Problems with MSF4J and #MatrixParam - wso2

Question

Folks, I have found what seems to be a problem with / (bug in ?) MSF4J as including an #MatrixParam annotated variable in a URI causes the affected (micro)service to either 'hang' indefinitely, or if accessed via a browser, to give a "404 Not Found" message for the path/endpoint, even when correct.
Here is a code fragment that illustrates the problem - it compiles ok (eclipse/maven) and deploys without errors using microservicesrunner() in the usual way.
package org.test.service;
import javax.ws.rs.GET;
import javax.ws.rs.MatrixParam;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Response;
#Path("books")
public class MPTest { // MatrixParam Test
#GET
#Produces(MediaType.TEXT_PLAIN)
#Path("/query")
// method to respond to 'GET' requests
public Response getListOfBooks(#MatrixParam("Author") String author) {
// do something in here to get book data from DB and sort by titles
List<String> titles = .......;
return Response.status(200) .entity("List of Books by " +author+ "ordered by title " + titles).build();
}
}
With this code fragment, accessing the URL "(host:8080)/books/query;Author=MickeyMouse" should cause a list of books by that author to be retrieved from the DB (I have omitted the actual code that does so for clarity, as it is not relevant to this post).
However, it does not get there, so that code isnt executed. As far as I can tell with a debugger, no #MatricParam value is retrieved - it remains null until the process times out. Things like curl and wget just hang until they time out, and from a browser, the best I can get is a 404 not found error for the URI, even though it is valid.
However, if I replace the #MatrixParam with a #PathParam it works perfectly, and can I get the URL string retrieved in its entirity. The URI that I get is as expected - no odd hex characters, no typos, and so forth. The URI entered is what you get back. So, no problem there.
Behaviour is also consistent across platforms (couple of flavours of Linux, and three versions of Windoze), so it is not anything to do with the OS itself. Similarly, I get the same behavior with multiple clients and tools, so it isnt a problem there either.
So, it appears to be a problem within the MSF4J framework / domain, and I could use some support / help / suggestions here as I've reached the point of tearing my hair out..... Any ideas, folks?
The only reference I can find to a similar problem was closed as 'off topic' without a reply (see Rest API Matrix param annotation) so I think that this needs re-opening as it seems to be a genuine problem....
Regards, and thanks in advance for any help,
Rick

Answer 1

#MatrixParam is not supported with MSF4J at the moment. You can create a GitHub issue. So we can implement that support in future releases.