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https://issues.apache.org/jira/browse/IGNITE-946?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14680788#comment-14680788
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Alexey Goncharuk edited comment on IGNITE-946 at 8/10/15 9:27 PM:
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In general, I do not like the current {{VersionedEntryEx}} interface. I think
it should have only one method {{IgniteVersion version()}}, and
{{IgniteVersion}} should have only {{updateTime}}. Other methods, such as
{{topologyVersion}} or let alone {{order}} are meaningless for a user.
Moreover, it is hard to implement the most straightforward use-case - check
whether the version of a cache entry has changed in between the user calls. In
order to do this one has to compare the results of all four methods.
{code}
public interface IgniteVersion {
long updateTime();
}
public interface VersionedEntry extends Cache.Entry {
IgniteVersion version();
}
{code}
The way I see it should work is represented in a snippet below:
{code}
IgniteVersion ver1 = entry.version();
// Optimistically assume that no updates will happen and do some business-logic
based on entry value.
...
refreshedEntry = getEntry(key);
IgniteVersion ver2 = refreshedEntry.version()
if (!ver1.equals(ver2)) {
// Entry has been concurrently updated.
}
{code}
Needless to say that an instance of versioned entry has to be immutable, so
that {{value()}} method will always be reflected by a correct {{version()}}.
was (Author: agoncharuk):
In general, I do not like the current {{VersionedEntryEx}} interface. I think
it should have only one method {{IgniteVersion version()}}, and
{{IgniteVersion}} should have only {{updateTime}}. Other methods, such as
{{topologyVersion}} or let alone {{order}} are meaningless for a user.
Moreover, it is hard to implement the most straightforward use-case - check
whether the version of a cache entry has changed in between the user calls. In
order to do this one has to compare the results of all four methods.
The way I see it should work is represented in a snippet below:
{code}
IgniteVersion ver1 = entry.version();
// Optimistically assume that no updates will happen and do some business-logic
based on entry value.
...
refreshedEntry = getEntry(key);
IgniteVersion ver2 = refreshedEntry.version()
if (!ver1.equals(ver2)) {
// Entry has been concurrently updated.
}
{code}
Needless to say that an instance of versioned entry has to be immutable, so
that {{value()}} method will always be reflected by a correct {{version()}}.
> Need to expose versioned cache entry to public API
> --------------------------------------------------
>
> Key: IGNITE-946
> URL: https://issues.apache.org/jira/browse/IGNITE-946
> Project: Ignite
> Issue Type: Bug
> Components: cache
> Affects Versions: sprint-4
> Reporter: Valentin Kulichenko
> Assignee: Denis Magda
> Priority: Critical
> Labels: Usability
> Fix For: ignite-1.4
>
> Attachments: ignite-946-2.patch, ignite-946-3.patch, ignite-946.patch
>
>
> Currently we have versioned entry, but it's not available on public API, but
> knowing version can be useful in some cases. Need to make it accessible via
> {{unwrap}} method.
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