Class AnvilUpdateEvent

src/main/java/net/minecraftforge/event/AnvilUpdateEvent.java:35–70

AnvilUpdateEvent is fired when a player places items in both the left and right slots of a anvil. If the event is canceled, vanilla behavior will not run, and the output will be set to null. If the event is not canceled, but the output is not null, it will set the output and not run vanilla behavior

 * if the output is null, and the event is not canceled, vanilla behavior will execute.
 */
@Cancelable
public class AnvilUpdateEvent extends Event
{
    @Nonnull
    private final ItemStack left;  // The left side of the input
    @Nonnull
    private final ItemStack right; // The right side of the input
    private final String name;     // The name to set the item, if the user specified one.
    @Nonnull
    private ItemStack output;      // Set this to set the output stack
    private int cost;              // The base cost, set this to change it if output != null
    private int materialCost; // The number of items from the right slot to be consumed during the repair. Leave as 0 to consume the entire stack.

    public AnvilUpdateEvent(@Nonnull ItemStack left, @Nonnull ItemStack right, String name, int cost)
    {
        this.left = left;
        this.right = right;
        this.output = ItemStack.EMPTY;
        this.name = name;
        this.setCost(cost);
        this.setMaterialCost(0);
    }

    @Nonnull
    public ItemStack getLeft() { return left; }
    @Nonnull
    public ItemStack getRight() { return right; }
    public String getName() { return name; }
    @Nonnull
    public ItemStack getOutput() { return output; }
    public void setOutput(@Nonnull ItemStack output) { this.output = output; }
    public int getCost() { return cost; }
    public void setCost(int cost) { this.cost = cost; }
    public int getMaterialCost() { return materialCost; }
    public void setMaterialCost(int materialCost) { this.materialCost = materialCost; }
}