Jandex 3.2.0

An annotation overlay was added to Jandex. This is a layer on top of core Jandex that allows overriding annotations. This is useful when Jandex is used as a language model and annotations are used directly as framework metadata.

In fact, there are two annotation overlays: a default AnnotationOverlay, which is immutable, and a MutableAnnotationOverlay.

The default annotation overlay accepts an IndexView and a collection of AnnotationTransformations. These transformations are applied lazily, whenever the annotation overlay is first asked for annotation information of any particular declaration.

The mutable annotation overlay only accepts an IndexView and annotations may be added and removed freely, until the overlay is frozen. When it’s frozen, a list of annotation transformations is returned so that a corresponding immutable annotation overlay may be constructed.

In case you’re familiar with the AnnotationStore from from ArC or from RESTEasy Reactive, this is the very same concept, but the implementation is improved.

Support for sealed classes was added. This includes two methods: ClassInfo.isSealed() and ClassInfo.permittedSubclasses(). If a class is declared sealed, the isSealed() method returns true and the permittedSubclasses() method returns the names of permitted subclasses. To inspect them further, they must be looked up from the index.

Together with this, the ClassInfo.isFinal() and ClassInfo.isAbstract() methods were also added, as a shortcut for the corresponding Modifier methods called on ClassInfo.flags().

An empty index (EmptyIndex.INSTANCE or IndexView.empty()) was added. This is a very lightweight implementation of the IndexView interface that always returns null or an empty collection.

Further, a StackedIndex was also added. This is a new implementation of a composite index, which actually has well defined semantics in case the same class is present in the index multiple times (unlike CompositeIndex, which didn’t define this situation at all). In a stacked index, if a class is seen in one of the indexes, it is completely ignored in other indexes below the first one.

The behavior of Index.getKnownUsers() was improved. Previously, this method only considered a class as a user of another class when a reference to the other class was listed in the constant pool. Since this Jandex version, a class is also considered as a user of another class when the other class is present in the signature of the class or any of its members.

By default, the Jandex Maven plugin will not produce an index for a module with the POM packaging. This is a tiny breaking change that shouldn’t affect anyone, but in case it does, the <skipForPomPackaging> configuration option may be set to false to revert to the previous behavior.

And last but not least, hash table collisions were significantly reduced when interning type variable references. This should make indexing a lot faster in certain cases. Thanks Patrick Reinhart for the issue!

If you experience any troubles, or if you have any ideas for Jandex improvements, please file an issue.