implemented class ArrayList

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

@@ -1,48 +1,107 @@
 package core.basesyntax;
 
+import java.util.NoSuchElementException;
+
 public class ArrayList<T> implements List<T> {
+    private static final int DEFAULT_CAPACITY = 10;
+    private static final double MIN_CAPACITY = 1.5;
+    private Object[] elementData;
+    private int size;
+
+    public ArrayList() {
+        elementData = new Object[DEFAULT_CAPACITY];
+    }
+
     @Override
     public void add(T value) {
-
+        growIfArrayFull();
+        elementData[size] = value;
+        size++;
     }
 
     @Override
     public void add(T value, int index) {
-
+        if (index < 0 || index > size) {
+            throw new ArrayListIndexOutOfBoundsException("incorrect index");
+        }
+        growIfArrayFull();
+        System.arraycopy(elementData, index, elementData, index + 1, size - index);
+        elementData[index] = value;
+        size++;
     }
 
     @Override
     public void addAll(List<T> list) {
-
+        growIfArrayFull();
+        for (int i = 0; i < list.size(); i++) {
+            growIfArrayFull();
+            this.elementData[size] = list.get(i);
+            size++;
+        }
     }
 
     @Override
     public T get(int index) {
-        return null;
+        if (index < 0 || index >= size) {
+            throw new ArrayListIndexOutOfBoundsException("incorrect index");
+        }
+        return (T) elementData[index];
     }
 
     @Override
     public void set(T value, int index) {
-
+        if (index < 0 || index >= size) {
+            throw new ArrayListIndexOutOfBoundsException("incorrect index");
+        }
+        elementData[index] = value;
     }
 
     @Override
     public T remove(int index) {
-        return null;
+        if (index < 0 || index >= size) {
+            throw new ArrayListIndexOutOfBoundsException("incorrect index");
+        }
+        Object removedElement = elementData[index];
+        System.arraycopy(elementData, index + 1, elementData, index, size - index - 1);
+        size--;
+        return (T) removedElement;
     }
 
     @Override
     public T remove(T element) {
-        return null;
+        int position = index(element);
+        if (position < 0) {
+            throw new NoSuchElementException("element does not exist");
+        }
+        Object removedElement = remove(position);
+        return (T) removedElement;
     }
 
     @Override
     public int size() {
-        return 0;
+        return size;
     }
 
     @Override
     public boolean isEmpty() {
-        return false;
+        return size == 0;
+    }
+
+    public int index(T element) {
+        for (int i = 0; i < size; i++) {
+            if ((element == elementData[i])
+                    || (element != null && element.equals(elementData[i]))) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    private void growIfArrayFull() {
+        if (elementData.length == size) {
+            Object[] newArray = new Object[(int) (elementData.length * MIN_CAPACITY)];
+            System.arraycopy(elementData, 0, newArray, 0, size);
+            elementData = newArray;
+        }
     }
 }