Chapter 3 Service Endpoint Design

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Generally, you should consolidate related fine grained operations into more 

coarse grained ones to minimize expensive remote method calls.

More coarse grained service operations, such as returning catalog entries in

sets of categories, keep network overhead lower and improve performance. How 

ever, they are sometimes less flexible from a client's point of view. While finer 

grained service operations, such as browsing a catalog by products or items, offer

a client greater flexibility, these operations result in greater network overhead and

reduced performance.

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Keep in mind that too much consolidation leads to inefficiencies.

For example, consolidating logically different operations is inefficient and

should be avoided. It is much better to consolidate similar operations or opera 

tions that a client is likely to use together, such as querying operations.

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When exposing existing stateless session beans as Web service endpoints, en 

sure that the Web service operations are sufficiently coarse grained.

If you are planning to expose existing stateless session beans as Web service

endpoints, remember that such beans may not have been designed with Web ser 

vices in mind. Hence, they may be too fine grained to be good Web service end 

points. You should consider consolidating related operations into a single Web

service operation.

Good design for our airline reservation Web service, for example, is to expect

the service's clients to send all information required for a reservation destina 

tion, preferred departure and arrival times, preferred airline, and so forth in one

invocation to the service, that is, as one large message. This is far more preferable

than to have a client invoke a separate method for each piece of information com 

prising the reservation. To illustrate, it is preferable to have clients use the inter 

face shown in Code Example 3.1.

public interface AirlineTicketsIntf extends Remote {

public String submitReservationRequest(

AirReservationDetails details) throws RemoteException;

}

Code Example 3.1

Using Consolidation for Greater Efficiency (Recommended)