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https://issues.apache.org/jira/browse/IGNITE-1439?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15978539#comment-15978539
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Igor Sapego edited comment on IGNITE-1439 at 4/21/17 11:22 AM:
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[~ptupitsyn] this design actually comes from the C++ itself to utilize it
destructor-based resource control. You may look at this this way:
{{SharedState}} is implementation of the needed functionality itself. This is
something you would call {{FutureImpl}} in Java.
{{Future}} class is something that provides public API (read access) and holds
shared pointer to implementation, thus preventing its destruction.
{{Promise}} class here is something for which you do not have analogue in
managed programming languages. Basically, it's guard-class, which holds shared
pointer to implementation just as {{Future}} but provides write access to it.
Its main role is to guarantee that that threads waiting on {{Future}} gets
released if something goes wrong - upon destruction it checks state of the
{{SharedState}} class and if it is not marked as a completed yet, it sets it to
error state, thus releasing all waiting threads.
As for naming - I used one which is commonly used in C++ community.
(http://www.cplusplus.com/reference/future/future,
http://www.cplusplus.com/reference/future/promise).
bq. Where does this come from? Windows XP is no longer supported even by
Microsoft.
https://apacheignite.readme.io/docs/getting-started#section-prerequisites
was (Author: isapego):
[~ptupitsyn] this design actually comes from the C++ itself to utilize it
destructor-based resource control. You may look at this this way:
{{SharedState}} is implementation of the needed functionality itself. This is
something you would call {{FutureImpl}} in Java. {{Future}} class is something
that provides public API (read access) and holds shared pointer to
implementation, thus preventing its destruction. The {{Promise}} class here is
something for which you do not have analogue in managed programming languages.
Basically, it's guard-class, which holds shared pointer to implementation just
as {{Future}} but provides write access to it. Its main role is to guarantee
that that threads waiting on {{Future}} gets released if something goes wrong -
upon destruction it checks state of the {{SharedState}} class and if it is not
marked as a completed yet it sets it to error state thus releasing all waiting
threads.
As for naming - I used one which is commonly used in C++ community.
(http://www.cplusplus.com/reference/future/future,
http://www.cplusplus.com/reference/future/promise).
bq. Where does this come from? Windows XP is no longer supported even by
Microsoft.
https://apacheignite.readme.io/docs/getting-started#section-prerequisites
> CPP: Implement futures.
> -----------------------
>
> Key: IGNITE-1439
> URL: https://issues.apache.org/jira/browse/IGNITE-1439
> Project: Ignite
> Issue Type: Task
> Components: platforms
> Affects Versions: 1.1.4
> Reporter: Vladimir Ozerov
> Assignee: Igor Sapego
> Labels: cpp
> Fix For: 2.1
>
>
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