@GET
  @Path("{userName}")
  @Produces("text/plain")
  @ApiOperation(value = "Get group member", nickname = "MemberService#getMember", notes = "Returns member details.", response = MemberResponse.class)
  @ApiImplicitParams({
    @ApiImplicitParam(name = "fields", value = "Filter member details", defaultValue = "MemberInfo", dataType = "string", paramType = "query")
  })
  @ApiResponses(value = {
    @ApiResponse(code = 200, message = "Successful operation", response = MemberResponse.class)}
  )
  public Response getMember(@Context HttpHeaders headers, @Context UriInfo ui, @ApiParam(value = "group name", required = true)  @PathParam("groupName") String groupName,
                            @ApiParam(value = "user name", required = true) @PathParam("userName") String userName) {
    return handleRequest(headers, null, ui, Request.Type.GET, createMemberResource(groupName, userName));
  }
Gets member.
Handles: GET /groups/{groupname}/members/{username} requests.

@param headers    http headers
@param ui         uri info
@param groupName    group name
@param userName   the user name
@return information regarding the specific member
ambari-server/src/main/java/org/apache/ambari/server/api/services/groups/MemberService.java