LivingEntityMapAdapter.java

package tc.oc.commons.bukkit.util;

import org.bukkit.entity.Entity;
import org.bukkit.entity.LivingEntity;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.EntityDeathEvent;
import org.bukkit.event.world.WorldUnloadEvent;
import org.bukkit.plugin.Plugin;

import java.util.Map;
import java.util.WeakHashMap;

/**
 * Uses {@link ListeningMapAdapter} to guarantee that the map only contains alive entity.
 */
public class LivingEntityMapAdapter<V> extends ListeningMapAdapter<LivingEntity, V> implements Listener {

    public LivingEntityMapAdapter(Plugin plugin) {
        super(new WeakHashMap<LivingEntity, V>(), plugin);
    }

    @Override
    public boolean isValid(LivingEntity key) {
        return key != null && !key.isDead();
    }

    @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
    public void onEntityDeath(EntityDeathEvent event) {
        this.remove(event.getEntity());
    }

    @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
    public void onWorldUnload(WorldUnloadEvent event) {
        for(Entity entity : event.getWorld().getEntities()) {
            map.remove(entity);
        }
    }

    protected Map<LivingEntity, V> delegate() {
        return this.map;
    }
}