Reimplement the 'single' operator #967
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…when the Observable is empty
…irstOrDefaultTest and OperatorLastTest
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RxJava-pull-requests #908 FAILURE |
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RxJava-pull-requests #909 FAILURE |
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RxJava-pull-requests #910 FAILURE |
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RxJava-pull-requests #917 SUCCESS |
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Thank you, @samueltardieu |
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RxJava-pull-requests #918 SUCCESS |
| @@ -4545,12 +4545,12 @@ public final void onNext(T args) { | |||
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| /** | |||
| * Returns an Observable that emits only the very first item emitted by the source Observable, or raises an | |||
| * {@code IllegalArgumentException} if the source Observable is empty. | |||
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It seems that it can still throw IllegalArgumentException if there are too many elements.
new IllegalArgumentException("Sequence contains too many elements")
So don't all of these Javadocs now need to include both IllegalArgumentException and NoSuchElementException?
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An Observable which has more than one element is valid for first and last. These two operator just fetch the first or the last one from the Observable. Only single requires that the Observable must contain exactly one element.
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Ah sorry, you do have both exceptions on some of the other methods where it applies. Nevermind!
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Waiting until Rx 0.18 since this is a breaking signature change (if dependent on the exception). |
This PR did the following work:
singleoperatorfirst,last,singleto rxjava-scalaObservableis empty,first,last,singlewill throwNoSuchElementExceptioninstead ofIllegalArgumentException. It's more consistent with the Java Collection API, e.g., Deque.getFirst(), Deque.getLast(). This will break the current APIs.