本文整理了Java中rx.Observable.singleOrDefault()方法的一些代码示例，展示了Observable.singleOrDefault()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Observable.singleOrDefault()方法的具体详情如下：
包路径：rx.Observable
类名称：Observable
方法名：singleOrDefault
[英]Returns an Observable that emits the single item emitted by the source Observable, if that Observable emits only a single item, or a default item if the source Observable emits no items. If the source Observable emits more than one item, throw an IllegalArgumentException.
Scheduler: singleOrDefault does not operate by default on a particular Scheduler.
[中]如果源可观测对象仅发射单个项，则返回发射源可观测对象发射的单个项的可观测对象；如果源可观测对象未发射任何项，则返回默认项。如果源Observable发出多个项，则抛出IllegalArgumentException。
调度程序：默认情况下，singleOrDefault不会在特定调度程序上运行。
代码示例来源：origin: jooby-project/jooby
@Override
public <T> Observable<List<T>> query(final N1qlQuery query) {
return bucket.query(query)
.flatMap(aqr -> Observable.zip(aqr.rows().toList(),
aqr.errors().toList(),
aqr.finalSuccess().singleOrDefault(Boolean.FALSE),
(rows, errors, finalSuccess) -> {
if (!finalSuccess) {
throw new QueryExecutionException(
"execution of query resulted in exception: ",
Try.apply(() -> errors.get(0)).orElse(null));
}
List<T> value = new ArrayList<>();
for (AsyncN1qlQueryRow row : rows) {
try {
T v = converter.fromBytes(row.byteValue());
value.add(v);
} catch (IOException ex) {
throw new QueryExecutionException(
"execution of query resulted in exception", null, ex);
}
}
return value;
}));
}代码示例来源：origin: leeowenowen/rxjava-examples
@Override
public void run() {
Observable.<Integer>empty().singleOrDefault(10).subscribe(new Action1<Integer>() {
@Override
public void call(Integer integer) {
log(integer);
}
});
}
});代码示例来源：origin: alex-shpak/rx-jersey
@Override
public Single convert(Observable<?> result) throws Throwable {
return result.singleOrDefault(null).toSingle();
}
}代码示例来源：origin: com.netflix.rxjava/rxjava-core
/**
* Returns an Observable that emits only the very first item emitted by the source Observable, or a default
* item if the source Observable completes without emitting anything.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/Netflix/RxJava/images/rx-operators/firstOrDefault.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code firstOrDefault} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param defaultValue
* the default item to emit if the source Observable doesn't emit anything
* @return an Observable that emits only the very first item from the source, or a default item if the
* source Observable completes without emitting any items
* @see <a href="https://github.com/Netflix/RxJava/wiki/Filtering-Observables#firstordefault">RxJava wiki: firstOrDefault</a>
* @see "MSDN: Observable.firstOrDefaultAsync"
*/
public final Observable<T> firstOrDefault(T defaultValue) {
return take(1).singleOrDefault(defaultValue);
}代码示例来源：origin: com.netflix.rxjava/rxjava-core
/**
* Returns an Observable that emits only the last item emitted by the source Observable, or a default item
* if the source Observable completes without emitting any items.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/Netflix/RxJava/images/rx-operators/lastOrDefault.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code lastOrDefault} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param defaultValue
* the default item to emit if the source Observable is empty
* @return an Observable that emits only the last item emitted by the source Observable, or a default item
* if the source Observable is empty
* @see <a href="https://github.com/Netflix/RxJava/wiki/Filtering-Observables#lastordefault">RxJava wiki: lastOrDefault</a>
* @see "MSDN: Observable.lastOrDefaultAsync"
*/
public final Observable<T> lastOrDefault(T defaultValue) {
return takeLast(1).singleOrDefault(defaultValue);
}代码示例来源：origin: com.netflix.rxjava/rxjava-core
/**
* Returns an Observable that emits only the very first item emitted by the source Observable that satisfies
* a specified condition, or a default item if the source Observable emits no such items.
* <p>
* <img width="640" height="310" src="https://raw.github.com/wiki/Netflix/RxJava/images/rx-operators/firstOrDefaultN.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code firstOrDefault} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param predicate
* the condition any item emitted by the source Observable has to satisfy
* @param defaultValue
* the default item to emit if the source Observable doesn't emit anything that satisfies the
* {@code predicate}
* @return an Observable that emits only the very first item emitted by the source Observable that satisfies
* the {@code predicate}, or a default item if the source Observable emits no such items
* @see <a href="https://github.com/Netflix/RxJava/wiki/Filtering-Observables#firstordefault">RxJava wiki: firstOrDefault</a>
* @see "MSDN: Observable.firstOrDefaultAsync"
*/
public final Observable<T> firstOrDefault(T defaultValue, Func1<? super T, Boolean> predicate) {
return takeFirst(predicate).singleOrDefault(defaultValue);
}代码示例来源：origin: com.couchbase.client/java-client
@Override
public DesignDocument getDesignDocument(final String name, final long timeout, final TimeUnit timeUnit) {
return Blocking.blockForSingle(
asyncBucketManager.getDesignDocument(name).singleOrDefault(null), timeout, timeUnit
);
}代码示例来源：origin: com.netflix.rxjava/rxjava-core
/**
* If this {@code BlockingObservable} completes after emitting a single item that matches a predicate,
* return that item; if it emits more than one such item, throw an {@code IllegalArgumentException}; if it
* emits no items, return a default value.
* <p>
* <img width="640" height="315" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/B.singleOrDefault.p.png" alt="">
*
* @param defaultValue
* a default value to return if this {@code BlockingObservable} emits no matching items
* @param predicate
* a predicate function to evaluate items emitted by this {@code BlockingObservable}
* @return the single item emitted by the {@code BlockingObservable} that matches the predicate, or the
* default value if no such items are emitted
* @see <a href="https://github.com/ReactiveX/RxJava/wiki/Blocking-Observable-Operators#single-and-singleordefault">RxJava Wiki: singleOrDefault()</a>
* @see <a href="http://msdn.microsoft.com/en-us/library/system.reactive.linq.observable.singleordefault.aspx">MSDN: Observable.SingleOrDefault</a>
*/
public T singleOrDefault(T defaultValue, Func1<? super T, Boolean> predicate) {
return blockForSingle(o.filter(predicate).map(Functions.<T>identity()).singleOrDefault(defaultValue));
}代码示例来源：origin: com.couchbase.client/java-client
@Override
public DesignDocument getDesignDocument(final String name, final boolean development, final long timeout,
final TimeUnit timeUnit) {
return Blocking.blockForSingle(
asyncBucketManager.getDesignDocument(name, development).singleOrDefault(null), timeout, timeUnit
);
}代码示例来源：origin: com.couchbase.client/java-client
@Override
public BucketSettings getBucket(String name, long timeout, TimeUnit timeUnit) {
return Blocking.blockForSingle(asyncClusterManager.getBucket(name).singleOrDefault(null), timeout, timeUnit);
}代码示例来源：origin: com.netflix.rxjava/rxjava-core
/**
* If this {@code BlockingObservable} completes after emitting a single item, return that item; if it emits
* more than one item, throw an {@code IllegalArgumentException}; if it emits no items, return a default
* value.
* <p>
* <img width="640" height="315" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/B.singleOrDefault.png" alt="">
*
* @param defaultValue
* a default value to return if this {@code BlockingObservable} emits no items
* @return the single item emitted by this {@code BlockingObservable}, or the default value if it emits no
* items
* @see <a href="https://github.com/ReactiveX/RxJava/wiki/Blocking-Observable-Operators#single-and-singleordefault">RxJava Wiki: singleOrDefault()</a>
* @see <a href="http://msdn.microsoft.com/en-us/library/system.reactive.linq.observable.singleordefault.aspx">MSDN: Observable.SingleOrDefault</a>
*/
public T singleOrDefault(T defaultValue) {
return blockForSingle(o.map(Functions.<T>identity()).singleOrDefault(defaultValue));
}代码示例来源：origin: com.couchbase.client/java-client
@Override
public JsonDocument document(long timeout, TimeUnit timeUnit) {
return Blocking.blockForSingle(asyncViewRow.document().singleOrDefault(null), timeout, timeUnit);
}代码示例来源：origin: com.couchbase.client/java-client
@Override
public <D extends Document<?>> D document(Class<D> target, long timeout, TimeUnit timeUnit) {
return Blocking.blockForSingle(asyncViewRow.document(target).singleOrDefault(null), timeout, timeUnit);
}代码示例来源：origin: com.couchbase.client/java-client
@Override
public JsonDocument document(long timeout, TimeUnit timeUnit) {
return Blocking.blockForSingle(asyncViewRow.document().singleOrDefault(null), timeout, timeUnit);
}代码示例来源：origin: com.couchbase.client/java-client
@Override
public <D extends Document<?>> D document(Class<D> target, long timeout, TimeUnit timeUnit) {
return Blocking.blockForSingle(asyncViewRow.document(target).singleOrDefault(null), timeout, timeUnit);
}代码示例来源：origin: com.couchbase.client/java-client
/**
* Maps a raw {@link ViewQueryResponse} into a {@link AsyncViewResult}.
*
* @param bucket reference to the bucket.
* @param query the original query object.
* @param response the response from the server.
* @return a converted {@link AsyncViewResult}.
*/
public static Observable<AsyncViewResult> mapToViewResult(final AsyncBucket bucket, final ViewQuery query,
final ViewQueryResponse response) {
return response
.info()
.singleOrDefault(null)
.map(new ByteBufToJsonObject())
.map(new BuildViewResult(bucket, query, response));
}代码示例来源：origin: com.couchbase.client/java-client
/**
* Maps a raw {@link ViewQueryResponse} into a {@link AsyncSpatialViewResult}.
*
* @param bucket reference to the bucket.
* @param query the original query object.
* @param response the response from the server.
* @return a converted {@link AsyncSpatialViewResult}.
*/
public static Observable<AsyncSpatialViewResult> mapToSpatialViewResult(final AsyncBucket bucket,
final SpatialViewQuery query, final ViewQueryResponse response) {
return response
.info()
.singleOrDefault(null)
.map(new ByteBufToJsonObject())
.map(new BuildSpatialViewResult(bucket, query, response));
}代码示例来源：origin: nurkiewicz/rxjava-book-examples
default Observable<Integer> populationOf(String query) {
return search(query)
.concatMapIterable(SearchResult::getGeonames)
.map(Geoname::getPopulation)
.filter(p -> p != null)
.singleOrDefault(0)
.doOnError(th ->
log.warn("Falling back to 0 for {}", query, th))
.onErrorReturn(th -> 0)
.subscribeOn(Schedulers.io());
}代码示例来源：origin: com.couchbase.client/java-client
@Override
public Observable<AnalyticsQueryResult> call(final AsyncAnalyticsQueryResult aqr) {
final boolean parseSuccess = aqr.parseSuccess();
final String requestId = aqr.requestId();
final String clientContextId = aqr.clientContextId();
return Observable.zip(aqr.signature().singleOrDefault(JsonObject.empty()),
aqr.info().singleOrDefault(AnalyticsMetrics.EMPTY_METRICS),
aqr.errors().toList(),
aqr.status(),
aqr.finalSuccess().singleOrDefault(Boolean.FALSE),
new Func5<Object, AnalyticsMetrics, List<JsonObject>, String, Boolean, AnalyticsQueryResult>() {
@Override
public AnalyticsQueryResult call(Object signature, AnalyticsMetrics info, List<JsonObject> errors, String finalStatus, Boolean finalSuccess) {
return new DefaultAnalyticsQueryResult(aqr.handle(), signature, info, errors, finalStatus, finalSuccess,
parseSuccess, requestId, clientContextId);
}
});
}
};代码示例来源：origin: com.couchbase.client/java-client
@Override
public Observable<AnalyticsQueryResult> call(AsyncAnalyticsQueryResult aqr) {
final boolean parseSuccess = aqr.parseSuccess();
final String requestId = aqr.requestId();
final String clientContextId = aqr.clientContextId();
return Observable.zip(aqr.rows().toList(),
aqr.signature().singleOrDefault(JsonObject.empty()),
aqr.info().singleOrDefault(AnalyticsMetrics.EMPTY_METRICS),
aqr.errors().toList(),
aqr.status(),
aqr.finalSuccess().singleOrDefault(Boolean.FALSE),
new Func6<List<AsyncAnalyticsQueryRow>, Object, AnalyticsMetrics, List<JsonObject>, String, Boolean, AnalyticsQueryResult>() {
@Override
public AnalyticsQueryResult call(List<AsyncAnalyticsQueryRow> rows, Object signature,
AnalyticsMetrics info, List<JsonObject> errors, String finalStatus, Boolean finalSuccess) {
return new DefaultAnalyticsQueryResult(rows, signature, info, errors, finalStatus, finalSuccess,
parseSuccess, requestId, clientContextId);
}
});
}
};内容来源于网络，如有侵权，请联系作者删除！