Database — Overview

DzusillCore provides a fully async, HikariCP-pooled SQL layer supporting MySQL and PostgreSQL. It is entirely optional: when disabled via config, the plugin runs normally without a database.

Architecture

DatabaseManager (Service)
  └─ Database (interface)
       ├─ MySqlDatabase       ← AbstractSqlDatabase
       └─ PostgreSqlDatabase  ← AbstractSqlDatabase
            └─ HikariCP connection pool
                 └─ queryOne / queryList / update / batch / withConnection
                       └─ RowMapper<T>
                            └─ CompletableFuture<T>  (async, off main thread)

Repository<ID,T>
  └─ AbstractSqlRepository
       └─ Database (uses dialect-aware upsert)

DataStore<String,V>
  └─ SqlDataStore   (bridges DataStore interface to SQL table)

Threading model

Every Database method returns a CompletableFuture<T> that runs on an off-main-thread executor (provided by SchedulerService.asyncExecutor()). Never block the main thread waiting for a database call.

To resume on the main thread (for Bukkit API calls), chain with thenAcceptAsync:

db.queryOne("SELECT coins FROM players WHERE uuid = ?",
            rs -> rs.getLong("coins"),
            player.getUniqueId().toString())
  .thenAcceptAsync(
      opt -> opt.ifPresent(coins -> player.sendMessage(
              ColorUtils.parse("<gold>Coins: " + coins))),
      scheduler.mainThreadExecutor());   // back on main thread

The enabled toggle

The database is disabled by default. Enable it in database.yml:

enabled: true

Code that optionally uses the database should check isEnabled():

DatabaseManager db = services.get(DatabaseManager.class);
if (db.isEnabled()) {
    db.database().update("INSERT INTO log ...", ...).join();
}

Or use optional():

db.optional().ifPresent(database -> {
    database.queryList(...).thenAccept(...);
});

What is shaded

The following are bundled inside the JAR:

Library	Location in JAR
HikariCP	me.dzusill.core.lib.hikari (relocated)
MySQL Connector/J	com.mysql (not relocated — loaded by explicit driver class name)
PostgreSQL JDBC	org.postgresql (not relocated)

Relocation prevents conflicts when other plugins on the same server also shade HikariCP.