Sequence (Mediation Sequence) is a sequence of Mediators. A message comes into the sequence, passes through the each mediator, in the order they are located in the sequence. So a Mediation Sequence is the generic building material of WSO2 ESB.
A Mediation Sequence can be theoretically used to process any type of message (binary, JSON, XML) passes through it given that mediators can successfully process these messages.
Therefore a mediation sequence can be used to,
- Proxy the messages to/from a web service
- Proxy the messages to/from a REST service
- And many more applications.....
A Proxy Service is the special module in WSO2 ESB that is designed to fulfill the requirements of the 1. (Proxy the messages to/from a web service) Therefore a Proxy service is a specialized Mediation Sequence with the support of Web Service Endpoints.
WSO2 ESB facilitates to create Proxy Services in different ways for the different types of requirements.
e.g.:
- WSDL based proxy - Used to create a proxy service using a given WSDL
- Pass through proxy - Used to simply create a proxy service using the Endpoint URL