Michael Gilfix Online

Using proper Web Service interface design can greatly improve application responsiveness and simplify integration logic. Poor design will not only bog down logic, but actually increase the complexity of both client and server-side implementation by requiring both to handle a larger number of possible error cases. This post attempts to capture three key patterns for designing/improving Web Service interfaces. While this article approaches the problem from the perspective of Web Services, many of these principles apply to Web Service design.

Appropriate Granularity:

The traditional interface design paradigms that folks are used to using in OOP and functional languages are often inappropriate for remote interfaces. They favor having many different methods that can be used to query information or state about an objects internals. This is particularly true for data objects. Since each query results in a remote interface invocation, querying information can quickly add up. A better approach is to use the Data Transfer Object (DTO) pattern that is heavily talked about in the concept of remote EJBs. The DTO is a data object that contains all queriable information in a single data object, which is transferred once. The cost of transferring more data in a single shot is marginal compared to the latency cost of going back and forth. This is particularly true for interfaces that allow you to create/update/query/delete data objects.