TagCore

TagCore is a Hytale server mod/plugin that adds a simple, reusable tag system for game content.

It lets you define named groups of IDs such as items, blocks, entities, biomes, effects, fluids, and damage types, then query those groups through a clean Java API.

Features

• Define tags in JSON
• Support for these tag types:
  • item
  • block
  • entity
  • biome
  • effect
  • fluid
  • damage_type
• Reference one tag from another with #namespace:path
• Resolve fully flattened tag contents at startup
• Detect invalid values, missing references, wrong-type references, and circular references
• Load tags from:
  • bundled classpath resources under tags/
  • external .zip and .jar packs from the server mods/ directory
• Easy-to-use TagService API for other mods/plugins

How Tag IDs Work

Tag IDs use a namespace:path format.

Examples:

• hytale:logs
• tagcore:starter_weapons
• mymod:undead

If a tag ID is written without a namespace, TagCore normalizes it to the default namespace:

hytale

So a bare tag like:

starter_weapons

is treated as:

hytale:starter_weapons

Defining Tags

Tag files are JSON files placed under a tags/ directory.

A tag definition contains:

• id - the tag ID
• type - the tag type
• values - a list of concrete IDs and/or tag references

Example item tag

{
  "id": "tagcore:starter_weapons",
  "type": "item",
  "values": [
    "Weapon_Sword_Wood",
    "Weapon_Shortbow_Crude",
    "#tagcore:starter_ammo"
  ]
}

Example block tag

{
  "id": "tagcore:logs",
  "type": "block",
  "values": [
    "Wood_Amber_Trunk",
    "Wood_Ash_Trunk",
    "Wood_Aspen_Trunk"
  ]
}

Example entity tag

{
  "id": "tagcore:undead",
  "type": "entity",
  "values": [
    "Zombie",
    "Skeleton",
    "#tagcore:boss_undead"
  ]
}

Referencing Other Tags

You can include one tag inside another by prefixing the referenced tag ID with #.

{
  "id": "tagcore:all_logs",
  "type": "block",
  "values": [
    "#tagcore:logs",
    "#tagcore:modded_logs"
  ]
}

Rules:

• referenced tags must exist
• referenced tags must be the same type
• circular references are rejected

Where Tags Are Loaded From

TagCore loads tags from two places, in this order:

1. Classpath resources under tags/
2. External .zip or .jar packs in the server mods/ directory

External packs can override built-in tags with the same ID.

Using the API

TagCore exposes a shared TagService for querying tags.

Get the shared service

import com.azuredoom.tagcore.api.TagService;

var tagServiceOptional = TagService.getTagService();
if (tagServiceOptional.isEmpty()) {
    return;
}

TagService tagService = tagServiceOptional.get();

Check whether a tag exists

boolean exists = tagService.hasTag("tagcore:starter_weapons");

Resolve a typed tag

var result = tagService.resolveItemTag("tagcore:starter_weapons");

if (result.isSuccess()) {
    for (String itemId : result.value()) {
        System.out.println(itemId);
    }
} else {
    System.out.println("Failed to resolve tag: " + result.status());
    for (var issue : result.issues()) {
        System.out.println(issue.detail());
    }
}

Check membership in a tag

var result = tagService.isInItemTag("tagcore:starter_weapons", "Sword_Wooden");

if (result.isSuccess() && result.value()) {
    System.out.println("Sword_Wooden is in the tag.");
}

Resolve a block tag

var logs = tagService.resolveBlockTag("tagcore:logs");

if (logs.isSuccess()) {
    System.out.println("Resolved block IDs: " + logs.value());
}

Generic membership check

var result = tagService.isInTag("tagcore:starter_weapons", "Sword_Wooden");

if (result.isSuccess()) {
    System.out.println("Contained: " + result.value());
}

Understanding Query Results

Most TagCore API calls return a TagQueryResult<T>.

This gives you:

• status() - overall outcome
• value() - returned value
• definition() - matching tag definition, when available
• issues() - validation or resolution issues

Common statuses:

• SUCCESS
• EMPTY
• NOT_FOUND
• WRONG_TYPE
• INVALID_TAG_ID
• INVALID_CONTENT
• CIRCULAR_REFERENCE

Example:

var result = tagService.resolveBlockTag("tagcore:logs");

switch (result.status()) {
    case SUCCESS, EMPTY -> {
        System.out.println("Resolved values: " + result.value());
    }
    case NOT_FOUND -> {
        System.out.println("Tag not found.");
    }
    default -> {
        System.out.println("Tag resolution failed: " + result.status());
        for (var issue : result.issues()) {
            System.out.println(issue.type() + ": " + issue.detail());
        }
    }
}

Recommended Folder Layout

Example bundled resource layout:

src/main/resources/
└── tags/
    ├── items/
    │   └── starter_weapons.json
    ├── blocks/
    │   └── logs.json
    └── entities/
        └── undead.json

The exact subfolder structure under tags/ is flexible. What matters is that the files are discoverable under the tags/ root.

Example Pack Override

You can ship a default tag in your mod, then override it from an external pack in mods/.

Bundled tag:

{
  "id": "tagcore:starter_weapons",
  "type": "item",
  "values": [
    "Sword_Wooden"
  ]
}

External override:

{
  "id": "tagcore:starter_weapons",
  "type": "item",
  "values": [
    "Sword_Wooden",
    "Bow_Basic",
    "Dagger_Rusty"
  ]
}

Notes

• Values must be valid IDs for the declared type.
• References must point to tags of the same type.
• TagCore resolves references eagerly so configuration problems show up early.
• Bare tag IDs are normalized to the default namespace hytale.

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