/*
 * 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 java.util.Objects;
import java.util.function.Function;

import reactor.core.CoreSubscriber;
import reactor.core.Fuseable;

Maps the values of the source publisher one-on-one via a mapper function.
Type parameters:
<T> – the source value type
<R> – the result value type
See Also:
Reactive-Streams-Commons/**
 * Maps the values of the source publisher one-on-one via a mapper function.
 *
 * @param <T> the source value type
 * @param <R> the result value type
 * @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
 */
final class MonoMap<T, R> extends InternalMonoOperator<T, R> {

	final Function<? super T, ? extends R> mapper;

	
Constructs a StreamMap instance with the given source and mapper.
Params:
source – the source Publisher instance
mapper – the mapper function
Throws:
NullPointerException – if either source or mapper is null./**
	 * Constructs a StreamMap instance with the given source and mapper.
	 *
	 * @param source the source Publisher instance
	 * @param mapper the mapper function
	 * @throws NullPointerException if either {@code source} or {@code mapper} is null.
	 */
	MonoMap(Mono<? extends T> source, Function<? super T, ? extends R> mapper) {
		super(source);
		this.mapper = Objects.requireNonNull(mapper, "mapper");
	}

	@Override
	@SuppressWarnings("unchecked")
	public CoreSubscriber<? super T> subscribeOrReturn(CoreSubscriber<? super R> actual) {
		if (actual instanceof Fuseable.ConditionalSubscriber) {
			Fuseable.ConditionalSubscriber<? super R> cs = (Fuseable.ConditionalSubscriber<? super R>) actual;
			return new FluxMap.MapConditionalSubscriber<>(cs, mapper);
		}
		return new FluxMap.MapSubscriber<>(actual, mapper);
	}

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