MMG articles: 2012

Aug 30, 2012

SimpleCache in HaXe

Made SimpleCache class based on Ant.Karlov tutorial using HaXe.
Here is class code:

package mmg;

class SimpleCache<t>
{
    public var instance(get, never):T;

    private var _targetClass:Class<t>;
    private var _currentIndex:Int;
    private var _instances:Array<t>;

    public function new(targetClass:Class<t>, initialCapacity:Int)
    {
        _targetClass = targetClass; // Base class of all of objects
        _currentIndex = initialCapacity - 1; // Index of current free object
        _instances = []; // Array of all instances

        // Fill it up
        for (i in 0...initialCapacity)
        {
            _instances[i] = getNewInstance();
        }
    }

    private function getNewInstance():T
    {
        return Type.createEmptyInstance(_targetClass);
    }

    private function get():T
    {
        if (_currentIndex >= 0)
        {
            // Returning free object from cache
            _currentIndex--;
            return _instances[_currentIndex + 1];
        }
        else
        {
            // If cache is empty we should create one more instance
            return getNewInstance();
        }
    }

    private function put(instance:T):Void
    {
        _currentIndex++;
        // If cache is overfilled
        if (_currentIndex == _instances.length)
        {
            // We should put instance to the back of the instances array
            _instances[_instances.length] = instance;
        }
        else
        {
            // Putting instance to the free cell of array
            _instances[_currentIndex] = instance;
        }
    }
}

Usage example:

// init cache
var cache:SimpleCache<ourobjectclass> = new SimpleCache(OurObjectClass, 50); 
// take on of instances
var tmp:OurObjectClass = cache.instance; 
tmp.doSomething();
// put object back to cache
cache.put(tmp);