Chapter 8 Flashcards
Service-Oriented Architecture (SOA) has
3 main services. Name them:
Service requestor; Service Provider; Service discovery
How service requestor works?
Service requestor finds required service via service discovery and bids to services via service provider.
Services provider provides e-business services and publishes availability of these services.
Service Discovery allows service registry
How service discovery works?
DIrectory/repository for WS descriptions; APIs and protocols for directory interaction
How service description works?
It has a common base language (XML), interfaces (WSDL, which extend traditional IDLs), business protocols (WSCL, BPEL) and properties and semantics (UDDI, WS-Policy)
SOAP - Simple Object Access Protocol. What is it?
It defines how to format information in XML so that it can be exchanged between peers
- processing rules for SOAP messages
- how to transport SOAP messages on top of HTTP, SMTP
What is contained in THE SOAP Envelope Framework?
SOAP Envelope Framework
SOAP Envelope is the root element of the SOAP message and contains optional fault element, optional header element and a mandatory body. The body element contains arbitrary xml (application specific) child element are called body entries.
A SOAP envelope can have any number of headers. The header can be used to reservation identification, customer identification and information, authentication, authorization, transaction management, payment processing, tracing, auditing, etc…
SOAP is stateless, one-way message exchange paradigm.
define Web Service Description Language (WSDL)
- it works as a Documentation for distributed systems. It’s a recipe for automating the details involved in applications communication
It Describes the mechamis to access the web service (which protocol is used, the service location)
What are the ingredients of WSDL?
ABSTRACT part: where is defined the types, the message exchange pattern, the operations and the interface
CONCRETE part: Where defines the binding (e.g. SOAP/HTTP, HTTP GET/POST), endpoint (single endpoint identified by a network address supporting a particular binding, service (group endpoints related to the same service interface but expressed by different protocols)
what is Message Exchange Patterns (MEP)?
Defines interactions paradigms. Defined by WSDL specification
Web Service Policies
Web service capabilities and requirements need to be described as metadata. Examples: addressing, security, transaction, reliability
what is the goal of Universal Description Discovery and Integration (UDDI)?
t enables service discovery. It catalogues services based on published information of service providers. Specify technical binding information to actually communicate with the selected service. It registry serves as a directory of web services, allowing to search „by what“ and „by how“instead of just „by name“
JAX-WS
Java API for XML Web Services
