Object Pooling Example for Unity

PoolingExample.cs

using UnityEngine;
using System.Collections;

using Dbg = System.Diagnostics.Debug;

public class PoolingExample : MonoBehaviour {
	
	PoolingExample next;
	PoolingExample prefab;
	
	bool IsPrefab { get { return prefab == null; } }
	
	// call this method on prefabs to duplicate a new instance.  Will fail
	// to assert if called on instances.
	public PoolingExample Alloc(Vector3 position, Quaternion rotation) {
		Dbg.Assert(IsPrefab);
		if (next) {
			var result = next;
			next = next.next;
			result.transform.position = position;
			result.transform.rotation = rotation;
			result.next = null;
			result.gameObject.SetActive(true);
			return result;
		} else {
			var result = Instantiate(this, position, rotation) as PoolingExample;
			result.prefab = this;
			return result;
		}
	}
	
	// Destroy() unused instances
	void Drain() {
		Dbg.Assert(IsPrefab);
		while(next) {
			var p = next;
			next = next.next;
			Destroy(p);
		}
		next = null;
	}
	
	// Call this method on instances to return them to the candidate pool
	void Release() {
		Dbg.Assert(!IsPrefab);  
		next = prefab.next;
		prefab.next = this;
		gameObject.SetActive(false);
	}
}