working on myarraylist

src/main/java/MyArrayList.java

@@ -1,2 +1,127 @@
-public class MyArrayList {
+import java.lang.reflect.Array;
+
+public class MyArrayList<T> {
+
+    private T[] originalArray;
+    private int size;
+
+    public MyArrayList() {
+        this.size = 0;
+        this.originalArray = (T[]) new Object[0];
+    }
+
+    public MyArrayList(int size) {
+        this.size = size;
+        this.originalArray = (T[]) new Object[size];
+    }
+
+
+    public void add(T value) {
+        T[] newArray = (T[]) Array.newInstance(this.originalArray.getClass().getComponentType(), originalArray.length + 1);
+        // T[] newArray = (T[]) new Object[originalArray.length + 1];
+
+        for (int i = 0; i < originalArray.length; i++) {
+            newArray[i] = originalArray[i];
+        }
+
+        newArray[newArray.length - 1] = value;
+        setOriginalArray(newArray);
+        setSize(newArray.length);
+    }
+
+    public void add(T value, int index) {
+        T[] newArray = (T[]) Array.newInstance(this.originalArray.getClass().getComponentType(), originalArray.length + 1);
+
+        for (int i = 0; i < newArray.length; i++) {
+            if (i < index) {
+                newArray[i] = originalArray[i];
+            } else if (i == index) {
+                newArray[i] = value;
+            } else if (i > index) {
+                newArray[i] = originalArray[i - 1];
+            }
+        }
+
+        setOriginalArray(newArray);
+        setSize(newArray.length);
+    }
+
+    public T get(int index) {
+        return originalArray[index];
+    }
+
+    public void remove(T value) {
+        T[] newArray = (T[]) Array.newInstance(this.originalArray.getClass().getComponentType(), originalArray.length - 1);
+        int indexToRemove = 0;
+
+        for (int i = 0; i < originalArray.length; i++) {
+            if (originalArray[i] == value) {
+                indexToRemove = i;
+            }
+        }
+
+        for (int i = 0; i < originalArray.length; i++) {
+            if (i < indexToRemove) {
+                newArray[i] = originalArray[i];
+            } else if (i > indexToRemove) {
+                newArray[i - 1] = originalArray[i];
+            }
+        }
+
+        setOriginalArray(newArray);
+        setSize(newArray.length);
+    }
+
+    public void set(int index, T value) {
+        originalArray[index] = value;
+    }
+
+    public void clear() {
+        setOriginalArray((T[]) Array.newInstance(this.originalArray.getClass().getComponentType(), 0));
+        setSize(0);
+    }
+
+    public boolean isEmpty() {
+        if (this.size() == 0) {
+            return true;
+        }
+        return false;
+    }
+
+    public boolean contains(T value) {
+        for (int i = 0; i < originalArray.length; i++) {
+            if (originalArray[i] == value) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public int indexOf(T value) {
+        return 0;
+    }
+
+    public int lastIndexOf(T value) {
+        return 0; // -1 if doesnt contain
+    }
+
+    public int size() {
+        return size;
+    }
+
+    public T[] toArray() {
+        return null;
+    }
+
+    public T[] getOriginalArray() {
+        return originalArray;
+    }
+
+    public void setOriginalArray(T[] originalArray) {
+        this.originalArray = originalArray;
+    }
+
+    public void setSize(int size) {
+        this.size = size;
+    }
 }

src/test/java/MyArrayListTest.java

@@ -1,2 +1,232 @@
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.lang.reflect.Array;
+import java.util.ArrayList;
+
 public class MyArrayListTest {
+
+    MyArrayList<Integer> testArray = new MyArrayList<>();
+
+    public void populateArray() {
+        testArray.add(10);
+        testArray.add(3);
+        testArray.add(9);
+        testArray.add(2);
+    }
+
+
+    @Test
+    public void test(){
+        Integer[] i = new Integer[0];
+        System.out.println(i.getClass());
+
+        Object[] objects = new Object[0];
+        System.out.println(objects.getClass());
+
+        populateArray();
+        System.out.println(testArray.get(0).getClass());
+
+        MyArrayList<String> testStringArray = new MyArrayList<>();
+        testStringArray.add("Meow");
+        System.out.println(testStringArray.get(0).getClass());
+        // System.out.println(testStringArray.getOriginalArray()[0]);
+    }
+
+    @Test
+    public void initiateSizeOnConstruction() {
+        MyArrayList<Integer> testArray1 = new MyArrayList<>(5);
+
+        int expected = 5;
+        int actual = testArray1.size();
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testAdd() {
+        testArray.add(5);
+
+        int expected = 5;
+        int actual = testArray.get(0);
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testAdd_Size() {
+        testArray.add(5);
+
+        int expected = 1;
+        int actual = testArray.size();
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testAdd_Multiple() {
+        populateArray();
+
+        int expected = 9;
+        int actual = testArray.get(2);
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testAdd_Multiple_String() {
+        MyArrayList<String> testStringArray = new MyArrayList<>();
+        testStringArray.add("Jenn");
+        testStringArray.add("Ned");
+
+        String expected = "Ned";
+        String actual = testStringArray.get(1);
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testAdd_Multiple_String_Size() {
+        MyArrayList<String> testStringArray = new MyArrayList<>();
+        testStringArray.add("Jenn");
+        testStringArray.add("Ned");
+        testStringArray.add("Thulasi");
+
+        int expected = 3;
+        int actual = testStringArray.size();
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testAdd_Multiple_Size() {
+        populateArray();
+
+        int expected = 4;
+        int actual = testArray.size();
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testAdd_AtIndex() {
+        populateArray();
+        testArray.add(5, 2);
+
+        int expected = 5;
+        int actual = testArray.get(2);
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testAdd_AtIndex_Size() {
+        populateArray();
+        testArray.add(5, 2);
+
+        int expected = 5;
+        int actual = testArray.size();
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testRemove_First() {
+        populateArray();
+        testArray.remove(10);
+
+        int unexpected = 10;
+        int actual = testArray.get(0);
+
+        Assert.assertNotEquals(unexpected, actual);
+    }
+
+    @Test
+    public void testRemove_Middle() {
+        populateArray();
+        testArray.remove(9);
+
+        int expected = 2;
+        int actual = testArray.get(2);
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testRemove_Size() {
+        populateArray();
+        testArray.remove(2);
+
+        int expected = 3;
+        int actual = testArray.size();
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testIsEmpty_True() {
+        Assert.assertTrue(testArray.isEmpty());
+    }
+
+    @Test
+    public void testIsEmpty_False() {
+        populateArray();
+        Assert.assertFalse(testArray.isEmpty());
+    }
+
+    @Test
+    public void testContains_True() {
+        populateArray();
+        Assert.assertTrue(testArray.contains(9));
+    }
+
+    @Test
+    public void testContains_False() {
+        populateArray();
+        Assert.assertFalse(testArray.contains(5));
+    }
+
+    @Test
+    public void testSet() {
+        populateArray();
+        testArray.set(2, 55);
+
+        int expected = 55;
+        int actual = testArray.get(2);
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testSet_Again() {
+        populateArray();
+
+        testArray.set(0, 11);
+
+        int expected = 11;
+        int actual = testArray.get(0);
+
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test(expected = IndexOutOfBoundsException.class)
+    public void testClear() {
+        populateArray();
+        testArray.clear();
+
+        testArray.get(0);
+    }
+
+    @Test
+    public void testClear_Size() {
+        populateArray();
+        testArray.clear();
+
+        int expected = 0;
+        int actual = testArray.size();
+
+        Assert.assertEquals(expected, actual);
+    }
+
+
 }