/**
* 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.internal.operators;
import java.util.HashSet;
import java.util.Set;
import rx.Observable.Operator;
import rx.Subscriber;
import rx.functions.Func1;
/**
* Returns an Observable that emits all distinct items emitted by the source.
*
* @param <T> the value type
* @param <U> the key type
*/
public final class OperatorDistinct<T, U> implements Operator<T, T> {
final Func1<? super T, ? extends U> keySelector;
public OperatorDistinct(Func1<? super T, ? extends U> keySelector) {
this.keySelector = keySelector;
}
@Override
public Subscriber<? super T> call(final Subscriber<? super T> child) {
return new Subscriber<T>(child) {
Set<U> keyMemory = new HashSet<U>();
@Override
public void onNext(T t) {
U key = keySelector.call(t);
if (keyMemory.add(key)) {
child.onNext(t);
} else {
request(1);
}
}
@Override
public void onError(Throwable e) {
keyMemory = null;
child.onError(e);
}
@Override
public void onCompleted() {
keyMemory = null;
child.onCompleted();
}
};
}
}