Organisations are increasingly using the Web not only to sell products and deliver information, but also for providing their services to businesses and individual customers. Typically, applications within an organisation that provide these services are required to integrate existing enterprise information systems to offer new business functions. Organisations need to ensure that these services are available, scalable and also adaptive to guarantee that user interactions are promptly processed even under highly dynamic scenarios. In most cases, organisations use application servers with multi-tier architecture for the delivery of their services. In the following, we will refer to services provided by a single organisation as Basic Services (BSs). Presence of a wide variety of BSs over the Internet has created an exciting new business opportunity of providing value added, inter-organisational services by composing multiple BSs into new Composite Services (CSs).
An example might be a �holiday planner CS� that makes use of travel booking, hotel reservation and holiday insurance services. Indeed, emerging Web services standards such as SOAP (for service invocation), UDDI (for web service discovery) and WSDL (for web service description) are a step in this direction. Just like a BS, a CS needs to be available, scalable and adaptive. Middleware technologies for implementing BSs over application servers are relatively well advanced and include Java 2 Enterprise Edition (J2EE), Microsoft .NET or the OMG CORBA. Present day application servers are capable of making stateless BSs available (through replication) and adaptive (through load balancing), but lack support for enriching stateful BSs with the same properties. On the other hand, middleware technology for inter-organisational computing has not yet advanced to a stage where requirements of making CSs available, scalable and adaptive can be met by standard solutions obtained by applying existing research results on reliable distributed computing. There is an urgent need for research in this area, taking into account a number of factors.
The goal of the ADAPT project is to advance middleware technologies to support adaptive and composable web services. All the software resulting from the project will be open-source.