REST = Representational State Transfer

https://shengwangi.blogspot.com/2016/02/response-for-get-post-put-delete-in-rest.html?_sm_au_=iHVZSvGVVk7KGtQqsJk3kKtQTCQFp
Table https://lh3.googleusercontent.com/-cpYCrP36Nc8/VsWO7emBMRI/AAAAAAAAAyU/0rv7Lnl0aNI/s1600-h/image%25255B5%25255D.png
  saved as ~/sharedhome/mydocs/restOperations.png


I haven't seen explained how it handles operations upon elements, since it is
all assignment-based.

Operations:  GET PUT POST DELETE
are applied to collections and elements in different but similar ways.
Nice table at https://en.wikipedia.org/wiki/Representational_state_transfer#Relationship_between_URL_and_HTTP_Methods
and http://www.restapitutorial.com/lessons/httpmethods.html
    POST=insert.  Other than generally only doing collection.POST to insert
     a new element, the other operations apply to either collection or element.
Non-intuitives:
    Collection.PUT *REPLACES* the entire collection.
    *.POST creates a new Element and returns the new Element ID/URL.
    I.e., POST is what one would expect to be performed by a .put() operation.
      POST does NOT UPDATE any existing item.
PUT and DELETE must be idempotent.

PATCH vs. PUT
PUT replaces everything in an existing record.
PATCH does pointed updates to an existing record.
Modify operation generally done by HTTP PATCH.
https://restfulapi.net/http-methods/#patchhttps://restfulapi.net/http-methods/#patch

JAX-RS.  All of this straight from http://en.wikipedia.org/wiki/Jax-rs
API for server-side annotations.
Implementations
    Apache CXF
    Sun Jersey
    JBoss RESTEasy
    Restlet
    Apache Wink's server module
ANNOTATIONS
    @Path  relative path for resource class
    @GET, @PUT, @POST, @DELETE   obviously...
    @Produces, @Consumes  specifies returned/acceptable MIME media types
    @PathParam, @QueryParam, @HeaderParam, @CookieParam, @MatrixParam,
            @FormParam  (Only works with POSTs and requires form mime-type)
    [+ RESTEasy-specific Form which assembles the bean from http params]

RESTEasy
    @Provider?
    Servlet org.jboss...HttpServletDispatcher.  (By default initializes too).
    OR org.jboss...FilterDispatcher (which allows for skipping non-JAX-RS URLs).
    Requires servlet init param javax.ws.rs.Application.  I guess the
     root-level resource bean.  About 10 other optionals.
    The servlet init param resteasy.sevlet.mapping.prefix must be set if you
     use a url-pattern other than /*.
    If the dispatcher servlet's initialization is too late (like if using
     Spring), then also add listener class ...ResteasyBootStrap.
     [I don't know if this is needed when using the FilterDispatcher].
SPRING
    RESTEasy provides its own SpringContextLoaderListener that checks all
     beans for REST annotations as they load.
    Constructor injection not supported.

URLs
Atomic: /resource/{id} ->200,404
LIST:   /resource[?...] ->200,404