class CachingTokenFilter {
public final boolean incrementToken() throws IOException {
if (cache == null) {
// fill cache lazily
cache = new LinkedList();
fillCache();
iterator = cache.iterator();
}
if (!iterator.hasNext()) {
// the cache is exhausted, return false
return false;
}
// Since the TokenFilter can be reset, the tokens need to be preserved as immutable.
restoreState((AttributeSource.State) iterator.next());
return true;
}
}
