Java Programming,

I only need help with implementing ensureCapacity method at the bottom of the code, and a 2nd invariant checker to _wellFormed. More direction is within the code, thanks.

package lab3;

public class IntArrayBag implements Cloneable { private Integer[] data; private int manyItems;

public IntArrayBag() { final int INITIAL_CAPACITY = 10; manyItems = 0; data = new Integer[INITIAL_CAPACITY]; }

public IntArrayBag(int initialCapacity) { if (initialCapacity < 0) { throw new IllegalArgumentException("initialCapacity is negative: " + initialCapacity); } manyItems = 0; data = new Integer[initialCapacity]; }

public void add(Integer element) { if (element == null) throw new IllegalArgumentException(); assert wellFormed() : "Failed at the start of add"; ensureCapacity(manyItems + 1); data[manyItems] = manyItems + 1; manyItems++; assert wellFormed() : "Failed at the end of add"; }

private boolean _report(String message) { System.out.println(message); return false; }

private boolean wellFormed() { // Make assertions about the invariant, returning false

// #1. manyItems should never be greater than data.length if (manyItems > data.length) return _report("manyItems is greater than data.length");

// #2. When the bag isn't empty, then items data[0] to data[manyItems-1] // should contain data and therefore not be null // (this is because null data are not allowed in this bag) // TODO Implement the 2nd Invariant

// All invariant assertions passed so return true return true; }

public boolean remove(Integer target) { if (target == null) throw new IllegalArgumentException(); assert wellFormed() : "Failed at the start of remove";

int index = 0; while ((index < manyItems) && (target != data[index])) { index++; }

if (index == manyItems) { return false; } else { data[index] = null; --manyItems; assert wellFormed() : "Failed at the end of remove"; return true; } }

public int size() { return manyItems; }

public int getCapacity() { return data.length; }

public int countOccurrences(Integer target) { if (target == null) throw new IllegalArgumentException(); assert wellFormed() : "Failed at the start of countOccurrences"; int answer = 0; int index = 0;

for (index = 0; index < manyItems; index++) { if (target == data[index]) { answer++; } } return answer; }

public void ensureCapacity(int minimumCapacity) { // TODO implement this method // Do nothing if the current capacity is at least minimumCapacity // Otherwise make a bigger array of the larger of // minimumCapacity and one more than twice the current capacity then copy elements over } }