#Class cast exception in networking for yoursalvation

1 messages · Page 1 of 1 (latest)

tacit sundial
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helpings

flat sleet
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Perfect

upbeat token
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hello

tacit sundial
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Class cast exception in networking for yoursalvation

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Okay so

flat sleet
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Could u resend your code real quick for me?

tacit sundial
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it seems as if whenever you're calling onReceive you're passing in an instance of ForwardedPacket instead of FindPlayerPacket

upbeat token
flat sleet
tacit sundial
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FindPlayerPacket, ForwadedPacket and the Command @upbeat token

flat sleet
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^ (again)

tacit sundial
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can you print what packet is when onReceive is called

upbeat token
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okay

tacit sundial
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Actually

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where are you calling onReceive

flat sleet
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Replace Find player packet with ForwardedPacket

tacit sundial
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Ah no I know, when a packet is received you're passing in that packet to onReceive, but you're receiving ForwardedRedisPacket and you actually want the packet inside of that

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you need to check if the received packet is an instance of ForwardedRedisPacket and if it is use the packet inside of that

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i.e. before calling onReceive

flat sleet
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The issue is that you call redis publish with a forwarded packet, which then in turn calls all onReceive's which in your case is only accepting FindPlayerPacket. The generics seem a bit messed up

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Feels like typescript

tacit sundial
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LOL

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fr

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@upbeat token basically

you send a ForwardedRedisPacket
you receive a ForwardedRedisPacket and try to pass it to the original ForwardedReidsPacket, which is only accepting FindPlayerPacket

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in the case you receive a ForwardedRedisPacket you want to pass to onReceive the packet inside the ForwardedRedisPacket

flat sleet
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You can also just accept RedisPacket<?> If no something else doesn't work because of generics, would be the easiest fix. Then just cast to a ForwardedPacket if applicable

tacit sundial
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I mean either that or cast in the listener

flat sleet
tacit sundial
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but that tightly couples the listener to the ForwardedRedisPacket

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You can, instead, remove the generic from the onReceive and do as follows

flat sleet
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It's a bit confusing when multiple people give multiple answers to your problem, so just listen to @tacit sundial and you're set

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Good luck 🤞

upbeat token
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okay thank you

tacit sundial
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public void onReceive(RedisPacket<?> packet) {
  if(!(packet instanceof ForwardedRedisPacket<?>)) return;
  ForwardedRedisPacket<?> forwarded = (ForwardedRedisPacket<?>) packet;
  if(this.packet.getClass() != forwarded.packet.getClass()) return; // Wrong packet, probably handle the error

  this.packet.onReceive((P) forwarded.packet);
  this.processData((P) forwarded.packet);
}
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Actually wait

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Tight coupling should be avoided

tacit sundial
upbeat token
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yes?

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i know understood the issue

tacit sundial
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That code should fix your issue

upbeat token
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im trying to find a solution that doesnt involve instanceof

tacit sundial
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You need the instanceof only there

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otherwise the rest of your code stays the same

upbeat token
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im pretty sure there is a way without instanceof

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but thank you :)

tacit sundial
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There isn't

upbeat token
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without you two i would have been stuck

tacit sundial
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You need that one instanceof there

upbeat token
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pretty sure taht will work

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or am i wrong?

tacit sundial
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uhhh

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Yeah no if the received packet is not a ForwardedRedisPacket then that will crash

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that is why I used the instanceof

upbeat token
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it wont crash

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the receiver takes everything

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it doesnt care

tacit sundial
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It will crash

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The compiler says it's fine, but it might not be at runtime

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also why are you so against one instanceof

upbeat token
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because then i would need to write this boilerplate code for every implementation

tacit sundial
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no

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You wouldn't

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You're just checking there when receiving the packet if it is a ForwardedRedisPacket, and ignoring all other received packets if the receiver is a ForwardedRedisPacket