I need some help figuring out this java.lang.ArrayIndexOutOfBoundsException: 4

[TheRPGAdventurer]

I googled this before and it say that happens if you are calling an array in a restricted 

 

EnumDragonLifeStage: https://pastebin.com/RhcFuqw9

 

Crash

java.lang.ArrayIndexOutOfBoundsException: 4
	at com.TheRPGAdventurer.ROTD.server.entity.helper.EnumDragonLifeStage.fromTickCount(EnumDragonLifeStage.java:31)
	at com.TheRPGAdventurer.ROTD.server.entity.helper.DragonLifeStageHelper.getLifeStage(DragonLifeStageHelper.java:128)
	at com.TheRPGAdventurer.ROTD.server.entity.helper.DragonLifeStageHelper.updateLifeStage(DragonLifeStageHelper.java:278)
	at com.TheRPGAdventurer.ROTD.server.entity.helper.DragonLifeStageHelper.onLivingUpdate(DragonLifeStageHelper.java:267)
	at java.util.HashMap$Values.forEach(HashMap.java:972)
	at com.TheRPGAdventurer.ROTD.server.entity.EntityTameableDragon.func_70636_d(EntityTameableDragon.java:923)
	at net.minecraft.entity.EntityLivingBase.func_70071_h_(EntityLivingBase.java:2179)
	at net.minecraft.entity.EntityLiving.func_70071_h_(EntityLiving.java:295)
	at com.TheRPGAdventurer.ROTD.server.entity.EntityTameableDragon.func_70071_h_(EntityTameableDragon.java:847)
	at net.minecraft.world.World.func_72866_a(World.java:1993)
	at net.minecraft.world.WorldServer.func_72866_a(WorldServer.java:832)
	at net.minecraft.world.World.func_72870_g(World.java:1955)
	at net.minecraft.world.World.func_72939_s(World.java:1759)
	at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:613)
	at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:767)
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668)
	at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:185)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526)
	at java.lang.Thread.run(Thread.java:745)

To be fair i didnt write thi code thi wa written years ago im here to revive it.

Edited March 24, 2019 by TheRPGAdventurer

[DavidM]

    public static int clampTickCount(int ticksSinceCreation) {
        return MathHelper.clamp(ticksSinceCreation, 0, VALUES.length * TICKS_PER_STAGE);
    }
 
    public static EnumDragonLifeStage fromTickCount(int ticksSinceCreation) {
        return VALUES[clampTickCount(ticksSinceCreation) / TICKS_PER_STAGE];
    }

Your enum has only 4 elements; therefore, the maximum value for the index can only be 3.

However, in your clampTickCount, it clamps the value as if there are 5 elements in your enum (hint: off by one). 

 

Note that MathHelper#clamp is inclusive on both the min value and the max value.

Edited March 24, 2019 by DavidM

[TheRPGAdventurer]

so i have to put (

return MathHelper.clamp(ticksSinceCreation, 0, 5 * TICKS_PER_STAGE);

)

[TheRPGAdventurer]

or

/**
 * Returns the value of the first parameter, clamped to be within the lower and upper limits given by the second and
 * third parameters.
 */
public static int clamp(int num, int min, int max)
{
    if (num <= min)
    {
        return min;
    }
    else
    {
        return num >= max ? max : num;
    }
}

[DavidM]

VALUES.length is equal to 4, which, after multiplying and dividing by the same constant, still equals to 4.

 

Let's say we set the TICKS_PER_STAGE constant to 10, in which case

VALUES.length * TICKS_PER_STAGE

equals to 40.

40 divided by TICKS_PER_STAGE (10 in this case) is 4, which is out of bound for your enum.

 

However, if you change the return statement in your clampTickCount to:

return MathHelper.clamp(ticksSinceCreation, 0, (VALUES.length * TICKS_PER_STAGE) - 1);

, it will clamp everything into the range of [0, 39].

Now, the maximum return value is 39, which, after being divided by TICKS_PER_STAGE (10 in this case), is 3. This matches the highest dragon growth stage in your enum.

 

TL;DR:

Spoiler

Change your return statement in your clampTickCount to:

return MathHelper.clamp(ticksSinceCreation, 0, (VALUES.length * TICKS_PER_STAGE) - 1);