which technology is used on the side of the service provider. It is possible to use Web services from a non-SAP system, irrespective of the implementation behind it.
After proxy generation, you can call the service from a program.
Features
Consuming a service comprises the following steps:
Configuring a Service Consumer
During proxy generation, all the objects required to call a Web service are created. This includes the logical ports. This is an SAP-specific concept for the configuration of runtime features for consumer proxies. Runtime features are features that must be configured in the runtime environment when the service consumer is activated. So, for example, the logical port contains the URL address to be used for calling the service.
For more information, refer to the section Configuring a Consumer Proxy (SOA Manager). Read also the section entitled Working with Service Groups.
Calling a Service from an Application
During proxy generation, a proxy class as well as data types for parameter transmission are generated.
Create a program and drag the consumer proxy using drag and drop to the required position in the program. The service can be used directly after the proxy has been generated, the logical port has been configured, and the services from a program have been called.
Using the outside-in approach, you develop the Web service in the ES Repository. Choosing an interface pattern when modeling a service interface determines which programming model and which Web service processing type is to be used.
The Interface patterns section covers the following areas:
Consuming A Stateless Web Service
Consuming A Stateless Web Service (XI 3.0 compatible)
Consuming A Stateful Web Service
Consuming a TU&C/C Web Service
While the Stateless and TU&C/C interface patterns can be used with both synchronous and asynchronous communication, Stateful and Stateless (XI 3.0 compatible) interface patterns only support synchronous communication.