Web Service Asynchronous Operation Of The Wireless Environment

Asynchronous operation is an important functionality in the context of distributed object frameworks because in many situations Web services caller should not block during remote invocations, such as wireless environment. The complexity and composition of Web services make Web services working in an asynchronous operation style and substituting RPC operation style gradually as a leading operation style.In this paper, the asynchronous operation models, asynchronous Web services implementation methods, the characters of wireless devices and the JSR172 specification are analyzed based on the requirements of a remote conference system combing with the development trends of the Web services. An asynchronous operations model of Web services for J2ME--AWSM4ME (Asynchronous Web Services Model for J2ME), which enables wireless devices call Web services asynchronously, is put forward. This model binds SOAP requests with SMTP, FTP, etc. protocols to realize a mechanism of store and forward with the help of a proxy called J2ME Asynchronous Web Services Proxy (JAWSP) and the persistence ability of Email systems and FTP systems. All requests and responses are transferred between wireless devices and Web services providers via JAWSP, which enables the separation of request operations and responses operations and provides the primary reliability and security.The designs of J2ME Asynchronous Web Services Proxy, J2ME Web services clients (callers), interaction protocols between callers and providers are discussed, as well as the enhancement of system reliability and security, etc. An Email-based solution of AWSM4ME and a FTP-based solution are also introduced aimed at the problems exited in enterprise applications of wireless devices. And at last, an implementation of AWSM4ME based on email systems is brought forward.