{title:'Matchers', updated:'9.0.0'}

{@link oajr.matcher.RestMatcher RestMatchers} are used to allow multiple Java methods to be tied to the same HTTP method and path but differentiated by some request attribute such as a specific header value.

##### Example:

| // GET method that gets invoked for administrators | @RestGet(path="/*", matchers=IsAdminMatcher.class) | public Object doGetForAdmin() { | ... | } | | // GET method that gets invoked for everyone else | @RestGet("/*") | public Object doGetForEveryoneElse() { | ... | }

The interface for matchers is simple:

| public class IsAdminMatcher extends RestMatcher { | | @Override /* RestMatcher */ | public boolean matches(RestRequest req) { | return req.isUserInRole("ADMINS_GROUP"); | } | }

- If no methods are found with a matching matcher, a 412 Precondition Failed status is returned.
- If multiple matchers are specified on the same method, ONLY ONE matcher needs to match for the method to be invoked.
- Note that you CANNOT define identical paths on different methods UNLESS you use matchers.
  That includes paths that are only different in variable names (e.g. "/foo/{bar}" and "/foo/{baz}").
  If you try to do so, a ServletException will be thrown on startup.
- Methods with matchers take precedence over methods without.
  Otherwise, methods are attempted in the order they appear in the class.

- {@link oajr.annotation.RestOp#matchers RestOp(matchers)}
- {@link oajr.matcher.MultipartFormDataMatcher}
- {@link oajr.matcher.UrlEncodedFormMatcher}