JAX-WS client programming model
The Java™ API for XML-Based Web Services (JAX-WS) web service client programming model supports both the Dispatch client API and the Dynamic Proxy client API. The Dispatch client API is a dynamic client programming model, whereas the static client programming model for JAX-WS is the Dynamic Proxy client. The Dispatch and Dynamic Proxy clients enable both synchronous and asynchronous invocation of JAX-WS web services.
- Dispatch client: Use this client when you want to work at the XML message level or when you want to work without any generated artifacts at the JAX-WS level.
- Dynamic Proxy client: Use this client when you want to invoke a web service based on a service endpoint interface.
Dispatch client
XML-based web services use XML messages for communications between web services and web services
clients. The JAX-WS APIs provide high-level methods to simplify and hide the details of converting
between Java method invocations and their associated XML messages. However, in some cases, you might
desire to work at the XML message level. Support for invoking services at the XML message level is
provided by the Dispatch client API. The Dispatch client API,
javax.xml.ws.Dispatch
, is a dynamic JAX-WS client programming interface. To write a
Dispatch client, you must have expertise with the Dispatch client APIs, the supported object types,
and knowledge of the message representations for the associated Web Services Description Language
(WSDL) file. The Dispatch client can send data in either MESSAGE
or
PAYLOAD
mode. When using the javax.xml.ws.Service.Mode.MESSAGE
mode, the Dispatch client is responsible for providing the entire SOAP envelope including the
<soap:Envelope>
, <soap:Header>
, and
<soap:Body>
elements. When using the
javax.xml.ws.Service.Mode.PAYLOAD
mode, the Dispatch client is only responsible for
providing the contents of the <soap:Body>
and JAX-WS includes the payload in
a <soap:Envelope>
element.
javax.xml.transform.Source
: UseSource
objects to enable clients to use XML APIs directly. You can useSource
objects with SOAP or HTTP bindings.- JAXB objects: Use JAXB objects so that clients can use JAXB objects that are generated from an XML schema to create and manipulate XML with JAX-WS applications. JAXB objects can only be used with SOAP or HTTP bindings.
javax.xml.soap.SOAPMessage
: UseSOAPMessage
objects so that clients can work with SOAP messages. You can only useSOAPMessage
objects with SOAP bindings.javax.activation.DataSource
: UseDataSource
objects so that clients can work with Multipurpose Internet Mail Extension (MIME) messages. UseDataSource
only with HTTP bindings.
javax.xml.transform.Source
, the
call to the Dispatch client API is similar to the following code
example:Dispatch<Source> dispatch = … create a Dispatch<Source>
Source request = … create a Source object
Source response = dispatch.invoke(request);
The
Dispatch parameter value determines the return type of the invoke()
method.- Synchronous invocation for requests and responses using the
invoke
method - Asynchronous invocation for requests and responses using the
invokeAsync
method with a callback or polling object - One-way invocation using the
invokeOneWay
methods
Refer to Chapter 4, section 3 of the JAX-WS specification for more information on using a Dispatch client.
Dynamic Proxy client
The static client programming model for JAX-WS is the called the Dynamic Proxy client. The Dynamic Proxy client invokes a web service based on a Service Endpoint Interface (SEI) which must be provided. The Dynamic Proxy client is similar to the stub client in the Java API for XML-based RPC (JAX-RPC) programming model. Although the JAX-WS Dynamic Proxy client and the JAX-RPC stub client are both based on the Service Endpoint Interface (SEI) that is generated from a WSDL file , there is a major difference. The Dynamic Proxy client is dynamically generated at run time using the Java 5 Dynamic Proxy functionality, while the JAX-RPC-based stub client is a non-portable Java file that is generated by tooling. Unlike the JAX-RPC stub clients, the Dynamic Proxy client does not require you to regenerate a stub prior to running the client on an application server for a different vendor because the generated interface does not require the specific vendor information.
The Dynamic Proxy instances extend the java.lang.reflect.Proxy
class and
leverage the Dynamic Proxy function in the base Java SE Runtime Environment (JRE)
6. The client application can then provide an interface that is used to create the proxy instance
while the runtime is responsible for dynamically creating a Java object that represents the SEI.
- Synchronous invocation for requests and responses using the
invoke
method - Asynchronous invocation for requests and responses using the
invokeAsync
method with a callback or polling object - One-way invocation using the
invokeOneWay
methods
Refer to Chapter 4 of the JAX-WS specification for more information on using Dynamic Proxy clients.