---
title: Abstract progress item
---
Package: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;com.codex.composer.api.v1.item <br/>
Canonical Name: com.codex.composer.api.v1.item.AbstractProgressItem

Base class for items that have a multistep progress mechanic.

Each item tracks its current step in NBT and can produce a resulting item once fully completed.
Subclasses define the final item and any behavior when progress changes or completes.

Inheritors have to implement:
```java
/* Called when the item reaches its final step. Should return the item
   that represents the completed state. */
protected abstract ItemStack getCompletedItem(ItemStack oldStack);

/* Optional, empty by default */
void onProgressIncreased(ItemStack stack, PlayerEntity player, int newStep) {}
void onFinishProcess(ItemStack stack, World world, PlayerEntity player) {}
```
## Example Implementation
**From Mathematica, an unreleased CC:T addon for fabric.**
```java
public abstract class AbstractPolishableItem extends AbstractProgressItem {
    private final float failChance;

    public AbstractPolishableItem(Settings settings, int steps, float failChance) {... }

    public abstract ItemStack getShatteredItem(ItemStack stack);

    public ItemStack tryPolish(ItemStack stack, World world, PlayerEntity player) {
        if (Math.random() <= getFailChance()) {
            return getShatteredItem(stack);
        }

        return tryIncrementProgress(stack, world, player, 1);
    }

    public static ItemStack create(Item type, int step) {...}
    public float getFailChance() {...}

    @Override public void appendTooltip(ItemStack stack, @Nullable World world, List<Text> tooltip, TooltipContext context) {...}
}
```
----
```java
public class RoughPrismarineCrystal extends AbstractPolishableItem {
    public RoughPrismarineCrystal() {
        super(new Settings().maxCount(1), 5, 0.15f);
    }

    @Override
    protected ItemStack getCompletedItem(ItemStack itemStack) {
        return new ItemStack(ModItems.POLISHED_PRISMARINE_CRYSTAL);
    }

    @Override
    public ItemStack getShatteredItem(ItemStack stack) {
        return new ItemStack(ModItems.SHATTERED_PRISMARINE_CRYSTAL);
    }

    @Override
    public int getItemBarColor(ItemStack stack) { return 0x55FCD2; }
}