/*
 * 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 org.reactivestreams.Subscription;
import reactor.core.CorePublisher;
import reactor.core.CoreSubscriber;
import reactor.core.Fuseable;
import reactor.util.annotation.Nullable;

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:
/** * 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 FluxMap<T, R> extends InternalFluxOperator<T, R> { final Function<? super T, ? extends R> mapper;
Constructs a FluxMap instance with the given source and mapper.
Params:
  • source – the source Publisher instance
  • mapper – the mapper function
Throws:
/** * Constructs a FluxMap 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. */
FluxMap(Flux<? 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 MapConditionalSubscriber<>(cs, mapper); } return new MapSubscriber<>(actual, mapper); } @Override public Object scanUnsafe(Attr key) { if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC; return super.scanUnsafe(key); } static final class MapSubscriber<T, R> implements InnerOperator<T, R> { final CoreSubscriber<? super R> actual; final Function<? super T, ? extends R> mapper; boolean done; Subscription s; MapSubscriber(CoreSubscriber<? super R> actual, Function<? super T, ? extends R> mapper) { this.actual = actual; this.mapper = mapper; } @Override public void onSubscribe(Subscription s) { if (Operators.validate(this.s, s)) { this.s = s; actual.onSubscribe(this); } } @Override public void onNext(T t) { if (done) { Operators.onNextDropped(t, actual.currentContext()); return; } R v; try { v = Objects.requireNonNull(mapper.apply(t), "The mapper returned a null value."); } catch (Throwable e) { Throwable e_ = Operators.onNextError(t, e, actual.currentContext(), s); if (e_ != null) { onError(e_); } else { s.request(1); } return; } actual.onNext(v); } @Override public void onError(Throwable t) { if (done) { Operators.onErrorDropped(t, actual.currentContext()); return; } done = true; actual.onError(t); } @Override public void onComplete() { if (done) { return; } done = true; actual.onComplete(); } @Override @Nullable public Object scanUnsafe(Attr key) { if (key == Attr.PARENT) return s; if (key == Attr.TERMINATED) return done; if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC; return InnerOperator.super.scanUnsafe(key); } @Override public CoreSubscriber<? super R> actual() { return actual; } @Override public void request(long n) { s.request(n); } @Override public void cancel() { s.cancel(); } } static final class MapConditionalSubscriber<T, R> implements Fuseable.ConditionalSubscriber<T>, InnerOperator<T, R> { final Fuseable.ConditionalSubscriber<? super R> actual; final Function<? super T, ? extends R> mapper; boolean done; Subscription s; MapConditionalSubscriber(Fuseable.ConditionalSubscriber<? super R> actual, Function<? super T, ? extends R> mapper) { this.actual = actual; this.mapper = mapper; } @Override public void onSubscribe(Subscription s) { if (Operators.validate(this.s, s)) { this.s = s; actual.onSubscribe(this); } } @Override public void onNext(T t) { if (done) { Operators.onNextDropped(t, actual.currentContext()); return; } R v; try { v = Objects.requireNonNull(mapper.apply(t), "The mapper returned a null value."); } catch (Throwable e) { Throwable e_ = Operators.onNextError(t, e, actual.currentContext(), s); if (e_ != null) { onError(e_); } else { s.request(1); } return; } actual.onNext(v); } @Override public boolean tryOnNext(T t) { if (done) { Operators.onNextDropped(t, actual.currentContext()); return true; } R v; try { v = Objects.requireNonNull(mapper.apply(t), "The mapper returned a null value."); return actual.tryOnNext(v); } catch (Throwable e) { Throwable e_ = Operators.onNextError(t, e, actual.currentContext(), s); if (e_ != null) { done = true; actual.onError(e_); return true; } else { return false; } } } @Override public void onError(Throwable t) { if (done) { Operators.onErrorDropped(t, actual.currentContext()); return; } done = true; actual.onError(t); } @Override public void onComplete() { if (done) { return; } done = true; actual.onComplete(); } @Override @Nullable public Object scanUnsafe(Attr key) { if (key == Attr.PARENT) return s; if (key == Attr.TERMINATED) return done; if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC; return InnerOperator.super.scanUnsafe(key); } @Override public CoreSubscriber<? super R> actual() { return actual; } @Override public void request(long n) { s.request(n); } @Override public void cancel() { s.cancel(); } } }