Class Empty

src/jvm/clojure/lang/TransformerIterator.java:119–135

}

private static class Empty implements Buffer {
    public Buffer add(Object o) {
        return new Single(o);
    }

    public Object remove() {
        throw new IllegalStateException("Removing object from empty buffer");
    }

    public boolean isEmpty() {
        return true;
    }

    public String toString() {
        return "Empty";
    }
}

private static class Single implements Buffer {
    private volatile Object val;