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.flowable;

import org.reactivestreams.Publisher;

import io.reactivex.Flowable;
import io.reactivex.internal.functions.ObjectHelper;
import io.reactivex.internal.fuseable.HasUpstreamPublisher;

Abstract base class for operators that take an upstream source Publisher. 
Type parameters:
<T> – the upstream value type
<R> – the output value type/**
 * Abstract base class for operators that take an upstream
 * source {@link Publisher}.
 *
 * @param <T> the upstream value type
 * @param <R> the output value type
 */
abstract class AbstractFlowableWithUpstream<T, R> extends Flowable<R> implements HasUpstreamPublisher<T> {

    
The upstream source Publisher.
/**
     * The upstream source Publisher.
     */
    protected final Flowable<T> source;

    
Constructs a FlowableSource wrapping the given non-null (verified)
source Publisher.
Params:
source – the source (upstream) Publisher instance, not null (verified)/**
     * Constructs a FlowableSource wrapping the given non-null (verified)
     * source Publisher.
     * @param source the source (upstream) Publisher instance, not null (verified)
     */
    AbstractFlowableWithUpstream(Flowable<T> source) {
        this.source = ObjectHelper.requireNonNull(source, "source is null");
    }

    @Override
    public final Publisher<T> source() {
        return source;
    }
}