WWW/Internet - Portal do Software Público Brasileiro

IADIS International Conference WWW/Internet 2010A DESCRIPTION LANGUAGE FOR USER INTERFACESERVICESGerald Hübsch, Christian Liebing, Josef Spillner and Alexander SchillTechnische Universität Dresden, Institute for Systems Architecture, Chair of Computer NetworksABSTRACTIn this paper, we present the User Interface Service Description Language (UISDL) for the description of UI Services. UIServices allow UI component implementations to be globally distributed, flexibly integrated and dynamically bound intointeractive applications including, but not limited to, Rich Internet Applications. We present abstraction concepts,motivate design decisions, and discuss analogies between UISDL and WSDL as a classical service description language.KEYWORDSUI component, UISDL, user interface services, WSDL, XML Schema1. INTRODUCTIONWhile the service-based provisioning of business logic and data has reached a high degree of maturity andacceptance in the industry, the advantages of service-orientation for other building blocks of Rich Internetapplications (RIAs), especially their user interface (UI), have not yet been sufficiently addressed. Applicationdevelopers are today confronted with the need to choose one out of a large number of UI frameworkproviders, which in many cases may be already compromise. Due to a lack of standardization, they then facea 'vendor lock-in' which makes it difficult to flexibly integrate or exchange complex user interfacecomponents like maps, tables, calendars, or chart viewers, from third parties. Equally, providers of UIcomponents face difficulties in providing them 'as-a-service' i.e. in a standardized self-descriptive way thatenables their flexible integration, distribution and retrieval. We therefore believe that novel concepts arenecessary that make UI components available as UI Services. These concepts must address challenges thatrelate to the self-description of UI components that abstract from vendor- and implementation-specificdetails, mechanisms for their flexible integration into RIAs and their distribution on a global scale.The CRUISe project (Composition of Rich User Interface Services) addresses the challenges namedabove. The key idea is to enable UI components to be described and distributed as UI Services that can beflexibly composed into user interfaces for RIAs. The main benefit of UI Services is that UIs of RIAs candynamically bind the most suitable UI component implementation at runtime based on context, e.g. theplatform type or user preferences. In this paper, we present the User Interface Service Description Language(UISDL) as a central technological result of the project. UISDL is an XML format for describing UIcomponents as a set of abstract events, operations, and properties that define UI component interfaces in animplementation- and platform-independent way. UISDL supports the binding of these abstract interfacedefinitions to alternative component implementations provided by different vendors and for multipleplatforms, e.g. special versions for desktops and mobile phones. UISDL includes metadata for themanagement and distribution of UISDL descriptions through a UI Service repository. This paper is structuredas follows. Section 2 discusses related work. Section 3 presents UISDL together with the related concepts.Our runtime architecture for UI Services based on UISDL and sample applications built on top of UIServices are presented in section 4. We conclude our work and outline future work in section 5. To facilitateunderstanding, we will use an electronic map as an exemplary UI component throughout this paper.175