A queue for object recycling, similar to UITableView/UICollectionView recycling.

recycleQueue.swift

class ObjectQueue<T : NSObject> {
    
    private var used : [T] = []
    private var free : [T] = []
    
    /** Recycle or create object. */
    func dequeueObject () -> T {
        
        var object : T
        
        if let first = self.free.first {
            object = first
            
            free.removeAtIndex(0)
        }
        else
        {
            object = T()
        }
        
        used.append(object)
        
        return object
    }
    
    /** Add an object to the queue for later. */
    func enqueueObject(object : T) {
        
        self.free.append(object)

        if let index = self.used.indexOf(object) {
            self.used.removeAtIndex(index)
        }
    }
    
}