import java.util.List;
import java.util.concurrent.*;
import java.util.concurrent.StructuredTaskScope.Joiner;
import java.util.concurrent.StructuredTaskScope.Subtask;

/** A custom Joiner as written for JDK 26: two type parameters and onTimeout(). */
public class OldJoiner<T> implements Joiner<T, List<T>> {
    private final java.util.Queue<T> results = new ConcurrentLinkedQueue<>();
    public boolean onComplete(Subtask<T> s) { if (s.state() == Subtask.State.SUCCESS) results.add(s.get()); return false; }
    public void onTimeout() { }
    public List<T> result() { return List.copyOf(results); }
}