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Reactive Extensions for Java
/*
* 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.rxjava3.internal.operators.observable;
import io.reactivex.rxjava3.annotations.Nullable;
import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.functions.*;
import io.reactivex.rxjava3.internal.observers.BasicFuseableObserver;
public final class ObservableDistinctUntilChanged extends AbstractObservableWithUpstream {
final Function keySelector;
final BiPredicate comparer;
public ObservableDistinctUntilChanged(ObservableSource source, Function keySelector, BiPredicate comparer) {
super(source);
this.keySelector = keySelector;
this.comparer = comparer;
}
@Override
protected void subscribeActual(Observer observer) {
source.subscribe(new DistinctUntilChangedObserver<>(observer, keySelector, comparer));
}
static final class DistinctUntilChangedObserver extends BasicFuseableObserver {
final Function keySelector;
final BiPredicate comparer;
K last;
boolean hasValue;
DistinctUntilChangedObserver(Observer actual,
Function keySelector,
BiPredicate comparer) {
super(actual);
this.keySelector = keySelector;
this.comparer = comparer;
}
@Override
public void onNext(T t) {
if (done) {
return;
}
if (sourceMode != NONE) {
downstream.onNext(t);
return;
}
K key;
try {
key = keySelector.apply(t);
if (hasValue) {
boolean equal = comparer.test(last, key);
last = key;
if (equal) {
return;
}
} else {
hasValue = true;
last = key;
}
} catch (Throwable ex) {
fail(ex);
return;
}
downstream.onNext(t);
}
@Override
public int requestFusion(int mode) {
return transitiveBoundaryFusion(mode);
}
@Nullable
@Override
public T poll() throws Throwable {
for (;;) {
T v = qd.poll();
if (v == null) {
return null;
}
K key = keySelector.apply(v);
if (!hasValue) {
hasValue = true;
last = key;
return v;
}
if (!comparer.test(last, key)) {
last = key;
return v;
}
last = key;
}
}
}
}