Flow.Processor for Operation submission

[Douglas Surber]

After reading the JavaDoc it’s not clear to me that onNext cannot throw. The JavaDoc says “the resulting behavior is not guaranteed” but it doesn’t say that onNext cannot throw. Can you point to something that has more detail?

Douglas


> On Oct 12, 2017, at 7:33 AM, Douglas Surber <douglas.surber at oracle.com> wrote:
> 
> Thanks for the correction with regard to onNext.
> 
>> On Oct 11, 2017, at 3:54 PM, Dávid Karnok <akarnokd at gmail.com <mailto:akarnokd at gmail.com>> wrote:
>> 
>>> Calling Subscription.onNext with any
>>>  * Operation that is not a member of this OperationGroup, that is
>>>  * was not created by calling one of the Operation factory methods on this
>>>  * OperationGroup, will throw IllegalArgumentException.
>> 
>> Processor.onNext must not throw, therefore an invalid onNext item should cancel the Subscription and signal onError to the Publisher side of the Processor.
>> 
>>> Still thinking about how to publish rows.
>> 
>> In rxjava-jdbc, ResultSet is used as a lambda parameter and the instance shown to the lambda should not escape it, i.e.,
>> 
>> <T> Flow.Publisher<T> convert(Function<Row, T> mapper);
>> 
>> 2017-10-11 22:05 GMT+02:00 Douglas Surber <douglas.surber at oracle.com <mailto:douglas.surber at oracle.com> <mailto:douglas.surber at oracle.com <mailto:douglas.surber at oracle.com>>>:
>> I have found what at first glance appears to be a non-hacky way to use Flow to channel Operations to an OperationGroup. It’s not perfect. The limitation that published Operations must be member Operations of the Operation group is unfortunate but absolutely necessary. Otherwise I think it is ok.
>> 
>> Delete Connection.onSubscribe.
>> 
>> Add the following to OperationGroup:
>> 
>>  /**
>>   * Returns a Flow.Processor that subscribes to a sequence of Operations and
>>   * publishes a sequence of corresponding Submissions. The Operations must
>>   * be members of this OperationGroup. Calling Subscription.onNext with any
>>   * Operation that is not a member of this OperationGroup, that is
>>   * was not created by calling one of the Operation factory methods on this
>>   * OperationGroup, will throw IllegalArgumentException. The method
>>   * Subscription.onNext will call submit on each Operation it is passed
>>   * and publish the resulting Submission. Since an Operation can only be
>>   * submitted once, submitting an Operation and calling onNext with that
>>   * submitted Operation will throw IllegalStateException.
>>   *
>>   * Each call to this method returns a new Flow.processor. The Submissions
>>   * published to each Processor are exactly those generated by calling
>>   * submit on the Operations passed as arguments to onNext on the same Processor.
>>   *
>>   * Note: If any Operation is submitted directly, that is by calling submit
>>   * rather than passing it to onNext, the Submission returned by the submit
>>   * call will not be published.
>>   *
>>   * @return a Flow.Processor that accepts Operations and generates Submissions
>>   */
>>  public Flow.Processor<Operation<T>, Submission<T>> operationProcessor();
>> 
>> Comments?
>> 
>> Still thinking about how to publish rows.
>> 
>> 
>> Douglas
>> 
>> 
>> 
>> -- 
>> Best regards,
>> David Karnok