Apache NetBeansHow can I scan a classpath to find all classes of a particular type?
Prerequisites
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find the ClassPath on which the subtypes should be found. Use e.g. ClassPath.getClassPath(<file>, ClassPath.SOURCE)
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if the supertype is given as a FQN, convert to ElementHandle<TypeElement> via ElementHandle.create inside a Task or CancellableTask.
Finding all subtypes of given type
All subtypes of a given type on a given ClassPath can be found using ClassIndex. As ClassIndex contains only direct subtypes, the indirect subtypes need to be found on the client side:
private Set<ElementHandle<TypeElement>> findAllSubTypes(ClassPath on, ElementHandle<TypeElement> of) {
ClasspathInfo cpInfo = ClasspathInfo.create(ClassPath.EMPTY, ClassPath.EMPTY, on);
List<ElementHandle<TypeElement>> todo = new LinkedList<ElementHandle<TypeElement>>(of);
Set<ElementHandle<TypeElement>> result = new HashSet<ElementHandle<TypeElement>>();
while (!todo.isEmpty()) {
//TODO: if cancellable, check for cancel here
ElementHandle<TypeElement> curr = todo.remove(0);
result.add(curr);
Set<ElementHandle<TypeElement>> typeElements = cpInfo.getClassIndex().getElements(eh, EnumSet.of(ClassIndex.SearchKind.IMPLEMENTORS), EnumSet.of(ClassIndex.SearchScope.SOURCE));
if (typeElements != null) { //can be null for cancellable tasks
todo.addAll(typeElements);
}
}
return result;
}
