Scheduler

EriScheduler — Static API

EriScheduler is the main entry point. All methods are static, so you never need to instantiate anything. Every scheduling call returns a ScheduledTask that you can use to pause, resume, or cancel the task later.

Delayed execution

Run a block of code once after a given number of ticks:

// Execute once after 20 ticks (1 second)
ScheduledTask task = EriScheduler.delay(20, () -> {
    player.sendMessage(new TextComponentString("1 second later!"));
});

Fixed-count repetition

Run a block every N ticks for a maximum number of executions:

// Run every 20 ticks, up to 5 times
ScheduledTask task = EriScheduler.repeat(20, 5, () -> {
    System.out.println("Tick!");
});

Infinite repetition

Run a block every N ticks indefinitely until cancelled:

// Run every 100 ticks (5 seconds) forever
ScheduledTask task = EriScheduler.repeat(100, () -> {
    System.out.println("Every 5 seconds");
});

Cancel all tasks

// Stop every running task immediately
EriScheduler.cancelAll();

Method reference

ScheduledTask — Task reference

Every call to EriScheduler.delay() or EriScheduler.repeat() returns a ScheduledTask object. Hold onto this reference if you need to control the task after scheduling it.

ScheduledTask task = EriScheduler.repeat(20, () -> doStuff());

// Pause without losing the execution count
task.pause();

// Resume from where it was paused
task.resume();

// Stop permanently
task.cancel();

// Query the task's current state
boolean running   = task.isRunning();
boolean cancelled = task.isCancelled();
boolean paused    = task.isPaused();

// How many times has the runnable been executed so far?
int count = task.getExecutionCount();

Method reference

TaskChain — Sequential chain

A TaskChain lets you queue a series of tasks where each one fires after a specified delay following the previous step. Call EriScheduler.chain() to create one, add steps with .then(delay, runnable), and start the sequence with .run().

This is ideal for cutscene-style sequences, tutorial steps, timed announcements, or any workflow where things need to happen in a strict order with controlled pauses between them.

EriScheduler.chain()
    .then(0,  () -> System.out.println("Now"))
    .then(20, () -> System.out.println("1s later"))
    .then(40, () -> System.out.println("2s later"))
    .run();

Method reference

AsyncExecutor — Async tasks

EriScheduler.async() runs a Callable on a background thread, keeping the main game thread responsive. The returned AsyncExecutor handle lets you attach callbacks that run back on the main thread once the async work is done, or handle errors gracefully.

Use this for anything that might block — HTTP requests, file I/O, heavy computation — to avoid causing lag spikes in the game.

EriScheduler.async(() -> {
    // Runs off the main thread
    return fetchDataFromWeb();
}).onError(e -> {
    System.err.println("Error: " + e.getMessage());
}).thenSync(result -> {
    // Runs back on the main thread once the async work completes
    player.sendMessage(new TextComponentString("Data: " + result));
});

Method reference

Complete example — Countdown

This example shows a practical countdown timer that sends messages to the player every second, then announces "Go!" when it reaches zero. It combines repeat with a fixed execution count and an inline state variable.

final int[] count = {5};

ScheduledTask countdown = EriScheduler.repeat(20, 6, () -> {
    if (count[0] > 0) {
        player.sendMessage(new TextComponentString(count[0] + "..."));
        count[0]--;
    } else {
        player.sendMessage(new TextComponentString("Go!"));
    }
});

The task runs 6 times total (once per second for 5 seconds, then the "Go!" message on the 6th tick). After 6 executions the scheduler automatically stops it. The final int[] trick is necessary because Java 8 lambdas can only capture effectively final variables — wrapping the counter in a single-element array works around this limitation.

Countdown with a chain variant

You can also express the same countdown as a TaskChain for explicit control over each step:

EriScheduler.chain()
    .then(0,   () -> player.sendMessage(new TextComponentString("5...")))
    .then(20,  () -> player.sendMessage(new TextComponentString("4...")))
    .then(20,  () -> player.sendMessage(new TextComponentString("3...")))
    .then(20,  () -> player.sendMessage(new TextComponentString("2...")))
    .then(20,  () -> player.sendMessage(new TextComponentString("1...")))
    .then(20,  () -> player.sendMessage(new TextComponentString("Go!")))
    .run();