WSProxy - Web Service Proxy Interface

Diagram

Working

This interface helps to introduce state and steering in a custom service. Thus the complete life-cycle from invocation to starting, suspend/resume and termination can be controlled using Webservice calls. An error-handler is provided to convey errors to the WSProxyClient (the client side that invokes and steers the computation), which can in turn take custom actions such as

Ignore the error
Terminate the service
Invoke some code, a javascript function in our case

The structure is as follows

The basic element is a WSSConnector object that exposes itself as a Web Service using Apache Axis

With every new Session, an InvocationContainer is created that invokes the appropriate ProxyWebService. We provide 2 implementations for the ProxyWebService, namely
- RunnableProxyWebService - Provides a thread safe implementation with additional features such as START, SUSPEND, RESUME and STOP. The service is provided the required i/o streams.
- WrapperProxyWebService - Provides a wrapper around a custom object to serve as a webservice. The object reads/writes data from topics, files on its own.

Examples / Demos

Crisis Grid Demo

Uses the WrapperProxyWebService to provide life-cycle operations to custom code that reads/ writes from/to pre-defined streams.

Demo Page

Network Sensor Demo

Uses the RunnableProxyWebService to provide two services whose function is to work on chunks of data.

Demo Page