Re: Chainvayler

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Nice write-up! Thanks for sharing.

Cheers,
Justin

On Wed, Apr 22, 2020 at 11:36 PM hakan eryargi <[email protected]>
wrote:

> Hey guys,
>
> Remember my PoC project *Postvayler* many years ago? It was making POJOs
> persistent transparently based on @annotations and of course Prevayler.
>
> Recently I took the idea one step forward and extended the mechanism to
> also replicate POJOs among JVMs.
>
> Here is my blog post about it:
>
> https://medium.com/@hakan.eryargi/transparent-replication-and-persistence-for-pojo-graphs-805d9ae0f776
>
>
> Here is the project *Chainvayler* itself:
> https://github.com/raftAtGit/Chainvayler
>
> Personally I find the idea really promising :)
>
> Cheers,
> Hakan (r a f t)
>
> PS: I'm somehow got out from the email list, re-registered myself.
>
> On Mon, Dec 2, 2013 at 12:12 AM hakan eryargi <[email protected]>
> wrote:
>
>> i'm experimenting with the idea. so far not bad. just put what I've done
>> to GitHub. any suggestions, critics and contributions are welcome:)
>> https://github.com/raftAtGit/Postvayler
>>
>> apologies for the name, it sounded like a nice word play:)
>>
>> to run the sample, run the Compiler class
>> with raft.postvayler.samples.bank.Bank argument and then run
>> raft.postvayler.samples.bank.Main
>>
>> how it works:
>> compiler injects bytecode to root class and all @Persistent classes that
>> can be accesible* from root.
>>
>> root class contains an injected object pool, where each @Persistent class
>> is assigned a Long id and put into this object pool when created. this pool
>> will be* a WeakValueMap so objects which are not attached to root will be
>> garbage collected at some time.
>>
>> each @Persist method in a @Persistent class is instrumented like this:
>> @Persist
>> ReturnType doSomething(someParams) {..}
>>
>> doSomehing is copied to __postvayler__doSomething(..). the original doSomehing
>> becomes:
>>
>> ReturnType doSomething(someParams) {
>>     if (!there is postvayler context)
>>         return __postvayler__doSomething(..);
>>     if (we are in a prevayler transaction)
>>         return __postvayler__doSomething(..);
>>     return prevayler.execute(new MethodTransaction(..));
>> }
>>
>> the arguments to doSomehing(..) is transformed in MethodTransaction such
>> that references to @Persistent objects are replaced with Reference's,
>> which will later be restored from object pool. seems as this also solves
>> the Baptism problem.
>>
>> looks good to me for now:)
>>
>> cheers,
>> *r a f t*
>>
>> * not implemented yet
>>
>> On Wed, Nov 27, 2013 at 11:07 AM, Naveen Chawla <[email protected]>
>> wrote:
>>
>>> Sure, here:
>>> http://docs.oracle.com/javase/tutorial/java/generics/methods.html
>>>
>>> As for consistency, any multi-changes explicitly synchronized over
>>> prevalentObject can be auto-batched.
>>>
>>>
>>> On 27 November 2013 00:25, Klaus Wuestefeld <[email protected]> wrote:
>>>
>>>> > It is ordinary generic method syntax.
>>>>
>>>> Could you point me to some doc on this syntax? I couldnt find it here:
>>>> http://docs.oracle.com/javase/tutorial/extra/generics/methods.html
>>>>
>>>> > The beginning and end of a transaction would simply be any change to
>>>> any
>>>> > non-transient field.
>>>>
>>>> Suppose a transaction needs to update two fields to be correct but the
>>>> system crashes after the first. Will the system not be inconsistent on
>>>> recovery?
>>>>
>>>> Klaus
>>>>
>>>

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<div dir=3D"ltr"><div>Nice=C2=A0write-up! Thanks for sharing.</div><div><br=
></div><div>Cheers,</div><div>Justin</div><br><div class=3D"gmail_quote"><d=
iv dir=3D"ltr" class=3D"gmail_attr">On Wed, Apr 22, 2020 at 11:36 PM hakan =
eryargi &lt;<a href=3D"mailto:[email protected]">hakan.eryargi@gmail.=
com</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"marg=
in:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1e=
x"><div dir=3D"ltr"><div dir=3D"ltr"><div>Hey guys,</div><div><br></div><di=
v>Remember my PoC project <b>Postvayler</b> many years=C2=A0ago? It was mak=
ing POJOs persistent transparently based on=C2=A0@annotations and of course=
 Prevayler.</div><div><br></div><div>Recently I took the idea one step forw=
ard and extended the mechanism to also replicate POJOs among JVMs.</div><di=
v><br></div><div>Here is my blog post about it:</div><div><a href=3D"https:=
//medium.com/@hakan.eryargi/transparent-replication-and-persistence-for-poj=
o-graphs-805d9ae0f776" target=3D"_blank">https://medium.com/@hakan.eryargi/=
transparent-replication-and-persistence-for-pojo-graphs-805d9ae0f776</a>=C2=
=A0</div><div><br></div><div>Here is the project <b>Chainvayler</b> itself:=
=C2=A0<br></div><div><a href=3D"https://github.com/raftAtGit/Chainvayler" t=
arget=3D"_blank">https://github.com/raftAtGit/Chainvayler</a>=C2=A0</div><d=
iv><br></div><div>Personally I find the idea really promising :)</div><div>=
<br></div><div>Cheers,</div><div>Hakan (r a f t)=C2=A0</div><div><br></div>=
<div>PS: I&#39;m somehow got out from the email list, re-registered myself.=
</div></div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_=
attr">On Mon, Dec 2, 2013 at 12:12 AM hakan eryargi &lt;<a href=3D"mailto:h=
[email protected]" target=3D"_blank">[email protected]</a>&gt; w=
rote:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0p=
x 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=
=3D"ltr">i&#39;m experimenting with the idea. so far not bad. just put what=
 I&#39;ve done to GitHub. any suggestions, critics and contributions are we=
lcome:)<div><a href=3D"https://github.com/raftAtGit/Postvayler" target=3D"_=
blank">https://github.com/raftAtGit/Postvayler</a></div>
<div><br></div><div>apologies for the name, it=C2=A0sounded like a nice wor=
d play:)<br></div><div><br></div><div><div>to run the sample, run the Compi=
ler class with=C2=A0raft.postvayler.samples.bank.Bank argument and then run=
 raft.postvayler.samples.bank.Main</div>
<div><br></div><div>how it works:</div><div>compiler injects bytecode to ro=
ot class and all @Persistent=C2=A0classes that can be accesible* from root.=
=C2=A0</div><div><div class=3D"gmail_extra"><br></div><div class=3D"gmail_e=
xtra">root class contains an injected object pool, where each @Persistent c=
lass is assigned a Long id and put into this object pool when created. this=
 pool will be* a WeakValueMap so objects which are not attached to root wil=
l be garbage collected at some time.</div>
<div class=3D"gmail_extra"><br></div><div class=3D"gmail_extra">each @Persi=
st method in a=C2=A0@Persistent class is instrumented like this:</div><div =
class=3D"gmail_extra"><font face=3D"courier new, monospace">@Persist</font>=
</div><div class=3D"gmail_extra">
<font face=3D"courier new, monospace">ReturnType doSomething(someParams) {.=
.}</font></div><div class=3D"gmail_extra"><br></div><div class=3D"gmail_ext=
ra"><font face=3D"courier new, monospace">doSomehing </font>is copied to <f=
ont face=3D"courier new, monospace">__postvayler__doSomething(..)</font>. t=
he original <font face=3D"courier new, monospace">doSomehing </font>becomes=
:<br>
</div><div class=3D"gmail_extra"><br></div><div class=3D"gmail_extra"><font=
 face=3D"courier new, monospace">ReturnType=C2=A0doSomething(someParams) {<=
/font></div><div class=3D"gmail_extra"><font face=3D"courier new, monospace=
">=C2=A0 =C2=A0 if (!there is postvayler context)=C2=A0</font></div>
<div class=3D"gmail_extra"><font face=3D"courier new, monospace">=C2=A0 =C2=
=A0 =C2=A0 =C2=A0 return __postvayler__doSomething(..);</font></div><div cl=
ass=3D"gmail_extra"><font face=3D"courier new, monospace">=C2=A0 =C2=A0 if =
(we are in a prevayler transaction)=C2=A0</font></div>
<div class=3D"gmail_extra"><font face=3D"courier new, monospace">=C2=A0 =C2=
=A0 =C2=A0 =C2=A0 return __postvayler__doSomething(..);</font></div><div cl=
ass=3D"gmail_extra"><font face=3D"courier new, monospace">=C2=A0 =C2=A0 ret=
urn prevayler.execute(new MethodTransaction(..));</font></div>
<div class=3D"gmail_extra"><font face=3D"courier new, monospace">}<br></fon=
t></div><div class=3D"gmail_extra"><br></div><div class=3D"gmail_extra">the=
 arguments to doSomehing(..) is transformed in <font face=3D"courier new, m=
onospace">MethodTransaction </font>such that references to @Persistent obje=
cts are replaced with <font face=3D"courier new, monospace">Reference&#39;<=
/font><font face=3D"arial, helvetica, sans-serif">s</font>, which will late=
r be restored from object pool. seems as this also solves the Baptism probl=
em.=C2=A0</div>
<div class=3D"gmail_extra"><br></div><div class=3D"gmail_extra">looks good =
to me for now:)</div><div class=3D"gmail_extra"><br></div><div class=3D"gma=
il_extra">cheers,</div><div class=3D"gmail_extra"><i>r a f t</i></div><div =
class=3D"gmail_extra">
<br></div><div class=3D"gmail_extra">* not implemented yet</div><div class=
=3D"gmail_extra"><br><div class=3D"gmail_quote">On Wed, Nov 27, 2013 at 11:=
07 AM, Naveen Chawla <span dir=3D"ltr">&lt;<a href=3D"mailto:naveen.chwl@gm=
ail.com" target=3D"_blank">[email protected]</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-=
left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr">Sure, he=
re:=C2=A0<a href=3D"http://docs.oracle.com/javase/tutorial/java/generics/me=
thods.html" target=3D"_blank">http://docs.oracle.com/javase/tutorial/java/g=
enerics/methods.html</a><div>
<br></div><div>As for consistency, any multi-changes explicitly synchronize=
d over prevalentObject can be auto-batched.</div>
</div><div><div><div class=3D"gmail_extra"><br><br><div class=3D"gmail_quot=
e">On 27 November 2013 00:25, Klaus Wuestefeld <span dir=3D"ltr">&lt;<a hre=
f=3D"mailto:[email protected]" target=3D"_blank">[email protected]</a>&gt;</span>=
 wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-=
left:1px solid rgb(204,204,204);padding-left:1ex">
<div>&gt; It is ordinary generic method syntax.<br>
<br>
</div>Could you point me to some doc on this syntax? I couldnt find it here=
:<br>
<a href=3D"http://docs.oracle.com/javase/tutorial/extra/generics/methods.ht=
ml" target=3D"_blank">http://docs.oracle.com/javase/tutorial/extra/generics=
/methods.html</a><br>
<div><br>
&gt; The beginning and end of a transaction would simply be any change to a=
ny<br>
&gt; non-transient field.<br>
<br>
</div>Suppose a transaction needs to update two fields to be correct but th=
e<br>
system crashes after the first. Will the system not be inconsistent on<br>
recovery?<br>
<div><div><br>
Klaus</div></div></blockquote></div></div></div></div></blockquote></div></=
div></div></div></div></blockquote></div></div>
</blockquote></div></div>

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