src-openfeign/jaxrs

Feign JAXRS

This module overrides annotation processing to instead use standard ones supplied by the JAX-RS specification. This is currently targeted at the 1.1 spec.

Limitations

While it may appear possible to reuse the same interface across client and server, bear in mind that JAX-RS resource annotations were not designed to be processed by clients. Moreover, JAX-RS 2.0 has a different package hierarchy for client invocation. Finally, JAX-RS is a large spec and attempts to implement it completely would be a project larger than feign itself. In other words, this implementation is best efforts and concedes far from 100% compatibility with server interface behavior.

Currently Supported Annotation Processing

Feign only supports processing java interfaces (not abstract or concrete classes).

ISE is raised when any annotation's value is empty or null. Ex. Path("") raises an ISE.

Here are a list of behaviors currently supported.

Type Annotations

@Path

Appends the value to Target.url(). Can have tokens corresponding to @PathParam annotations.

Method Annotations

@HttpMethod meta-annotation (present on @GET, @POST, etc.)

Sets the request method.

@Path

Appends the value to Target.url(). Can have tokens corresponding to @PathParam annotations.

@Produces

Adds the first value as the Accept header.

@Consumes

Adds the first value as the Content-Type header.

Parameter Annotations

@PathParam

Links the value of the corresponding parameter to a template variable declared in the path.

@QueryParam

Links the value of the corresponding parameter to a query parameter. When invoked, null will skip the query param.

@HeaderParam

Links the value of the corresponding parameter to a header.

@FormParam

Links the value of the corresponding parameter to a key passed to Encoder.Text<Map<String, Object>>.encode().