You can build a request filter for the server by implementing the javax.ws.rs.container.ContainerRequestFilter interface. This filter intercepts the REST API calls and runs before the request invokes the REST resource. You will find this useful for performing authorization checks, auditing requests, or manipulating the request header parameters before invoking the REST API implementation.

The ContainerRequestFilters implementation falls into two categories on the basis of the stage in the request processing cycle that the filters are executed at:

• Postmatching: These filters are executed after identifying the matching Java class resource method for processing the incoming HTTP request (the REST API call). The ContainerRequestFilters implementations, by default, are postmatching (unless you designate them as @PreMatching).
• Prematching: These filters are executed before identifying the matching resource class for a REST API call. Prematching ContainerRequestFilters are designated with the @javax.ws.rs.container.PreMatching annotation.