https://github.com/ReactiveX/RxJava: Reactive Extensions for Java
  • David Karnok 
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;

import io.reactivex.annotations.*;


Interface to map/wrap a downstream observer to an upstream observer.

Type parameters:
  • <Downstream> – the value type of the downstream
  • <Upstream> – the value type of the upstream
/**
 * Interface to map/wrap a downstream observer to an upstream observer.
 *
 * @param <Downstream> the value type of the downstream
 * @param <Upstream> the value type of the upstream
 */
public interface ObservableOperator<Downstream, Upstream> {
    
Applies a function to the child Observer and returns a new parent Observer.

Params:
  • observer – the child Observer instance
Throws:
Returns:the parent Observer instance
/**
     * Applies a function to the child Observer and returns a new parent Observer.
     * @param observer the child Observer instance
     * @return the parent Observer instance
     * @throws Exception on failure
     */
    @NonNull
    Observer<? super Upstream> apply(@NonNull Observer<? super Downstream> observer) throws Exception;
}