@JeffQuesado_twitter welcome to gitter, did you solve your java9 module issue?
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@niloc132 the code is from 2013. I don't remember exactly anymore what was the reason. Yeah we have our own base64 implementation. But If I remember correctly the problem was in ABase64.createString(byte[] bytes) which only uses new String(bytes, IStandardEncoding.STANDARD_ENCODING)
public static String createString(byte[] bytes) throws UnsupportedEncodingException {
return new String(bytes, IStandardEncoding.STANDARD_ENCODING);
}I also remember that System.arraycopy() was always slow in GWT. But this seems to be fixed in the trunk now.
Very similar the code :)
Is there any way to send an arraybuffer (provided through JS File API, wrapped into an Uint8Array) via GWT-RPC as byte array?
I got a workaround for this
@JeffQuesado_twitter Thanks, yes that would work although I am trying to avoid copying given that the file might be large.
this is gwt 2.8.2 code, hence mixing and matching Any[]/JsArray<Any>, and exposes an api to JS, so i have to deal with arbitrary functions that they can pass in, and memoize large amounts of ticking data from the server
yeah sure, but copying just to get an array that GWT knows about seems overkill. I mean Uint8Array is already what I want, it is just that GWT-RPC does not know it can be accessed and treated like a byte[]. But I think I decided against GWT-RPC and use plain XMLHttpRequest2 + FormData. That would also give access to progress events during upload.
the other fix is what @rdeangelis83 suggested, make a wrapper object that has a byte[] field, and populate that manually
(and serialize as string base64, since you can't write binary, you have to do utf-8)
for "zero copy" you have to pass the entire buffer right to fetch/xhr
It must be FormData since the file has some additional information attached and I don't want to make two requests. Going low level is just a bit inconvenient that's why I thought to make it work with GWT-RPC. But I totally forgot upload progress. @niloc132 does your GWT-RPC implementation emit progress events?
@jnehlmeier no, but trivial to add - the serialization is separate from the "remote service" endpoint generation, which is still separate from the actual "how do i send", so reimplementing your fetch or xhr wrapper is a dozen lines of code, and will be generic with any given endpoint
interestingly, when we moved from gwt-rpc to grpc (with flatbuffer headers and arrow buf payloads, ostensibly zero copy) for reading data, we noticed about a 5% perf improvement for ~30k row tables, but then again instead of entirely auto-generated deserialization, i had to rewrite everything by hand
i was expecting a way bigger improvement since doing it all by hand meant less copies, more direct code (less indirection etc)
the dominating perf issue is still "longs suck", but large rapidly ticking charts get their updates promptly, so in the end it barely mattered
(the lesson: measure, then cut)
@niloc132 Heya! Seems the vertispan cert has expired (check https://repo.vertispan.com/gwt-snapshot/org/gwtproject/i18n/gwt-datetimeformat/1.0-SNAPSHOT/maven-metadata.xml)
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.. in GWT ~3 that is
Either use
Intl.DateTimeFormat through JsInterop, or have a look at https://github.com/treblereel/gwt-datetime (available on Vertispan's repository)
right now in my work i need maybe all gwt3 modules, so i forked them https://github.com/treblereel/gwtproject and published to my private repo
having a jdk preview doesn't help us, we need solid support in JDT (not just a preview, for example)
if you are just iterating the contents of the byte[], you can just do a Js.uncheckedCast to get from either to byte[] (but not vice versa)
if however you are actually serializing this via gwt-rpc or doing anything else which will call array.getClass() and expect a
byte[] type back, then you must instantiate the byte[] in java and copy the values over
@norzak can you clarify on what you're trying to do? if you're saying that you did want the "turn byte[] into typedarray" (i'm not quite sure what you were saying there), you might be able to find a way, such as creating a typed array, casting to byte[], populating it through something, and then consuming it that way
but it will really depend on what exactly you had in mind
(and as ever, measure, then cut, the naive implementation of what you're thinking on might already be pretty good)
@niloc132 sorry for the late reply. I think what I have is already the only way to implement using GWT on array conversions. On the other hand, I hit a very peculiar exception today. Knowing JavaScript is not a concurrent runtime, I am getting an interesting "Uncaught Error: java.util.ConcurrentModificationException" on my compiled javaScript application. How is that event possible? probably the iterator of the array list, very interesting.