[1.15.2] Removing Duration off of Potion Effects

[TheRedWaffle]

So basically I am trying to make a Mug of Milk remove 30seconds(600ticks) off of every potion effect the player has.
Though this causes a crash when I drink the item.

(The code is located in the onItemUseFinish function)

        if (!worldIn.isRemote) {
            entityLiving.getActivePotionEffects().stream().map(EffectInstance::getEffectInstance).forEach(effect -> {
                int duration = effect.getDuration();
                int amplifier = effect.getAmplifier();
                duration -= 600;
                Effect effectPotion = effect.getPotion();
                entityLiving.removeActivePotionEffect(effectPotion);
                entityLiving.addPotionEffect(new EffectInstance(effectPotion, duration, amplifier));
            });
        }

I looked it up already and it is because in my code I remove the potion effect and then try to access it.

Does anyone know a way around this?

Edited May 14, 2020 by TheRedWaffle
spelling

[TheRedWaffle]

Here's the error if any of you need it.

Spoiler

---- Minecraft Crash Report ----
// This doesn't make any sense!

Time: 14/05/20 2:54 PM
Description: Ticking player

java.util.ConcurrentModificationException: null
    at java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1633) ~[?:1.8.0_241] {}
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482) ~[?:1.8.0_241] {}
    at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472) ~[?:1.8.0_241] {}
    at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151) ~[?:1.8.0_241] {}
    at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174) ~[?:1.8.0_241] {}
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[?:1.8.0_241] {}
    at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418) ~[?:1.8.0_241] {}
    at com.theredwaffle.delicious_foods.items.MilkMugItem.onItemUseFinish(MilkMugItem.java:40) ~[?:?] {re:classloading}
    at net.minecraft.item.ItemStack.onItemUseFinish(ItemStack.java:213) ~[?:?] {re:classloading}
    at net.minecraft.entity.LivingEntity.onItemUseFinish(LivingEntity.java:2868) ~[?:?] {re:classloading}
    at net.minecraft.entity.player.ServerPlayerEntity.onItemUseFinish(ServerPlayerEntity.java:1025) ~[?:?] {re:classloading,pl:accesstransformer:B}
    at net.minecraft.entity.LivingEntity.updateActiveHand(LivingEntity.java:2746) ~[?:?] {re:classloading}
    at net.minecraft.entity.LivingEntity.tick(LivingEntity.java:2179) ~[?:?] {re:classloading}
    at net.minecraft.entity.player.PlayerEntity.tick(PlayerEntity.java:236) ~[?:?] {re:classloading,pl:accesstransformer:B}
    at net.minecraft.entity.player.ServerPlayerEntity.playerTick(ServerPlayerEntity.java:377) ~[?:?] {re:classloading,pl:accesstransformer:B}
    at net.minecraft.network.play.ServerPlayNetHandler.tick(ServerPlayNetHandler.java:183) ~[?:?] {re:classloading}
    at net.minecraft.network.NetworkManager.tick(NetworkManager.java:245) ~[?:?] {re:classloading}
    at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:148) ~[?:?] {re:classloading}
    at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:900) ~[?:?] {re:classloading,pl:accesstransformer:B}
    at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:818) ~[?:?] {re:classloading,pl:accesstransformer:B}
    at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:120) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:659) [?:?] {re:classloading,pl:accesstransformer:B}
    at java.lang.Thread.run(Thread.java:748) [?:1.8.0_241] {}

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Server thread
Stacktrace:
    at java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1633)
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
    at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
    at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
    at com.theredwaffle.delicious_foods.items.MilkMugItem.onItemUseFinish(MilkMugItem.java:40)
    at net.minecraft.item.ItemStack.onItemUseFinish(ItemStack.java:213)
    at net.minecraft.entity.LivingEntity.onItemUseFinish(LivingEntity.java:2868)
    at net.minecraft.entity.player.ServerPlayerEntity.onItemUseFinish(ServerPlayerEntity.java:1025)
    at net.minecraft.entity.LivingEntity.updateActiveHand(LivingEntity.java:2746)
    at net.minecraft.entity.LivingEntity.tick(LivingEntity.java:2179)
    at net.minecraft.entity.player.PlayerEntity.tick(PlayerEntity.java:236)

-- Player being ticked --
Details:
    Entity Type: minecraft:player (net.minecraft.entity.player.ServerPlayerEntity)
    Entity ID: 272
    Entity Name: Dev
    Entity's Exact location: 185.70, 67.00, 148.83
    Entity's Block location: World: (185,67,148), Chunk: (at 9,4,4 in 11,9; contains blocks 176,0,144 to 191,255,159), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
    Entity's Momentum: 0.00, -0.08, 0.00
    Entity's Passengers: []
    Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
    at net.minecraft.entity.player.ServerPlayerEntity.playerTick(ServerPlayerEntity.java:377)
    at net.minecraft.network.play.ServerPlayNetHandler.tick(ServerPlayNetHandler.java:183)
    at net.minecraft.network.NetworkManager.tick(NetworkManager.java:245)

-- Ticking connection --
Details:
    Connection: net.minecraft.network.NetworkManager@6d25cff6
Stacktrace:
    at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:148)
    at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:900)
    at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:818)
    at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:120)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:659)
    at java.lang.Thread.run(Thread.java:748)

-- System Details --
Details:
    Minecraft Version: 1.15.2
    Minecraft Version ID: 1.15.2
    Operating System: Windows 10 (amd64) version 10.0
    Java Version: 1.8.0_241, Oracle Corporation
    Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 957315352 bytes (912 MB) / 1887436800 bytes (1800 MB) up to 3782737920 bytes (3607 MB)
    CPUs: 12
    JVM Flags: 1 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump
    ModLauncher: 5.0.0-milestone.4+67+b1a340b
    ModLauncher launch target: fmluserdevclient
    ModLauncher naming: mcp
    ModLauncher services: 
        /eventbus-2.0.0-milestone.1-service.jar eventbus PLUGINSERVICE 
        /forge-1.15.2-31.1.0_mapped_snapshot_20190719-1.14.3-launcher.jar object_holder_definalize PLUGINSERVICE 
        /forge-1.15.2-31.1.0_mapped_snapshot_20190719-1.14.3-launcher.jar runtime_enum_extender PLUGINSERVICE 
        /accesstransformers-2.0.0-milestone.1-shadowed.jar accesstransformer PLUGINSERVICE 
        /forge-1.15.2-31.1.0_mapped_snapshot_20190719-1.14.3-launcher.jar capability_inject_definalize PLUGINSERVICE 
        /forge-1.15.2-31.1.0_mapped_snapshot_20190719-1.14.3-launcher.jar runtimedistcleaner PLUGINSERVICE 
        /forge-1.15.2-31.1.0_mapped_snapshot_20190719-1.14.3-launcher.jar fml TRANSFORMATIONSERVICE 
    FML: 31.1
    Forge: net.minecraftforge:31.1.0
    FML Language Providers: 
        javafml@31.1
        minecraft@1
    Mod List: 
        client-extra.jar Minecraft {minecraft@1.15.2 DONE}
        main Delicious Foods Mod {delicious-foods@1.15.2-1.0.0 DONE}
        forge-1.15.2-31.1.0_mapped_snapshot_20190719-1.14.3-recomp.jar Forge {forge@31.1.0 DONE}
    Player Count: 1 / 8; [ServerPlayerEntity['Dev'/272, l='New World', x=185.70, y=67.00, z=148.83]]
    Data Packs: vanilla, mod:delicious-foods, mod:forge (incompatible)
    Type: Integrated Server (map_client.txt)
    Is Modded: Definitely; Client brand changed to 'forge'

 

[Draco18s]

12 minutes ago, TheRedWaffle said:

ConcurrentModificationException

You can't modify an array while iterating over it.

[Vinyarion]

19 minutes ago, Draco18s said:

You can't modify an array while iterating over it.

Half true: if you want to remove-while-iterating, you will want to get the Collection's Iterator (Collection<T>: public default Iterator<T> iterator()). Iterators may or may not support element removal like this:
 

if (!thingCollection.isEmpty()) {
  Iterator<Thing> itr = thingCollection.iterator();
  do {
    Thing thing = itr.next();
    if (shouldRemove(thing)) {
      itr.remove();
    }
  } while (itr.hasNext());
}

`Collection<T>` also should have a `default void removeIf(Predicate<T> returnTrueToRemove)` method that is more amenable to lambdas like you seem to want to use here (lambdas are really great like that, keep using them)

Edited May 14, 2020 by Vinyarion
removeIf

[TheRedWaffle]

1 hour ago, Vinyarion said:

Half true: if you want to remove-while-iterating, you will want to get the Collection's Iterator (Collection<T>: public default Iterator<T> iterator()). Iterators may or may not support element removal like this:
 

if (!thingCollection.isEmpty()) {
  Iterator<Thing> itr = thingCollection.iterator();
  do {
    Thing thing = itr.next();
    if (shouldRemove(thing)) {
      itr.remove();
    }
  } while (itr.hasNext());
}

`Collection<T>` also should have a `default void removeIf(Predicate<T> returnTrueToRemove)` method that is more amenable to lambdas like you seem to want to use here (lambdas are really great like that, keep using them)

 

Sweet thanks for the help.
Do I need to make my own 'shouldRemove()' method?
I have this right now but shouldRemove isn't a real method
 

        if (!worldIn.isRemote) {
            if (!entityLiving.getActivePotionEffects().isEmpty()) {
                Iterator<EffectInstance> itr = entityLiving.getActivePotionEffects().iterator();
                do {
                    EffectInstance effectInstance = itr.next();

                    int duration = effectInstance.getDuration();
                    int amplifier = effectInstance.getAmplifier();
                    duration -= 600;
                    Effect effectPotion = effectInstance.getPotion();

                    if(shouldRemove(effectInstance)) {
                        entityLiving.removeActivePotionEffect(effectPotion);
                        entityLiving.addPotionEffect(new EffectInstance(effectPotion, duration, amplifier));
                    }

                } while (itr.hasNext());
            }
        }

Let me know if I have something wrong.

[TheThorneCorporation]

5 minutes ago, TheRedWaffle said:

 

Sweet thanks for the help.
Do I need to make my own 'shouldRemove()' method?
I have this right now but shouldRemove isn't a real method
 

        if (!worldIn.isRemote) {
            if (!entityLiving.getActivePotionEffects().isEmpty()) {
                Iterator<EffectInstance> itr = entityLiving.getActivePotionEffects().iterator();
                do {
                    EffectInstance effectInstance = itr.next();

                    int duration = effectInstance.getDuration();
                    int amplifier = effectInstance.getAmplifier();
                    duration -= 600;
                    Effect effectPotion = effectInstance.getPotion();

                    if(shouldRemove(effectInstance)) {
                        entityLiving.removeActivePotionEffect(effectPotion);
                        entityLiving.addPotionEffect(new EffectInstance(effectPotion, duration, amplifier));
                    }

                } while (itr.hasNext());
            }
        }

Let me know if I have something wrong.

Vinyarion doesn't actually mean "make a method called shouldRemove(EffectInstance e) that returns a boolean". the shouldRemove(object) expression is a stand in for whatever expression you want to use to determine if an object should be removed.

[TheRedWaffle]

1 minute ago, TheThorneCorporation said:

Vinyarion doesn't actually mean "make a method called shouldRemove(EffectInstance e) that returns a boolean". the shouldRemove(object) expression is a stand in for whatever expression you want to use to determine if an object should be removed.

Ugh I should have thought of that, sorry.

[TheRedWaffle]

Ok so everything works in game but the effect display doesn't visibly show the duration changing could this be because I instantly remove and change the effect?

 

Here's the code

        if (!worldIn.isRemote) {
            if (!entityLiving.getActivePotionEffects().isEmpty()) {
                Iterator<EffectInstance> itr = entityLiving.getActivePotionEffects().stream().iterator();
                do {
                    EffectInstance effectInstance = itr.next();

                    int duration = effectInstance.getDuration();
                    int amplifier = effectInstance.getAmplifier();
                    duration -= 600;
                    Effect effectPotion = effectInstance.getPotion();

                    entityLiving.removeActivePotionEffect(effectPotion);
                    entityLiving.addPotionEffect(new EffectInstance(effectPotion, duration, amplifier));

                } while (itr.hasNext());
            }
        }