26.2 Architecture and Mixins

🧩 Architecture & Mixin Subsystem

Parameter	Specification
Mixin Configuration	src/main/resources/collapsible-game-rules.mixins.json
Refmap Identifier	collapsible-game-rules-refmap.json
Compatibility Level	JAVA_25
Default Require	1
Root Package	net.instantgratification.collapsiblegamerules
Mixin Package	net.instantgratification.collapsiblegamerules.mixin
Total Mixins	4 Client Mixins (3 Class Injectors + 1 Interface Accessor)

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📖 System Package Architecture

net.instantgratification.collapsiblegamerules
├── CollapsibleGameRulesFabric.java           ──> Main ModInitializer (Guard & Hard Dependency check)
├── CollapsibleGameRulesFabricClient.java     ──> ClientModInitializer (Loads GameRuleStateConfig)
├── GameRuleStateConfig.java                  ──> Config & JSON state persistence (Set<String>)
├── mixin
│   ├── AbstractGameRulesScreenRuleListMixin.java ──> Core engine (List interception, CollapsibleCategoryRuleEntry)
│   ├── CategoryRuleEntryAccessor.java        ──> Interface Accessor for category Component label
│   ├── IntegerRuleEntryMixin.java            ──> Abstract wrapper for integer rule entries
│   └── ScreenMixin.java                      ──> Intercepts Screen.removed() to flush pending state
├── preset
│   └── GameRulePresetEngine.java             ──> Built-in preset definitions (Builder, Fast Play, Hardcore)
├── ui
│   ├── BooleanToggleWidget.java              ──> Interactive emerald green / ruby red toggle switch
│   ├── GlobalActionsRuleEntry.java           ──> Pinned index 0 bulk toggle header ([ Expand ] / [ Collapse ])
│   └── IntegerSliderWidget.java              ──> Draggable numeric slider with math normalization
└── util
    ├── CategoryPrettifier.java               ──> Regex & string parser for unlocalized category keys
    ├── DasikMetadataHelper.java              ──> Lazy-loaded isolation layer querying DasikLibrary
    ├── GameRuleSliderHelper.java             ──> Vanilla integer rule bounds and default values
    └── ModVersionGuard.java                  ──> Zero-dependency runtime Knot ClassLoader integrity check

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🔍 Complete Mixin Target Breakdown

1. AbstractGameRulesScreenRuleListMixin

• Target Class: net.minecraft.client.gui.screens.worldselection.AbstractGameRulesScreen.RuleList.class
• Hierarchy: Extends ContainerObjectSelectionList<AbstractGameRulesScreen.RuleEntry>
• Role: Primary UI controller. Intercepts list population, calculates child count per category, filters visible entries based on expansion states, and renders custom interactive category headers.

@Mixin(AbstractGameRulesScreen.RuleList.class)
public abstract class AbstractGameRulesScreenRuleListMixin
        extends ContainerObjectSelectionList<AbstractGameRulesScreen.RuleEntry> {

    @Unique
    private List<AbstractGameRulesScreen.RuleEntry> collapsible_game_rules$allEntries = new ArrayList<>();

    @Unique
    private String collapsible_game_rules$currentFilter = "";

    @Inject(method = "populateChildren(Ljava/lang/String;)V", at = @At("TAIL"))
    private void collapsible_game_rules$onPopulateChildren(String filter, CallbackInfo ci) {
        this.collapsible_game_rules$currentFilter = (filter != null) ? filter.toLowerCase(java.util.Locale.ROOT) : "";
        this.collapsible_game_rules$allEntries = new ArrayList<>(this.children());
        this.collapsible_game_rules$updateVisibleEntries();
    }
}

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2. CategoryRuleEntryAccessor

• Target Class: net.minecraft.client.gui.screens.worldselection.AbstractGameRulesScreen.CategoryRuleEntry.class
• Role: Provides direct bytecode accessor to the private Component label field of vanilla category entries.

@Mixin(AbstractGameRulesScreen.CategoryRuleEntry.class)
public interface CategoryRuleEntryAccessor {
    @Accessor("label")
    Component collapsible_game_rules$getLabel();
}

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3. ScreenMixin

• Target Class: net.minecraft.client.gui.screens.Screen.class
• Role: Listens for screen removal. Whenever AbstractGameRulesScreen is closed, flushes pending state modifications to disk via GameRuleStateConfig.saveIfDirty().

@Mixin(Screen.class)
public abstract class ScreenMixin {

    @Inject(method = "removed", at = @At("HEAD"))
    private void collapsible_game_rules$onRemoved(CallbackInfo ci) {
        if ((Object) this instanceof AbstractGameRulesScreen) {
            GameRuleStateConfig.saveIfDirty();
        }
    }
}

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4. IntegerRuleEntryMixin

• Target Class: net.minecraft.client.gui.screens.worldselection.AbstractGameRulesScreen.IntegerRuleEntry.class
• Role: Provides an abstract bridge into vanilla integer rule entries for specialized widget integration.

@Mixin(AbstractGameRulesScreen.IntegerRuleEntry.class)
public abstract class IntegerRuleEntryMixin extends AbstractGameRulesScreen.RuleEntry {
    public IntegerRuleEntryMixin() {
        super(null);
    }
}

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📜 Mixin Configuration File (collapsible-game-rules.mixins.json)

{
    "required": true,
    "package": "net.instantgratification.collapsiblegamerules.mixin",
    "refmap": "collapsible-game-rules-refmap.json",
    "compatibilityLevel": "JAVA_25",
    "client": [
        "ScreenMixin",
        "AbstractGameRulesScreenRuleListMixin",
        "CategoryRuleEntryAccessor",
        "IntegerRuleEntryMixin"
    ],
    "injectors": {
        "defaultRequire": 1
    }
}

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🔗 Related Documentation

• Master Wiki Portal
• MC 26.2 Version Portal
• Collapsible Categories
• State Persistence & JSON Config
• DasikLibrary API Integration