Creating multiple aliases for the same QueryDSL path in Spring Data

Question

I have a generic Spring Data repository interface that extends QuerydslBinderCustomizer, allowing me to customize the query execution. I am trying to extend the basic equality testing built into the default repository implementation, so that I can perform other query operations using Spring Data REST. For example:

GET /api/persons?name=Joe%20Smith  // This works by default
GET /api/persons?nameEndsWith=Smith  // This requires custom parameter binding.

The problem I am having is that every alias of an entity path I create seems to override the preceding alias bindings.

@NoRepositoryBean
public interface BaseRepository<T, ID extends Serializable>
    extends PagingAndSortingRepository<T, ID>, QueryDslPredicateExecutor<T>, QuerydslBinderCustomizer { 

    @Override
    @SuppressWarnings("unchecked")
    default void customize(QuerydslBindings bindings, EntityPath entityPath){

        Class<T> model = entityPath.getType();
        Path<T> root = entityPath.getRoot();
        for (Field field: model.getDeclaredFields()){
            if (field.isSynthetic()) continue;
            Class<?> fieldType = field.getType();
            if (fieldType.isAssignableFrom(String.class)){
                // This binding works by itself, but not after the next one is added
                bindings.bind(Expressions.stringPath(root, field.getName()))
                        .as(field.getName()  + "EndsWith")
                        .first((path, value) -> {
                            return path.endsWith(value);
                        });
                // This binding overrides the previous one
                bindings.bind(Expressions.stringPath(root, field.getName()))
                        .as(field.getName()  + "StartsWith")
                        .first((path, value) -> {
                            return path.startsWith(value);
                        });
            }
        }
    }
}

Is it possible to create more than one alias for the same field? Can this be accomplished in a generic way?

Answer 1

You can create a transient property bound to QueryDSL this way:

@Transient
@QueryType(PropertyType.SIMPLE)
public String getNameEndsWith() {
    // Whatever code, even return null
}

If you are using the QueryDSL annotation processor, you will see the "nameEndsWith" in the metadata Qxxx class, so you can bind it like any persisted property, but without persisting it.