Building block 1 – service

Services are the greenish rectangular boxes drawn in Fig. 1. The meaning of service in PLASH platform is similar to the concept of service proposed in SOC paradigm. As with most other SOA implementations, a service registered on the PLASH platform can be existed in various forms. It can be a Java object built on the PLASH platform and hosted inside our PLASH server. It can also be a service provided by an external machine that connects to the PLASH server via network. An example of heterogeneous services coexisting in the same system is illustrated in the next section.

A service that is built on the PLASH platform is named internal service as it is usually hosted internally and has more efficient access to internal resources as well as other internal services. We referred to SOCM and implemented internal services as service components. Specifically, a simple internal service is composed by a single component. The component is implemented by using SpringBean and Spring container. Component chaining is available to support service mashup. On the other hand, a single component may provide multiple services. This feature allows better flexibility for service designers. It is one aspect that the PLASH design deviates from SOCM.