public abstract class Visitor<T, R> {
private boolean isDone;
private ConcurrentLinkedQueue<R> founds = New.concurrentLinkedQueue();
public abstract void visit(T value);
public boolean isDone() {
return isDone;
}
public void done() {
this.isDone = true;
}
public void add(R found) {
this.founds.add(found);
}
public R getFirst() {
if (founds.isEmpty()) return null;
return founds.peek();
}
public ConcurrentLinkedQueue<R> getFounds() {
return founds;
}
}
