using UnityEngine;

/// <summary>
/// Simple implementation of a singleton instance for any script.
/// </summary>
public class Singleton<T> where T : MonoBehaviour
{
	/// <summary>
	/// Write-once, read-many object reference.  Set this value at least 
	/// once and all objects will have access to it as a singleton.
	/// </summary>
	public static T instance
	{
		get { return _instance; }
		set { if (_instance == null) _instance = value; }
	}

	/// <summary>
	/// Returns true iff a singleton has been assigned for this class.
	/// </summary>
	public static bool assigned
	{
		get { return instance != null; }
	}

	/// <summary>
	/// current object reference
	/// </summary>
	private static T _instance = null;
}

/// <summary>
/// Avoids unity compiler warning in Unity 2.5 and earlier.
/// </summary>
public class Singleton {}