RestrictMob

A lightweight, high-performance Minecraft plugin that allows server administrators to define Safe Zones where hostile and neutral mobs cannot spawn or enter.

Built for Paper 1.21+ with Java 21. Zero per-tick overhead — uses event-driven checks only.

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Features

• Zone Creation — Select two corners with a wand item (default: Blaze Rod) and define named rectangular zones.
• Spawn Prevention — Blocks hostile and neutral mob spawns inside zones from all sources (natural, spawner, egg, custom, etc.).
• Entry Prevention — Prevents mobs from walking or teleporting into zones using Paper's EntityMoveEvent with proximity pre-filtering.
• Knockback — Mobs attempting to cross a zone boundary are gently pushed back (configurable strength).
• Async Persistence — Zones are saved to data/zones.yml asynchronously. No file I/O on the main thread during gameplay.
• Fully Configurable — Wand item, check radius, knockback multiplier, teleport blocking toggle, and all messages are editable in config.yml.

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Requirements

Requirement	Version
Server	Paper 1.21+ (or any Paper fork such as Purpur)
Java	21 or newer
Build Tool	Maven 3.9+

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Installation

1. Clone the repository and build:

   mvn clean package
   

2. Copy target/RestrictMob-1.0.jar into your server's plugins/ folder.
3. Restart or reload the server.

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Commands

All commands require the titanzones.admin permission (default: op).

Command	Description
/zones wand	Gives the selection wand item
/zones create <name>	Creates a zone from your current two-point selection
/zones delete <name>	Removes a saved zone
/zones list	Lists all active zones with coordinates

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Selection Workflow

1. Run /zones wand to receive the selection tool.
2. Left-click a block to set Position 1.
3. Right-click a block to set Position 2.
4. Run /zones create <name> to save the zone.

Both positions must be in the same world. The wand is identified by a persistent data tag, not by its display name.

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Configuration

Default config.yml:

wand-item: BLAZE_ROD
check-radius: 5.0
knockback-multiplier: 1.5
block-teleport: true

messages:
  prefix: "&8[&6TitanZones&8] "
  zone-created: "&aZone '&e%name%&a' created successfully."
  zone-deleted: "&cZone '&e%name%&c' deleted."
  # ... (all messages are customizable)

Key	Description
wand-item	Material name for the selection wand
check-radius	Distance (blocks) from zone boundaries to begin evaluating entity movement
knockback-multiplier	Velocity multiplier for boundary knockback. Set to 0 to disable.
block-teleport	Whether to cancel entity teleportation into zones

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How It Works

• Spawn blocking listens to CreatureSpawnEvent and EntitySpawnEvent. Any hostile or neutral mob spawning inside a zone is cancelled regardless of spawn reason.
• Movement blocking uses Paper's EntityMoveEvent with a three-stage filter:
  1. Skip non-restricted entities (players, passive animals, villagers).
  2. Skip sub-block movement (hasChangedBlock() check).
  3. Skip entities far from any zone (pre-expanded bounding box proximity test).
  4. Cancel and apply knockback only when a mob crosses from outside to inside a zone.
• Teleport blocking intercepts EntityTeleportEvent for the same entity types.
• Entities already inside a zone (e.g., zone created around them) are allowed to move freely so they can leave.

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Permissions

Permission	Description	Default
titanzones.admin	Access to all /zones commands	op

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Project Structure

src/main/java/com/titanzones/
  TitanZonesMain.java      Plugin entry point
  ZoneManager.java          Zone storage, spatial queries, async I/O
  ZoneCommand.java          Command handler and selection tracking
  ZoneTabCompleter.java     Tab completion for subcommands and zone names
  ZoneListener.java         Event listeners for spawns, movement, teleport, wand clicks

src/main/resources/
  plugin.yml                Plugin metadata
  config.yml                Default configuration

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License

This project is provided as-is. See the repository for license details.