Copyright (c) 2016-present, RxJava Contributors.
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
http://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.
/**
 * Copyright (c) 2016-present, RxJava Contributors.
 *
 * 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
 *
 * http://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 io.reactivex.internal.operators.observable;

import io.reactivex.*;
import io.reactivex.annotations.Nullable;
import io.reactivex.functions.Consumer;
import io.reactivex.internal.observers.BasicFuseableObserver;

Calls a consumer after pushing the current item to the downstream.
History: 2.0.1 - experimental
Type parameters:
<T> – the value type
Since:
2.1/**
 * Calls a consumer after pushing the current item to the downstream.
 * <p>History: 2.0.1 - experimental
 * @param <T> the value type
 * @since 2.1
 */
public final class ObservableDoAfterNext<T> extends AbstractObservableWithUpstream<T, T> {

    final Consumer<? super T> onAfterNext;

    public ObservableDoAfterNext(ObservableSource<T> source, Consumer<? super T> onAfterNext) {
        super(source);
        this.onAfterNext = onAfterNext;
    }

    @Override
    protected void subscribeActual(Observer<? super T> observer) {
        source.subscribe(new DoAfterObserver<T>(observer, onAfterNext));
    }

    static final class DoAfterObserver<T> extends BasicFuseableObserver<T, T> {

        final Consumer<? super T> onAfterNext;

        DoAfterObserver(Observer<? super T> actual, Consumer<? super T> onAfterNext) {
            super(actual);
            this.onAfterNext = onAfterNext;
        }

        @Override
        public void onNext(T t) {
            downstream.onNext(t);

            if (sourceMode == NONE) {
                try {
                    onAfterNext.accept(t);
                } catch (Throwable ex) {
                    fail(ex);
                }
            }
        }

        @Override
        public int requestFusion(int mode) {
            return transitiveBoundaryFusion(mode);
        }

        @Nullable
        @Override
        public T poll() throws Exception {
            T v = qd.poll();
            if (v != null) {
                onAfterNext.accept(v);
            }
            return v;
        }
    }
}