How to create cooldown use item
Code:
 

public class Ice_Sword extends SwordItem {
    public Ice_Sword(IItemTier tier, int attackDamageIn, float attackSpeedIn, Properties builderIn) {
        super(tier, attackDamageIn, attackSpeedIn, builderIn);
    }

    @Override
    public ActionResultType onItemUseFirst(ItemStack stack, ItemUseContext context) {
        World world = context.getWorld();

        if (!world.isRemote) {
            PlayerEntity playerEntity = Objects.requireNonNull(context.getPlayer());
            BlockState clickedBlock = world.getBlockState(context.getPos());

            rightClickOnCertainBlockState(clickedBlock, context, playerEntity);
            stack.damageItem(1, playerEntity, player -> player.sendBreakAnimation(context.getHand()));
        }

        return super.onItemUseFirst(stack, context);
    }

    private void rightClickOnCertainBlockState(BlockState clickedBlock, ItemUseContext context,
                                               PlayerEntity playerEntity) {
        boolean playerIsNotOnFire = !playerEntity.isBurning();

        if (random.nextFloat() > 1f) {
        } else if (playerIsNotOnFire && blockIsValidForResistance(clickedBlock)) {
            gainFireResistanceAndDestroyBlock(playerEntity, context.getWorld(), context.getPos());
        }
    }

    private boolean blockIsValidForResistance(BlockState clickedBlock) {
        return clickedBlock.getBlock() == Blocks.SAND;
    }

    private void gainFireResistanceAndDestroyBlock(PlayerEntity playerEntity, World world, BlockPos pos) {
        gainFireResistance(playerEntity);
        world.destroyBlock(pos, false);
        world.setBlockState(pos, Blocks.GLASS.getDefaultState());
    }

    public static void gainFireResistance(PlayerEntity playerEntity) {
        playerEntity.addPotionEffect(new EffectInstance(Effects.FIRE_RESISTANCE, 1, 100));
    }
}

 

You can use in your onItemUseFirst method:

playerEntity.getCooldowns().addCooldown(this, ticks);

Just replace ticks by the number of ticks you want the cooldown to last.

18 hours ago, steakmans said:

You can use in your onItemUseFirst method:

playerEntity.getCooldowns().addCooldown(this, ticks);

Just replace ticks by the number of ticks you want the cooldown to last.

works as a shield cooldown