/*
 * Copyright (c) 2011-2017 Pivotal Software Inc, All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package reactor.core.publisher;

import reactor.core.CoreSubscriber;
import reactor.core.Fuseable;
import reactor.core.publisher.FluxTake.TakeFuseableSubscriber;

Takes only the first N values from the source Publisher.

If N is zero, the subscriber gets completed if the source completes, signals an error or
signals its first value (which is not not relayed though).
Type parameters:
<T> – the value type
See Also:
Reactive-Streams-Commons/**
 * Takes only the first N values from the source Publisher.
 * <p>
 * If N is zero, the subscriber gets completed if the source completes, signals an error or
 * signals its first value (which is not not relayed though).
 *
 * @param <T> the value type
 * @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
 */
final class FluxTakeFuseable<T> extends InternalFluxOperator<T, T> implements Fuseable {

	final long n;

	FluxTakeFuseable(Flux<? extends T> source, long n) {
		super(source);
		if (n < 0) {
			throw new IllegalArgumentException("n >= 0 required but it was " + n);
		}
		this.n = n;
	}

	@Override
	public CoreSubscriber<? super T> subscribeOrReturn(CoreSubscriber<? super T> actual) {
		return new TakeFuseableSubscriber<>(actual, n);
	}

	@Override
	public Object scanUnsafe(Attr key) {
		if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
		return super.scanUnsafe(key);
	}
}