Add methods from a ShadowArray ADT and a BruteArrayADT

BruteArrayAdd.java

//int numItems  ==> int to hold the number of Items in each underlying array
//E[] items     ==> the data structure used in the BruteArray ADT

public void add(E item) {
	//if the array needs to be expanded
  	if (numItems >= items.length) {
  		
  		//create a new array that is twice as long
		E[] brute = (E[])(new Object[items.length * 2]);
		
		//copy over all existing elements
		for (int i = 0; i < items.length; i++) {
			brute[i] = items[i];
		}
		
		//add the new element
		brute[numItems] = item;
		
		//make the underlying array point at the new, larger array
		items = brute;
	}
	//if not expansion...
	else {
		//just add the new item 
		items[numItems] = item;
	}
		
	//either way, item is added; increase count
	numItems++;
		
}

ShadowArrayAdd.java

//int numItems   ==> int to hold the number of Items in each underlying array
//int carryIndex ==> Index to copy over pre-existing elements to new shadow array
//E[] k          ==> the data structure used in the ShadowArray ADT
//E[] s          ==> the shadow array data structure used in the ShadowArray ADT
public void add(E item) {
	
	//if expansion is needed...
  	if (numItems >= k.length) {
		//set the k array to the shadow array
		k = s;
		
		//create a new larger shadow array
		s = (E[])(new Object[2*k.length]);
		
		//reset the index to copy over pre-existing elements
		carryIndex = 0;
		
		//add the new item to both arrays
		k[numItems] = item;
		s[numItems] = item;
			
		//copy over the first pre-existing element to the 
		//new shadow array
		s[carryIndex] = k[carryIndex];
	}
	//if no expansion needed...
	else {
		//add the new item to both arrays
		k[numItems] = item;
		s[numItems] = item;
			
		//copy over pre-existing elements
		s[carryIndex] = k[carryIndex];
	}
		
	//increase both counts
	carryIndex++;
	numItems++;
}

Test.java

//Same method is used for testing the BruteArray;
//just replace every instance of ShadowArray with BruteArray
public static void main(String[] args) {
  
  
  ShadowArray<String> shadow = new ShadowArray<Sring>();
  
  long start = System.currentTimeMillis();
  
  for (int i = 0; i < 1000000; i++) {
    shadow.add("arg");
  }
  
  long diff = System.currentTimeMillis() - start;
  
  System.out.println("Insertion Difference: " + diff);
  
}