private void registerTypeElement(String entityName, TypeElement element) {
        Set<TypeElement> elements = context.typeElements.computeIfAbsent(entityName, k -> new HashSet<TypeElement>());
        elements.add(element);
    }
{@code AbstractQuerydslProcessor} is the base class for Querydsl annotation processors and
contains the main processing logic. The subclasses just provide the configuration.

@author tiwe
querydsl-apt/src/main/java/com/querydsl/apt/AbstractQuerydslProcessor.java