package list.dl.algo;

import list.dl.DLList;

/**
 * Counts the number of elements in the host as a whole.
 * @dependency list.dl.algo.LeftCount
 * @dependency list.dl.algo.RightCount uses
 */
public class ElementCount implements IDLAlgo
{
    final public static ElementCount Singleton = new ElementCount();
    private ElementCount()
    {
    }

    /**
     * @param hostList 
     * @param inputParam
     */
    public Object visit(DLList hostList, Object inputParam)
    {
	Integer nLeft =  (Integer) hostList.executeLeft (LeftCount.Singleton, null);
	Integer nRight = (Integer) hostList.executeRight (RightCount.Singleton, null);
	return new Integer (nLeft.intValue () + nRight.intValue ());
   }
}