ContextService
From MobiComp
Summary
The ContextService is the core element of the MobiComp infrastructure. This represents a simple interface to a tuplespace, extended with event notification. It acts as a store for ContextElements encapsulating each part of the context of a ContextEntity, and enables coordination between the components of context-aware applications. The approach here is similar to that employed in several other ubiquitous computing support infrastructures.
The storage components behind the ContextService interface may be configured to support different scales of context-aware applications: for simple, stand-alone, applications, for multiple applications on a single device, or for distributed storage. In the latter case, servers at well-known addresses can be employed as proxies for mobile devices where their network connections (e.g. via GSM/GPRS) prevent direct requests from the Internet to the device.
The ContextService interface provides put, get and remove methods to support the tuplespace model. Registration and notification methods support an event-based model and so avoid the need for continuous polling for interesting events. In addition, a general query interface is being developed to enable clients to enquire about the content of the store, retrieve element schemas, and to extent the simple ‘get’ interface with general-purpose XQuery requests.
See also:
Developer info
See the source code:
