MyArraylist

package otherfiles.com;

/*
This ArrayList class contains two instance variables:
int element[], and count;
The following methods are part of the class:
 public void addFirst(int number);
 public void addLast(int number);
 public void insertItemAt(int number,int position);
 public void removeFirst();
 public void removeLast();
 public void removeItemAt(int position);
 public boolean isFound(int number);
 public int getPosition(int number);
 public String toString()

 Some methods are already completed. Complete the other methods
 and test each method to see if they are working correctly.

*/
public class MyArraylist {

    int[] element;// this is your single dimensional array
    protected int count; // count will be used for monitoring the exact number of elements in element
                            // array

    public MyArraylist(int size) {
        // preparing the number of elements the array can hold
        element = new int[size];
    }

    public MyArraylist() {
        // the array is set to hold 10 elements
        // if this constructor is called, the array can hold 10 elements
        this(10);
    }

    public int getFirstElement() {
        return (!isEmpty()) ? element[0] : -1;
    }

    public int getLastElement() {
        return (!isEmpty()) ? element[count - 1] : -1; // ternary operator
    }

    public void doubleTheArray() {
        int[] temp = new int[element.length * 2];
        for (int i = 0; i < element.length; i++)
            temp[i] = element[i];
        element = temp;
    }

    public boolean isEmpty() {
        return count == 0;
    }

    public boolean isFull() {
        return count == element.length;
    }
    /**
     * count must be less than the size of the array, otherwise, you will encounter
     * ArrayIndexOutOfBoundsException this will cause ArrayIndexOutBoundException if
     * array is full,but wont because of the if statement
     */
    public void addLast(int number) {
        if (isFull())
            doubleTheArray();
        element[count++] = number;
    }
    //arr = 9 1 11 12 4 3 4 5 6 7
    //output = 12 4 3 4 5 6 7 9 1 11
    private void shiftLeft(int location) {
        int j;
        int temp = element[0];
        for(int i=0; i<location; i++) {
            //int temp = element[0];
            for(j=0; j<element.length-1; j++) {
                element[j] = element[j+1];
            }
            element[j] = temp;
        }
    }

    private void shiftRight(int location,int number) {
        count++;
        for(int i=element.length-1; i>location; i--) {
            element[i] = element[i-1];
        }
        element[location] = number;
    }

    public void addFirst(int number) {
        if (isFull())
            doubleTheArray();
        if (!isEmpty()) {
            shiftRight(0,number);
        }
    }

    public void removeFirst() {
        int[] newElem = null;
        if (!isEmpty()) {
            newElem = new int[element.length-1];
            for (int i = 0; i < newElem.length; i++) {
                newElem[i] = element[i+1];
            }count--;
        }
        element = newElem;
    }

    public void removeLast() {
        int[] newElem = null;
        if (!isEmpty()) {
            newElem = new int[element.length-1];
            for (int i = 0; i < newElem.length; i++)
                newElem[i] = element[i];
            count--;
        }
        element = newElem;
    }

    public void insertItemAt(int number, int position) {
        count++;
        for(int i=element.length-1; i>position; i--) {
            element[i] = element[i-1];
        }
        element[position] = number;
    }

    public void removeItemAt(int position) {
        count--;
        for(int i=position; i<element.length-1; i++) {
            element[i] = element[i+1];
        }
    }

    public boolean isFound(int number) {
        boolean res = false;
        for(int i=0; i<element.length; i++) {
            if(element[i]==number) {
                return true;
            }
        }
        return res;
    }

    public String toString() {
        // we override toString so that the object of ArrayList will have a String
        // representation, which is to display the elements from the beginning to the
        // end
        StringBuffer sb = new StringBuffer();
        sb.append("[ ");
        for (int i = 0; i < count; i++)
            sb.append(element[i] + " ");
        sb.append("]");
        return sb.toString();
    }

    public int getPosition(int number) {
        int count=0;
        for(int i=0; i<element.length; i++) {
            if(element[i]==number) {
                break;
            }
            count++;
        }
        return count;
    }

    public void doubleTheValue() {
        for (int i = 0; i < count; i++)
            element[i] = element[i] * 2;
    }

    public static void main(String[] args) {
        MyArraylist list = new MyArraylist();
        //list.addLast(0);
        list.addLast(2);
        list.addLast(3);
        list.addLast(4);
        list.addLast(5);
        list.addLast(6);
        list.addLast(7);
        list.addLast(8);
        System.out.println("List contains:" + list);
        list.removeFirst();
        System.out.println("List contains:" + list);
        list.addFirst(7);
        list.addFirst(4);
        list.addFirst(12);
        list.addFirst(1);
        list.addFirst(9);
        list.addFirst(10);
        System.out.println("Add first element:" + list);
        list.insertItemAt(11, 3);
        System.out.println("InsertItem List contains: " + list);
        list.removeFirst();
        System.out.println("RemoveFirst List contains:" + list);
        list.removeLast();
        System.out.println("RemoveLast List contains: " + list);
        list.removeItemAt(5);
        System.out.println("removeItem List contains: " + list);
        list.shiftLeft(3);
        System.out.println("ShiftLeft List contains: " + list);
        System.out.println("Location of 12 is at index: " + list.getPosition(12));
        System.out.println("is 5 found? " + list.isFound(5));
        list.doubleTheValue();
        System.out.println("List contains: " + list);

    }
}