NumberIterablePublisher.java

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package org.reactivestreams.example.unicast;

import java.util.Collections;
import java.util.Iterator;
import java.util.concurrent.Executor;
import org.reactivestreams.Subscription;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Publisher;

public class NumberIterablePublisher extends AsyncIterablePublisher<Integer> {
    public NumberIterablePublisher(final int from, final int to, final Executor executor) {
        super(new Iterable<Integer>() {
          { if(from > to) throw new IllegalArgumentException("from must be equal or greater than to!"); }
          @Override public Iterator<Integer> iterator() {
            return new Iterator<Integer>() {
              private int at = from;
              @Override public boolean hasNext() { return at < to; }
              @Override public Integer next() {
                if (!hasNext()) return Collections.<Integer>emptyList().iterator().next();
                else return at++;
              }
              @Override public void remove() { throw new UnsupportedOperationException(); }
            };
          }
        }, executor);
    }
}