Chapter 3 Service Endpoint Design

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endpoint, on the other hand, you must do the synchronization yourself in the 

source code.

E

A JAX RPC service endpoint has to handle concurrent client access on its own, 

whereas the EJB container takes care of concurrent client access for an EJB 

service endpoint.

Transaction considerations

 The transactional context of the service imple 

mentation's container determines the transactional context in which a service 

implementation runs. Since a JAX RPC service endpoint runs in a Web con 

tainer, its transactional context is unspecified. There is also no declarative 

means to automatically start the transaction. Thus, you need to use JTA to ex 

plicitly demarcate the transaction.

On the other hand, an EJB service endpoint runs in the transaction context of 

an EJB container. You as the developer need to declaratively demarcate trans 

actions. The service's business logic thus runs under the transactional context 

as defined by the EJB's 

container transaction

 element in the deployment 

descriptor.

E

If the Web service's business logic requires using transactions (and the service 

has a JAX RPC service endpoint), you must implement the transaction 

handling logic using JTA or some other similar facility. If your service uses an 

EJB service endpoint, you can use the container's declarative transaction 

services. By doing so, the container is responsible for handling transactions 

according to the setting of the deployment descriptor element 

container 

transaction

. 

Considerations for method level access permissions

 A Web service's 

methods can be accessed by an assortment of different clients, and you may 

want to enforce different access constraints for each method. 

E

When you want to control service access at the individual method level, con 

sider using an EJB service endpoint rather than a JAX RPC service endpoint. 

Enterprise beans permit method level access permission declaration in the de 

ployment descriptor you can declare various access permissions for different 

enterprise bean methods and the container correctly handles access to these 

methods. This holds true for an EJB service endpoint, since it is a stateless ses