ItemStack builder with Functional Interfaces.

ItemBuilder.java

import org.bukkit.Material;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.meta.ItemMeta;

import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import java.util.function.BiConsumer;
import java.util.function.BiPredicate;
import java.util.function.Supplier;

public class ItemBuilder implements Supplier<ItemStack> {

    private final List<BiConsumer<ItemStack, ItemMeta>> biconsumerList;
    private final Material material;

    public ItemBuilder(Material material) {
        this.biconsumerList = new LinkedList<>();
        this.material = material;
    }

    public ItemBuilder with(BiConsumer<ItemStack, ItemMeta> biconsumer) {
        biconsumerList.add(biconsumer);
        return this;
    }

    public ItemBuilder withIf(BiPredicate<ItemStack, ItemMeta> bipredicate, BiConsumer<ItemStack, ItemMeta> biconsumer) {
        return with((stack, meta) -> {
            if (bipredicate.test(stack, meta)) {
                biconsumerList.add(biconsumer);
            }
        });
    }

    public ItemBuilder withIfOrElse(BiPredicate<ItemStack, ItemMeta> bipredicate, BiConsumer<ItemStack, ItemMeta> ifTrue, BiConsumer<ItemStack, ItemMeta> ifFalse) {
        return with((stack, meta) -> {
            if (bipredicate.test(stack, meta)) {
                biconsumerList.add(ifTrue);
                return;
            }
            biconsumerList.add(ifFalse);
        });
    }

    public ItemBuilder withAmount(int amount) {
        return with((stack, meta) -> stack.setAmount(amount));
    }

    public ItemBuilder withDurability(int durability) {
        return with((stack, meta) -> stack.setDurability((short) durability));
    }

    public ItemBuilder withLoreIf(BiPredicate<ItemStack, ItemMeta> bipredicate, String... lore) {
        return withIf(bipredicate, (stack, meta) -> meta.setLore(Arrays.asList(lore)));
    }

    public ItemBuilder withNameIfOrElse(BiPredicate<ItemStack, ItemMeta> bipredicate, String
            name, BiConsumer<ItemStack, ItemMeta> biconsumer) {
        return withIfOrElse(bipredicate, (stack, meta) -> meta.setDisplayName(name), biconsumer);
    }

    @Override
    public ItemStack get() {
        ItemStack item = new ItemStack(material);
        ItemMeta meta = item.getItemMeta();
        biconsumerList.forEach(biconsumer -> biconsumer.accept(item, meta));
        item.setItemMeta(meta);
        return item;
    }
}