[CODE] KWArrayList.java

/*
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Prepared by: OL Academy
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*/


import java.util.ArrayList;
import java.util.Arrays;


public class KWArrayList <E>{
    //Data fields
    private static final int INITIAL_CAPACITY = 10; // The default initial capacity
    private E[] theData;  // The underlying data array
    private int size ; // The current size
    private int capacity ;  // The current capacity

    //default constructor
    public KWArrayList()
    {
        capacity = INITIAL_CAPACITY;
        size = 0;
        theData = (E[]) new Object[capacity];
    }

    //constructor with parameter
    public KWArrayList(int cap)
    {
        capacity = cap;
        size = 0;
        theData = (E[]) new Object[capacity];
    }

    public int size(){return size;}
    public int getsize(){return size;}

    private void reallocate()
    {
        capacity *= 2;
        theData= Arrays.copyOf(theData,capacity);
    }


    public boolean isEmpty()
    {

        return size==0;
    }

    public boolean add(E item)
    {
        if(size == capacity)
            reallocate();

        theData[size] = item;
        size++;
        return true;
    }

    public void add(int index, E item)
    {
        if (index<0 || index >size)
            throw new ArrayIndexOutOfBoundsException(index);

        if(size == capacity)
            reallocate();

        for(int i = size; i>index; i--) //shift elements to the right
            theData[i] = theData[i-1];

        theData[index] = item;
        size ++;
    }

    public E get(int index)
    {
        if(index<0 || index>size)
            throw new ArrayIndexOutOfBoundsException(index);
        return theData[index];
    }

    public E set(int index, E item)
    {
        if(index <0 || index >= size)
            throw new ArrayIndexOutOfBoundsException(index);

        E oldValue = theData[index];
        theData[index] = item;
        return oldValue;
    }

    public int indexOf(E item)
    {
        for(int i=0; i<size; i++)
            if(theData[i].equals(item))
                return i;
        return -1;
    }

    public boolean contains(E item)
    {
        for(int i=0; i<size; i++)
            if(theData[i].equals(item))
                return true;

        return false;
    }



    public E remove(int index)
    {
        if(index <0 || index >= size)
            throw new ArrayIndexOutOfBoundsException(index);

        E deleted = theData[index];

            for(int i=index+1; i<size; i++)
                theData[i-1]= theData[i];
            size--;
            return deleted;
    }

    public boolean remove(E item) {
        int index = indexOf(item);
        if (index != -1) {
            remove(index);
            return true;

        } else return false;
    }

    public void clear()
    {
        for(int i=0; i<size; i++)
            theData[i] = null;
        size = 0;
    }

    public String toString()
    {
        String str ="[";
        for (int i=0; i<size; i++){
            if (i==size-1)
                str += theData[i];
            else
                str += theData[i]+ ", ";
        }
        return str + "]";
    }
}