initial working version

plugins {

	id 'com.github.johnrengelman.shadow' version '2.0.4'

	id 'java'

}

repositories {

	mavenCentral()

	maven { url = 'https://hub.spigotmc.org/nexus/content/repositories/snapshots/' }

	maven { url = 'https://oss.sonatype.org/content/repositories/snapshots' }

}

dependencies {

	compileOnly 'org.spigotmc:spigot-api:1.12.2-R0.1-SNAPSHOT'

	compile 'info.faljse:SDNotify:1.1'

}

rootProject.name = 'SpigotSystemd'

package jetzt.nicht.minecraft.spigotSystemd;

import org.bukkit.event.EventHandler;

import org.bukkit.event.EventPriority;

import org.bukkit.event.Listener;

import org.bukkit.event.server.PluginEnableEvent;

import jetzt.nicht.minecraft.spigotSystemd.SpigotSystemdPlugin;

public class PluginListener implements Listener {

	SpigotSystemdPlugin mainPlugin;

	public PluginListener(SpigotSystemdPlugin mainPlugin) {

		this.mainPlugin = mainPlugin;

	}

	@EventHandler(priority = EventPriority.MONITOR)

	public void onPluginEnabled(PluginEnableEvent event) {

		System.out.println("Some plugin has been enabled!");

		this.mainPlugin.onPluginEnabled();

	}

}

package jetzt.nicht.minecraft.spigotSystemd;

import org.bukkit.event.HandlerList;

import org.bukkit.plugin.Plugin;

import org.bukkit.plugin.java.JavaPlugin;

import info.faljse.SDNotify.SDNotify;

import jetzt.nicht.minecraft.spigotSystemd.PluginListener;

import jetzt.nicht.minecraft.spigotSystemd.StartupListener;

public class SpigotSystemdPlugin extends JavaPlugin {

	PluginListener pluginListener;

	StartupListener startupListener;

	@Override

	public void onEnable() {

		// we have been loaded, so the server has just been started

		// XXX: Check some other state, to become reload-safe!

		// Check systemd if our service is started!

		// Register our listener that waits for the server to be ready.

		// We pass in a reference to ourselves so the listener can call back.

		this.startupListener = new StartupListener(this);

		System.out.println("Registering StartupListener...");

		getServer().getPluginManager()

			.registerEvents(this.startupListener, this);

	}

	@Override

	public void onDisable() {

	}

	public void onServerMostlyReady() {

		System.out.println("The server is now \"mostly ready\"!");

		// Unregister the StartupListener, as the server is now

		// deemed "mostly ready"

		System.out.println("Unregistering StartupListener...");

		HandlerList.unregisterAll(this.startupListener);

		// Register our listener that waits for plugins to be enabled. See above.

		this.pluginListener = new PluginListener(this);

		System.out.println("Registering PluginListener...");

		getServer().getPluginManager()

			.registerEvents(this.pluginListener, this);

		// Trigger one execution of onPluginEnabled, as all plugins might have

		// been enabled already. This is a bit ugly but technically correct,

		// because at least we ourselves have been enabled.

		this.onPluginEnabled();

	}

	public void onPluginEnabled() {

		if (this.checkPluginsEnabled()) {

			System.out.println("All plugins have been enabled!");

			System.out.println("Unregistering PluginListener...");

			HandlerList.unregisterAll(this.pluginListener);

			System.out.println("Signalling readyness to systemd...");

			SDNotify.sendNotify();

		} else {

			System.out.println("There are still plugins to be enabled, continuing...");

		}

	}

	public boolean checkPluginsEnabled() {

		System.out.println("Checking whether all plugins have been enabled...");

		Plugin[] loadedPlugins = getServer().getPluginManager().getPlugins();

		boolean allPluginsEnabled = true;

		for (Plugin plugin : loadedPlugins) {

			System.out.println(

					String.format("%s: %b", plugin, plugin.isEnabled())

					);

			if (plugin.isEnabled() == false) {

				allPluginsEnabled = false;

				break;

			}

		}

		return allPluginsEnabled;

	}

}

package jetzt.nicht.minecraft.spigotSystemd;

import org.bukkit.event.EventHandler;

import org.bukkit.event.EventPriority;

import org.bukkit.event.Listener;

import org.bukkit.event.world.WorldInitEvent;

import jetzt.nicht.minecraft.spigotSystemd.SpigotSystemdPlugin;

public class StartupListener implements Listener {

	SpigotSystemdPlugin mainPlugin;

	public StartupListener(SpigotSystemdPlugin mainPlugin) {

		this.mainPlugin = mainPlugin;

	}

	@EventHandler(priority = EventPriority.MONITOR)

	public void onWorldInitialized(WorldInitEvent event) {

		System.out.println("Some World has been initialized!");

		this.mainPlugin.onServerMostlyReady();

	}

}