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/**
* 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.observables;
import io.reactivex.Observable;
import io.reactivex.annotations.Nullable;
/**
* An {@link Observable} that has been grouped by key, the value of which can be obtained with {@link #getKey()}.
*
* Note: A {@link GroupedObservable} will cache the items it is to emit until such time as it
* is subscribed to. For this reason, in order to avoid memory leaks, you should not simply ignore those
* {@code GroupedObservable}s that do not concern you. Instead, you can signal to them that they
* may discard their buffers by applying an operator like {@link Observable#take take}{@code (0)} to them.
*
* @param
* the type of the key
* @param
* the type of the items emitted by the {@code GroupedObservable}
* @see Observable#groupBy(io.reactivex.functions.Function)
* @see ReactiveX documentation: GroupBy
*/
public abstract class GroupedObservable extends Observable {
final K key;
/**
* Constructs a GroupedObservable with the given key.
* @param key the key
*/
protected GroupedObservable(@Nullable K key) {
this.key = key;
}
/**
* Returns the key that identifies the group of items emitted by this {@code GroupedObservable}.
*
* @return the key that the items emitted by this {@code GroupedObservable} were grouped by
*/
@Nullable
public K getKey() {
return key;
}
}