HUD Compatibility

GroupManager displays real-time group information on the player's HUD through integration with third-party HUD plugins.

Supported HUD Plugins

AutoMultiHud (by Buuz135)

GroupManager uses reflection to detect and integrate with AutoMultiHud. When available, group status is rendered as a HUD panel using the CSS selector #GroupMultiHUD.

AutoMultiHud intercepts all setCustomHud network packets and groups them by JAR source (via stack trace inspection). Each plugin that calls setCustomHud gets its own isolated "group" inside AutoMultiHud, allowing multiple plugins to display HUDs simultaneously without replacing each other.

MultipleHUD

Preferred HUD provider. GroupManager detects it at startup and uses it with highest priority. MultipleHUD manages HUD groups natively through its own API, avoiding the positioning conflicts that can occur when AutoMultiHud groups packets by JAR source.

Detection Order

1. MultipleHUD is checked first — if available, it is always used.
2. If not found, AutoMultiHud is detected (for compatibility and stale-state cleanup).
3. InternalMultiHud acts as the fallback — the HUD works without any external plugin.

Detection happens once at plugin startup. No configuration is needed.

HUD Content

The group HUD panel displays:

Element	Description
Group title	"Group" header with member count
Leader	Leader name highlighted
Members	All member names with online/offline indicators
Prefix/Suffix	Custom text before/after names (set via API by external plugins)
Health bars	Real-time health for each member
Energy bars	Real-time energy for each member
Mana bars	Real-time mana for each member

The HUD updates automatically every 250ms using GroupTracker, which caches health, energy, mana, position, level, and XP for each group member.

Technical Details

GroupManager includes InternalMultiHud, which serves a dual purpose:

• Standalone mode: If no external HUD plugin is installed, InternalMultiHud renders the group HUD natively. The HUD always works out of the box.
• MultipleHUD mode: When MultipleHUD is detected (highest priority), HUD calls are routed through MultipleHUD's API via reflection.
• AutoMultiHud fallback: When only AutoMultiHud is present, InternalMultiHud ensures all packets come from GroupManager's JAR, keeping a single AutoMultiHud group.

This means:

• No external HUD plugin is required — the group HUD works by default.
• When MultipleHUD is present, it takes priority and manages HUD groups natively.
• When only AutoMultiHud is present, InternalMultiHud handles compatibility automatically.
• No HUD plugin JAR is needed at build time — all detection is via reflection.

How resumeHud Works Internally

When resumeHud() is called (and no MultipleHUD/AutoMultiHud is handling HUDs), GroupManager performs a full state cleanup before recreating the HUD:

1. Removes the cached InternalMultiHud from its internal map (forces a fresh instance).
2. If AutoMultiHud is present, clears the player's state (playersWithMasterUi and hudMap).
3. Creates a new InternalMultiHud and calls player.getHudManager().setCustomHud() — which sends a Set packet (not Update).

This guarantees that AutoMultiHud initializes Master0.ui from scratch, avoiding stale state from a previous HUD session.

info

This cleanup is handled entirely inside GroupManager. External plugins don't need to worry about it — just call resumeHud() and the HUD will be restored correctly.

CSS Customization

If you're customizing your server's UI, the group HUD element uses:

#GroupMultiHUD {
    /* Your custom styles here */
}

API Control

External plugins can control the HUD per-player:

GroupService api = GroupManagerProvider.get();

// Hide HUD during a match
api.pauseHud(playerUuid);

// Restore HUD after match
api.resumeHud(playerUuid);

These methods are always safe to call, regardless of whether AutoMultiHud is installed. GroupManager handles AutoMultiHud detection internally — see below.

MultipleHUD / AutoMultiHud Compatibility

How It Works Internally

GroupManager detects MultipleHUD and AutoMultiHud at startup. When either is present, pauseHud() and resumeHud() become automatic no-ops — they return immediately without doing anything.

This is because both mods allow multiple plugins to display HUDs simultaneously — MultipleHUD via its native API, and AutoMultiHud by creating a separate group per plugin JAR. There's no need to hide one to show the other.

Scenario	Without HUD mods	With MultipleHUD or AutoMultiHud
pauseHud() called	Hides GroupHud (engine has single HUD slot)	No-op — both HUDs coexist
resumeHud() called	Restores GroupHud from scratch	No-op — GroupHud was never hidden
Your plugin shows a HUD	Replaces GroupHud (single slot)	Both HUDs visible simultaneously

What This Means For Your Plugin

You don't need to detect MultipleHUD or AutoMultiHud yourself. Just call pauseHud/resumeHud unconditionally — GroupManager handles the rest:

public void onActivityStart(Player player) {
    // Always safe to call — no-op if MultipleHUD/AutoMultiHud is present
    groupApi.pauseHud(player.getUuid());

    // Show your activity HUD
    showMyHud(player);
}

public void onActivityEnd(Player player) {
    hideMyHud(player);

    // Always safe to call — no-op if MultipleHUD/AutoMultiHud is present
    groupApi.resumeHud(player.getUuid());
}

Querying AutoMultiHud Status (Optional)

If your plugin needs to know whether AutoMultiHud is present for its own logic (e.g., to decide how to lay out its own HUD panels), the API exposes:

boolean autoMultiHud = groupApi.isAutoMultiHudPresent();

This is purely informational — you do not need to check this before calling pauseHud/resumeHud.

Complete Example: Activity HUD Management

public class MyActivityHud {

    private final GroupService groupApi;

    /** Called when a player enters the activity */
    public void onActivityStart(Player player) {
        // Pause GroupHud (internally no-op if MultipleHUD/AutoMultiHud is present)
        groupApi.pauseHud(player.getUuid());

        // Show your activity HUD
        showMyHud(player);
    }

    /** Called when a player exits the activity */
    public void onActivityEnd(Player player) {
        hideMyHud(player);

        // Resume GroupHud (internally no-op if MultipleHUD/AutoMultiHud is present)
        groupApi.resumeHud(player.getUuid());
    }

    /** Called when a player reconnects to an active activity */
    public void onActivityReconnect(Player player) {
        groupApi.pauseHud(player.getUuid());
        showMyHud(player);
    }
}

Key Rule

Just call pauseHud/resumeHud whenever your plugin needs to hide/restore the GroupHud. GroupManager handles MultipleHUD/AutoMultiHud compatibility internally — no detection code needed in your plugin.