}
        }
    }

    static class OutputPropertySpec {
        File root
        TreeType treeType

        OutputPropertySpec(File root, TreeType treeType) {
            this.treeType = treeType
            this.root = root
        }
    }

    static OutputPropertySpec outputDirectorySpec(File dir) {
        return new OutputPropertySpec(dir, TreeType.DIRECTORY)
    }