Enforce trailing slash with redirect

Graph `PUT` method returns `308 Permanent Redirect` with `Locatioon` instead of `422 Unprocessable Entity`

Author: namedgraph

src/main/java/com/atomgraph/linkeddatahub/resource/Graph.java

@@ -62,6 +62,7 @@
 import jakarta.ws.rs.core.Request;
 import jakarta.ws.rs.core.Response;
 import jakarta.ws.rs.core.Response.ResponseBuilder;
+import static jakarta.ws.rs.core.Response.Status.PERMANENT_REDIRECT;
 import jakarta.ws.rs.core.SecurityContext;
 import jakarta.ws.rs.core.UriInfo;
 import jakarta.ws.rs.ext.MessageBodyReader;
@@ -212,11 +213,16 @@ public Response put(Model model, @QueryParam("default") @DefaultValue("false") B
             throw new WebApplicationException("Method '" + HttpMethod.PUT + "' is not allowed on document URI <" + getURI() + ">", Response.status(Response.Status.METHOD_NOT_ALLOWED).allow(getAllowedMethods()).build());
         }
 
-        // enforce that request URI always end with a slash and is present in the RDF document
+        // enforce that request URI always end with a slash - by redirecting to it if doesn't not already
         if (!getURI().toString().endsWith("/"))
         {
-            if (log.isErrorEnabled()) log.error("Document URI <{}> does not end with a slash", getURI());
-            throw new WebApplicationException("Document URI <" + getURI() + "> does not end with a slash", UNPROCESSABLE_ENTITY.getStatusCode()); // 422 Unprocessable Entity
+            String uriWithSlash = getURI().toString() + "/";
+
+            if (log.isDebugEnabled()) log.debug("Redirecting document URI <> to <{}> in order to enforce trailing a slash", getURI(), uriWithSlash);
+
+            return Response.status(PERMANENT_REDIRECT).
+                location(URI.create(uriWithSlash)).
+                build();
         }
 
         new Skolemizer(getURI().toString()).apply(model);

src/main/java/com/atomgraph/linkeddatahub/server/exception/ResourceExistsException.java

@@ -26,6 +26,7 @@
  * 
  * @author Martynas Jusevičius {@literal <martynas@atomgraph.com>}
  */
+@Deprecated
 public class ResourceExistsException extends ModelException
 {
 

src/main/java/com/atomgraph/linkeddatahub/server/mapper/ResourceExistsExceptionMapper.java

@@ -32,6 +32,7 @@
  * 
  * @author Martynas Jusevičius {@literal <martynas@atomgraph.com>}
  */
+@Deprecated
 public class ResourceExistsExceptionMapper extends ExceptionMapperBase implements ExceptionMapper<ResourceExistsException>
 {