Spring Data Query Method with Optional @Param

Question

Is it possible to allow query method @Params to be optional, specifically in the case of Spring Data REST?

For example, I'd like to bind a very similar search to the same resource path. To do this now, I would need something like the following:

@RestResource(path = "driver", rel = "byDriver")
List<Bar> findByDriverId(@Param("id") String id, Pageable pageable);

@RestResource(path = "driverAndSpan", rel = "byDriverAndSpan")
List<Bar> findByDriverIdAndStartTimeGreaterThanEqualAndEndTimeLessThanEqual(@Param("id") String id, @Param("start") Date start,
        @Param("end") Date end, Pageable pageable);

Which gives me:

byDriver: {
  href: "http://localhost:8080/foo/search/driver{?id,page,size,sort}",
},
byDriverAndSpan: {
  href: "http://localhost:8080/foo/search/driverAndSpan{?id,start,end,page,size,sort}",
}

What I want is to be able to see something like the following path, where start and end are optional parameters, rather than defining multiple methods in my Repository.

byDriverAndSpan: {
  href: "http://localhost:8080/foo/search/driverAndSpan{?id,*start,*end,page,size,sort}",
}

Which could potentially look like:

@RestResource(path = "driverAndSpan", rel = "byDriverAndSpan")
List<Bar> findByDriverIdAndStartTimeGreaterThanEqualAndEndTimeLessThanEqual(@Param("id") String id, @Param(value = "start", optional = true) Date start,
        @Param(value = "end", optional = true) Date end, Pageable pageable);

Answer 1

Maybe you can define a 'main' function as default which will delegate to the other functions. Something like this

@RestResource(path = "driverAndSpan", rel = "byDriverAndSpan")
default List<Bar> findByDriverIdAndOptionalStartTimeGreaterThanEqualAndOptionalEndTimeLessThanEqual(@Param("id") String id, @Param(value = "start", optional = true) Date start,
        @Param(value = "end", optional = true) Date end, Pageable pageable) {
   if(start != null && end != null) {
      return findByDriverIdAndStartTimeGreaterThanEqualAndEndTimeLessThanEqual(id, start, end, pageable);
   }
   return findByDriverId(id, pageable);
}

I think you can even use Optional as a parameter type, then you can use function overloading

@RestResource(path = "driverAndSpan", rel = "byDriverAndSpan")
default List<Bar> findByDriverIdAndStartTimeGreaterThanEqualAndEndTimeLessThanEqual(
@Param("id") String id, @Param(value = "start") Optional<Date> start,
        @Param(value = "end") Optional<Date> end, Pageable pageable) {
   if (!start.isEmpty() && !end.isEmpty()) {
      return findByDriverIdAndStartTimeGreaterThanEqualAndEndTimeLessThanEqual(id, start.get(), end.get(), pageable);
   }
   return findByDriverId(id, pageable);
}

List<Bar> findByDriverIdAndStartTimeGreaterThanEqualAndEndTimeLessThanEqual(String id, Date start, Date end, Pageable pageable);

Notice that in this case, you shouldn't expose the other endpoints, and only expose this default method.