tailieunhanh - Java Testing and Design- P6

Java Testing and Design- P6: The ultimate test of every software construction effort is the user’s success using the product to accomplish some practical goal. No matter how much state-of-the-art technology goes into the software, success can only be judged through the lens of the user. | Web Service Scalability Techniques 229 parameters and data types used to make a SOAP request and receive a response. WSDL is machine parsable and enables development tools and application servers to generate program source code. SOAP provides better extensibility and reduces brittleness over XML-RPC by introducing the many extra layers of the SOAP stack described in Figure 7-2. However with greater flexibility comes a greater possibility of incompatibility and scalability problems. Web Service Scalability Techniques SOAP and WSDL-based Web services use a multistep process to complete a transaction. Many techniques and system architectures attempt to improve Web service scalability and performance. Understanding these techniques is important to validate the results in a test. The Web service request often begins with business logic of your application learning the method and parameter to call from a WSDL document. As an example here is part of the WSDL for a publicly available Web service that returns the current weather for a . postal zip code. message name part name message message name part name message getTempRequest zipcode type xsd string getTempResponse return type xsd float The weather service requires you to call the getTempRequest method by passing in a zipcode value as a string and receiving the temperature as a floating-point value in the response. Since the WSDL rarely changes many developers embed the WSDL definition into their code to avoid the overhead of getting the WSDL every time. While this will improve performance it also works against solving brittleness and becomes a maintenance headache when the WSDL eventually changes. The better way to avoid maintenance problems is to cache the WSDL in the centralized database and then periodically check the timestamp version number of the WSDL to see if a newer one is available. Another way for software developers to try to improve performance is to turn XML validation off. For systems that do no use .