eCAP

When to call noteAbContentAvailable()?

Asked by joe

wat is the best to control this noteAbContentAvailable() from the adapter sample you have if (!buffer.empty())
to trigger the noteAbContentAvailable what will happen if we take of -->if (!buffer.empty()) is it safe or ??
what about using if (receivingVb == opOn) instead

void Adapter::Xaction::abMake()
{
 Must(sendingAb == opUndecided); // have not yet started or decided not to send
 Must(hostx->virgin().body()); // that is our only source of ab content

 // we are or were receiving vb
 Must(receivingVb == opOn || receivingVb == opComplete);

 sendingAb = opOn;
 if (!buffer.empty())
  hostx->noteAbContentAvailable();
}

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Alex Rousskov (rousskov) said : 		#1

Your adapter transaction should call noteAbContentAvailable() when and only when both of the following two conditions become true:

1. the host application wants the adapter transaction to provide adapted body bytes
2. the adapter transaction is ready to provide adapted body bytes [that the host application was not informed about before]

In the sample code you pasted, condition #1 is satisfied by being inside the abMake() call, while condition #2 is determined by testing whether the buffer is empty.

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joe (joejoe) said : 		#2

so receivingVb == opOn == notify the code there is data can be received right
 and receivingVb == opComplete == finish resiving so can get more
in this case both i can use for detection to call hostx->noteAbContentAvailable(); ??

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Alex Rousskov (rousskov) said : 		#3

> receivingVb == opOn == notify the code there is data can be received right

In the modifying adapter sample, when receivingVb value is opOn, the adapter is expecting noteVb*() calls.

> and receivingVb == opComplete == finish resiving so can get more

When receivingVb value is opComplete, the adapter is not expecting more noteVb*() calls (but was expecting them at some time in the past).

You can find answers to questions like that by searching for "receivingVb = " expressions in the sample sources.

> both i can use for detection to call hostx->noteAbContentAvailable(); ??

I doubt it is a good idea to use [changes in] receivingVb state as the primary condition for calling noteAbContentAvailable(). You should call noteAbContentAvailable() when the two conditions I listed in my earlier answer become true. The changes in receivingVb state do not directly change or influence those two conditions AFAICT.

You might be trying to find a well-defined sequence of steps to receive and then send a body. There is no such sequence. Instead, there is a process/activity of receiving a virgin body and another process/activity of sending an adapted body. The two can be related, but it often helps to think of them as separate/independent processes/activities [with a couple of synchronization points in most cases].

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joe (joejoe) said : 		#4

tks alex