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/**
* Copyright 2014 Netflix, Inc.
*
* 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 rx.observables;
import rx.Observable;
import rx.Subscriber;
import rx.functions.Func1;
/**
* 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}{@code (0)} to them.
*
* @param
* the type of the key
* @param
* the type of the items emitted by the {@code GroupedObservable}
* @see Observable#groupBy(Func1)
* @see RxJava Wiki: groupBy() and groupByUntil()
* @see RxJava Wiki: pivot()
*/
public class GroupedObservable extends Observable {
private final K key;
/**
* Converts an {@link Observable} into a {@code GroupedObservable} with a particular key.
*
* @param key
* the key to identify the group of items emitted by this {@code GroupedObservable}
* @param o
* the {@link Observable} to convert
* @return a {@code GroupedObservable} representation of {@code o}, with key {@code key}
*/
public static GroupedObservable from(K key, final Observable o) {
return new GroupedObservable(key, new OnSubscribe() {
@Override
public void call(Subscriber s) {
o.unsafeSubscribe(s);
}
});
}
public GroupedObservable(K key, OnSubscribe onSubscribe) {
super(onSubscribe);
this.key = key;
}
/**
* Returns the key that identifies the group of items emited by this {@code GroupedObservable}
*
* @return the key that the items emitted by this {@code GroupedObservable} were grouped by
*/
public K getKey() {
return key;
}
}