Testing substitutability based on WSDL

Composition plays a cornerstone role for SOC in constructing applications, in which each component is a service with its exposing interface in WSDL. One overlooked potential downside to SOC is the high possibility of component service failure. Even a single component goes down, the whole application could wreak havoc. To prevent an application from such disaster, it would be best to exploit plenty services on the Internet to substitute the defective component. However, the simple idea results in a lot of challenges, such as how to rescue the application via service substitution, how to guarantee the compatibility after the replacement with rest components, and how to realize the substitution based on limited information of WSDLs. In this paper, we provide a solution to meet all above challenges. It consists of a formalism to test the substitutability, a mechanism to fulfil the judgement and a implemented tool.