Java – include null check in mongorepository query by example

I tried to use mongorepository to find everything from a collection that meets specific search criteria using the following method:

<S extends T> Page<S> findAll(Example<S> example,Pageable pageable);

To do this, I'm building an examplematcher for all the fields included in the search like this:

private ExampleMatcher buildMatcher(FormSearchParameters formSearchParameters) {

    ExampleMatcher exampleMatcher = ExampleMatcher.matching()

            .withIgnorePaths("f1","f2","f3","f4","f5");

    if (!StringUtils.isEmpty(formSearchParameters.getName())) {
        exampleMatcher = exampleMatcher.withMatcher("name",match -> match.regex());
    }

    if (!StringUtils.isEmpty(formSearchParameters.getFoo())) {
        exampleMatcher = exampleMatcher.withMatcher("foo",matcher -> matcher.exact().ignoreCase());
    }

    if (null != formSearchParameters.getFilter()) {
        exampleMatcher = exampleMatcher.withMatcher("filter",matcher -> matcher.exact());
    }
    else {
        exampleMatcher = exampleMatcher.withIgnorePaths("filter");
    }

    return exampleMatcher.withIncludeNullValues();
}

But I need to add a last check that the field (such as nullfield) is empty I can't seem to find any information in the documentation about how to solve this problem

I tried to add the following nullfield to the sample model provided, but this seems to be ignored

.withMatcher("nullField",matcher -> matcher.exact())

Thank you.

Solution

According to the documentation, the scope of null processing setting is examplematcher (not property path) So, to make a long story short, you can't