[BukkitPlugin]左クリックで矢を跳ね返すプラグイン。

ArrowReturn.java

package org.densyakun.arrowreturn;

import java.util.ArrayList;
import java.util.List;

import org.bukkit.Material;
import org.bukkit.entity.EntityType;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.block.Action;
import org.bukkit.event.entity.EntityDamageByEntityEvent;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.plugin.java.JavaPlugin;

import net.minecraft.server.v1_8_R3.EntityArrow;

public class ArrowReturn extends JavaPlugin implements Listener {

	static List<Player> a = new ArrayList<Player>();

	@Override
	public void onEnable() {
		getServer().getPluginManager().registerEvents(this, this);
	}

	@EventHandler
	public void a(PlayerInteractEvent a) {
		if ((a.getAction() == Action.LEFT_CLICK_AIR || a.getAction() == Action.LEFT_CLICK_BLOCK)
				&& a.getPlayer().getItemInHand() != null
				&& a.getPlayer().getItemInHand().getType() == Material.GOLD_SWORD)
			new a(a.getPlayer());
	}

	@EventHandler
	public void ArrowAttack(EntityDamageByEntityEvent evt) {
		if (evt.getDamager().getType() == EntityType.ARROW && evt.getEntityType() == EntityType.PLAYER
				&& c((Player) evt.getEntity())
				&& ((Player) evt.getEntity()).getItemInHand().getType() == Material.GOLD_SWORD) {
			evt.setCancelled(true);
			EntityArrow arrow = (EntityArrow) evt.getEntity();
			
			float yaw;
			float pitch;
			
			if ((arrow.yaw + 180) >= 360)
				yaw = arrow.yaw + 180;
			else
				yaw = arrow.yaw - 180;
			
			if ((arrow.pitch + 180) >= 360)
				pitch = arrow.pitch + 180;
			else
				pitch = arrow.pitch - 180;
			
			arrow.shoot(arrow.lastX, arrow.lastY, arrow.lastZ, yaw, pitch);
		}
	}

	public boolean c(Player b) {
		for (int c = 0; c < a.size(); c++)
			if (b.getName().equals(a.get(c).b) && c)
				return true;
		return false;
	}

	private static class a implements Runnable {
		boolean c = true;
		public a(Player b) {
			Start.a.add(b);
			new Thread(this).start();
		}

		@Override
		public void run() {
			try {
				Thread.sleep(125);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			c = false;
		}
	}
}