class Slot {
  . . .
  /// 

  /// Constructs a Slot object for a pre-existing pooled type object.
  /// 
  public Slot(T poolObject) {
    if (poolObject == null)
      throw new ArgumentNullException("poolObject");
    this.poolObject = poolObject;
  }
  . . .
}
	
class Pool {
  . . .
  private Pool( ) {
    pool = new List<Slot>( );
  }
	
  /// 

  /// Constructs a pool and fills its list of pooled objects with the objects
  /// passed in to this constructor.
  /// 
  public Pool(IEnumerable<T> objects) : this( ) {
    foreach (T entry in objects)
      pool.Add(new Slot(entry));
  }
  . . .
}

class Pool {
  . . .
  object poolLock = new object( );
	
  /// 

  /// Returns a pooled object. After use, the pooled object must be returned to the
  /// pool by calling the ReleaseObject method.
  /// 
  public T GetObject( ) {
    lock (poolLock) {
      Slot unusedSlot = pool.Find(delegate(Slot slot) {
        return !slot.InUse;
      });
      if (unusedSlot != null) {
        unusedSlot.Occupy( );
        return unusedSlot.PoolObject;
      }
    }
    throw new OutOfObjectsException( );
  }
	
  /// 

  /// Releases an object that was previously fetched from the pool
  /// by a call to the GetObject method.
  /// 
  public void ReleaseObject(T poolObject) {
    lock (poolLock) {
      Slot objectSlot = pool.Find(delegate(Slot slot) {
        return EqualityComparer<T>.Default.Equals(slot.Object, poolObject);
      });
      if (objectSlot != null)
        objectSlot.Release( );
      else
        throw new ArgumentException("The given object is not part of this pool.");
    }
  }
  . . .
}
	
class Slot {
  . . .
  /// 

  /// Marks the slot as being in use.
  /// 
  public void Occupy( ) {
    inUse = true;
  }
	
  /// 

  /// Marks the slot as being available.
  /// 
  public void Release( ) {
    inUse = false;
  }
  . . .
}
	
[Serializable]
public class OutOfObjectsException : Exception {
  public OutOfObjectsException( ) { }
  public OutOfObjectsException(string message) : base(message) { }
  public OutOfObjectsException(string message, Exception innerException) : base(message, innerException) { }
  protected OutOfObjectsException(SerializationInfo info, StreamingContext context) : base(info, context) { }
}