task jv-array-list is done

src/main/java/core/basesyntax/ArrayList.java

@@ -1,14 +1,62 @@
 package core.basesyntax;
 
+import java.util.Arrays;
+import java.util.NoSuchElementException;
+
 public class ArrayList<T> implements List<T> {
+    private static final int DEFAULT_CAPACITY = 2;
+    private int size;
+    private Object[] elementData;
+
+    public ArrayList() {
+        elementData = new Object[DEFAULT_CAPACITY];
+    }
+
+    public void rangeCheck() {
+        if (size == elementData.length) {
+            grow();
+        }
+    }
+
+    public void indexCheck(int index) {
+        if (index >= size || index < 0) {
+            throw new ArrayListIndexOutOfBoundsException("Invalid index");
+        }
+    }
+
+    private Object[] grow() {
+        int newCapacity = elementData.length * 3 / 2 + 1;
+        elementData = Arrays.copyOf(elementData, newCapacity);
+        return elementData;
+    }
+
+    public void checkIfElementExists(T element) {
+        boolean elementFaunded = false;
+        for (int i = 0; i < size; i++) {
+            if ((element == null && elementData[i] == null)
+                    || (element != null && element.equals(elementData[i]))) {
+                elementFaunded = true;
+                break;
+            }
+        }
+        if (!elementFaunded) {
+            throw new NoSuchElementException("Element not found in the array");
+        }
+    }
+
     @Override
     public void add(T value) {
-
+        rangeCheck();
+        elementData[size] = value;
+        size++;
     }
 
     @Override
     public void add(T value, int index) {
-
+        if (index > size || index < 0) {
+            throw new ArrayListIndexOutOfBoundsException("Index out of bound ... )");
+        }
+        rangeCheck();
     }
 
     @Override
@@ -18,31 +66,52 @@ public void addAll(List<T> list) {
 
     @Override
     public T get(int index) {
-        return null;
+        indexCheck(index);
+        checkIfElementExistsByIndex(index);
+        return (T) elementData[index];
     }
 
+    private void checkIfElementExistsByIndex(int index) {
+        if (elementData[index] == null) {
+            throw new RuntimeException("There is no element by this index. Please call to admin to support");
+        }
+    }
+
+
     @Override
     public void set(T value, int index) {
 
     }
 
     @Override
     public T remove(int index) {
-        return null;
+        indexCheck(index);
+        final T removedElement = (T) elementData[index];
+        System.arraycopy(elementData, index + 1, elementData, index, size - index - 1);
+        elementData[size - 1] = null;
+        size--;
+        return removedElement;
     }
 
     @Override
     public T remove(T element) {
+        checkIfElementExists(element);
+        for (int i = 0; i < size; i++) {
+            if ((element == null && elementData[i] == null) || (element != null && element.equals(elementData[i]))) {
+                T removedElement = remove(i);
+                return removedElement;
+            }
+        }
         return null;
     }
 
     @Override
     public int size() {
-        return 0;
+        return size;
     }
 
     @Override
     public boolean isEmpty() {
-        return false;
+        return size == 0;
     }
 }