}

    /**
     * This is final - override {@link #visitContents(FileCollectionStructureVisitor)} instead to provide the contents.
     */
    @Override
    public final void visitStructure(FileCollectionStructureVisitor visitor) {
        if (visitor.startVisit(OTHER, this)) {
            visitContents(visitor);
        }
    }

    protected void visitContents(FileCollectionStructureVisitor visitor) {

        return this;
    }

    private void calculateFinalizedValue() {
        ImmutableList.Builder<FileCollectionInternal> builder = ImmutableList.builder();
        value.visitContents(child -> child.visitStructure(new FileCollectionStructureVisitor() {
            @Override
            public void visitCollection(Source source, Iterable<File> contents) {