Hrm... I am interested in resetting the output state and
apparently that is not trivial to implement at this stage.
Let me see how far will my rescueJsonGeneratorState()
let me go. In the worst case, I will create a GitHub
issue for the feature.
BTW, in Utf8JsoGenerator#close(), I see a trick similar
to my rescueJsonGeneratorState():
/* 05-Dec-2008, tatu: To add [JACKSON-27], need to close open
* scopes.
*/
// First: let's see that we still have buffers...
if ((_outputBuffer != null)
&& isEnabled(Feature.AUTO_CLOSE_JSON_CONTENT)) {
while (true) {
JsonStreamContext ctxt = getOutputContext();
if (ctxt.inArray()) {
writeEndArray();
} else if (ctxt.inObject()) {
writeEndObject();
} else {
break;
}
}
}
Thanks so much for the help Tatu.
Really appreciated.
Keep up the good job!
On Monday, November 5, 2018 at 10:54:23 PM UTC+1, Tatu Saloranta wrote:
>
> On Fri, Oct 26, 2018 at 7:03 AM Volkan Yazıcı <volkan...@gmail.com
> <javascript:>> wrote:
> >
> > I can see that JsonGenerator keeps the door open for further input, that
> > indeed allows me to reuse it. (Thanks for the "root value separator"
> config,
> > did not know about it.) But that is also the reason I need to reach for
> > rescueJsonGeneratorState(). It would be really nice if I could have
> somehow
> > "reset" the state of JsonGenerator (which is actually Utf8JsonGenerator
> in
> > this particular case) and FilteringGeneratorDelegate. Then before each
> > serialization attempt, I can just reset my BB+generators and am ready to
> go.
>
> It would probably be easier to allow resetting of delegate type, but
> less so for regular generators.
>
> But I am still bit unclear on specific need: what part are you
> specifically hoping to reset?
> If it'd be output state (which Object/Array open etc), only close()
> would change that.
> But if you are thinking of underlying destination (OutputStream,
> Writer), buffering, those are not designed to be changed, and I
> wouldn't want to change that.
>
> Then again, if resetting of delegate (by changing target) was enough,
> that might be easy enough.
>
> -+ Tatu +-
>
> > On Friday, October 26, 2018 at 3:57:38 AM UTC+2, Tatu Saloranta wrote:
> >>
> >> On Wed, Oct 24, 2018 at 5:35 AM Volkan Yazıcı <volkan...@gmail.com>
> wrote:
> >> >
> >> > I am at the edge of making log4j2-logstash-layout gc-free. And at
> >> > this stage my only (GC) obstacle is the aforementioned two classes.
> >> > I need to instantiate them at each encode(LogEvent) call and this
> >> > spoils the entire gc-free magic.
> >> >
> >> > What I can do is create a ThreadLocal parade of
> ByteBufferOutputStream->JsonGenerator->FilteringGeneratorDelegate.
> >> > This allows me to implement encode() as follows:
> >> >
> >> > get ThreadLocal resources
> >> > reset BBOS
> >> > writeStartObject()
> >> > encode fields
> >> > writeEndObject()
> >> > flip and drain the BBOS to the Log4j BB sink
> >> >
> >> > Though this approach has an unfortunate showstopper: If the 4th step
> >> > leaves the JsonGenerator and/or the FilteringGeneratorDelegate in a
> >> > dirty state -- consider exceeding BBOS capacity, etc. -- all the
> >> > subsequent calls will fail.
> >> >
> >> > I will deeply appreciate any kind of help on this issue.
> >>
> >> Ah ok. Thank you for providing more information. This sounds like an
> >> interesting and useful challenge. :)
> >> I like to ask these things ("is that really necessary") first as I
> >> often learn something new.
> >>
> >> One thing that may be worth mentioning in case you weren't aware: you
> >> can just leave `JsonGenerator` open:
> >> it does not enforce that content consists of just a single JSON Value.
> >> In fact this is how many stream data generation
> >> (and parsing, via JsonParser) systems work.
> >> There is separate "root value separator" that is used between root
> >> values: it defaults to " " (single space), but may be
> >> reconfigured to, for example, linefeed.
> >>
> >> Whether this will work with FilteringGeneratorDelegate is bit
> >> different question.
> >>
> >> But do you think that reuse by not closing would work from processing
> >> perspective.
> >>
> >> -+ Tatu +-
> >>
> >>
> >>
> >>
> >> >
> >> > Best.
> >> >
> >> > On Monday, October 22, 2018 at 6:59:02 AM UTC+2, Tatu Saloranta
> wrote:
> >> >>
> >> >> On Sun, Oct 21, 2018 at 2:02 PM Volkan Yazıcı <volkan...@gmail.com>
> wrote:
> >> >> >
> >> >> > Hi,
> >> >> >
> >> >> > I have a JsonGenerator and FilteringGeneratorDelegate usage as
> follows:
> >> >> >
> >> >> > ByteArrayOutputStream outputStream =
> threadLocalOutputStreamRef.get();
> >> >> > try (JsonGenerator jsonGenerator =
> jsonFactory.createGenerator(outputStream)) {
> >> >> > try (JsonGenerator jsonGeneratorDelegate = new
> FilteringGeneratorDelegate(jsonGenerator, tokenFilter, true, true)) {
> >> >> > // ...
> >> >> > }
> >> >> > }
> >> >> >
> >> >> > Is it possible to reuse JsonGenerator and
> FilteringGeneratorDelegate instances in a way attached to the local thread
> context?
> >> >>
> >> >> No, JsonGenerator is designed for use-once life-cycle and does not
> >> >> support reuse.
> >> >> Instances are light-weight so there shouldn't usually be much
> benefit
> >> >> from attempting to reuse instances; same goes with
> >> >> FilteringGeneratorDelegate.
> >> >>
> >> >> -+ Tatu +-
> >> >
> >> > --
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