C. Web Services
Development
Figure 5 shows the workflow for Web Services development.
There are eight steps, namely:
- Gather user requirements.
- Analyze business components to be reused or create new
service.
- Design the Web Service (WS).
- Develop WS by implementing business logic with the used of
interface and implementation classes. The interface class is where the
service interface will be exposed for consumption and the implementation
class is actual implementation of the services derived from software
components
- Build WS by wrapping component into WS.
- Deploy WS to the target web server based on the deployment
script (which is server specific).
- Test and debug WS using web service client (where the
client is server specific).
- Publish WS if publishing to service registry is required.
As shown in Figure 5, Step 5: Build,
Step 6: Deploy and Step 8: Publish are specific to Web Services development as compared
to component-based development. Step 7: WS Test requires a platform specific WS
client to test the WS. The artifacts generated from these steps are also
specific to Web Services. The outputs (i.e. interface and implementation
classes) produced from Step 4 are specific to Web Services as well.
Fig.5: Web
Services Development Workflows
By comparing agile software development steps and Web Services
development steps, we are able to extend Web Services specific steps into the
agile development methodology
D. Web Services
Characteristics and Best Practices
The realization of SOA is
centered on Web Services (WS). It is important to understand fully the
characteristics of Web Services, in terms of the dos and donts for WS, form
the basis of the best practices for Web Services development. These
characteristics affect the design and implementation of Web Services. The
following sub-sections discuss the characteristics of Web Services and its
associated best practices.
WSBP1. Web Services
Styles. There are two most common styles of Web Services, namely remote procedure
call (RPC) style WS and document style WS. The differences between these two
styles are summarized in Table 1. The RPC-styled offers simplicity and better
tooling support. The document-styled offers greater flexibility and decoupling
of services.
Table 1: Web
Services Styles
