Inventory

Inventory observes the latest client inventory or open container and can select a hotbar slot or click a container slot. Install the inventory unit and Session dependency, or explicitly select the default capability unit.

Wait for a supplied item

This fragment uses ScenarioContext anvil and a connected SimulatedPlayer alice on the first-test Paper server. Start with a fresh player whose inventory is empty. Import:

import me.whereareiam.anvil.capability.inventory.Inventory;
import java.time.Duration;

Then give an item and wait for an inventory update:

Inventory inventory = alice.capability(Inventory.class);
anvil.processes().server("server").console().sendCommand("give Alice minecraft:stone 1");
var snapshot = inventory.matching(
		state -> state.getItems().stream().anyMatch(item -> item.getAmount() > 0),
		Duration.ofSeconds(10)
);

This proves the previously empty inventory received an item. It does not identify that item as stone. Each InventoryItem carries a slot, protocol item ID, amount, and optional textual identifier. The bundled MCProtocol adapter supplies protocol IDs and amounts; its identifier is currently absent. Do not assume a numeric protocol ID is stable across Minecraft versions.

Select a slot or click a menu

inventory.selectSlot(0) selects the first hotbar slot; valid values are 0..8. For a plugin that opens a known menu, first wait for its expected slot content, then click that slot. This fragment assumes int expectedMenuItemProtocolId comes from your fixture for the selected native version and identifies the item the menu places in slot 4:

inventory.matching(state -> state.getContainerId() != 0
		&& state.getItems().stream().anyMatch(item -> item.getSlot() == 4
				&& item.getProtocolId() == expectedMenuItemProtocolId
				&& item.getAmount() > 0), Duration.ofSeconds(10));
inventory.click(4, InventoryClick.LEFT, 0);

Import me.whereareiam.anvil.capability.inventory.type.InventoryClick. The menu must already have been opened by your plugin's command or interaction, and slot 4 must be the action your test intends to exercise. Then wait for the plugin's result, such as a message or changed inventory.

An open-screen packet can produce a nonzero container ID before its content arrives. Waiting for the expected item prevents a click against that initial empty snapshot.

Click modes include LEFT, RIGHT, SHIFT_LEFT, HOTBAR_SWAP, DROP_ONE, and DROP_STACK. For HOTBAR_SWAP, the third argument is the hotbar slot 0 to 8, or 40 to swap with the off hand; use zero for the other modes.

Interpret snapshots

snapshot() reads immediately. matching(predicate, timeout) waits for a matching state. Both describe client-observed data, not a full server inventory API. The adapter uses its latest received container state when sending a click, so wait for the intended container before acting. Crafting automation is outside this capability's scope.

The snapshot follows the container the server last opened or filled. Slot updates for other containers and for the cursor do not change it. A change the server addresses to the player's own inventory by inventory index instead of a container slot updates the snapshot only while the player's inventory container (ID 0) is the observed one, at that index's slot in the container.

Behavior across Minecraft versions

Inventory works on every Minecraft version the MCProtocol library supports.