updated class ArrayList

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

@@ -1,48 +1,116 @@
 package core.basesyntax;
 
+import java.util.NoSuchElementException;
+
 public class ArrayList<T> implements List<T> {
+
+    private static final int DEFAULT_CAPACITY = 10;
+
+    private Object[] elements;
+
+    private int size;
+
+    public ArrayList() {
+        elements = new Object[DEFAULT_CAPACITY];
+    }
+
     @Override
     public void add(T value) {
-
+        growIfFull();
+        elements[size] = value;
+        size++;
     }
 
     @Override
     public void add(T value, int index) {
+        checkIndexForAdd(index);
+        growIfFull();
 
+        System.arraycopy(elements, index, elements, index + 1, size - index);
+
+        elements[index] = value;
+        size++;
     }
 
     @Override
     public void addAll(List<T> list) {
-
+        for (int i = 0; i < list.size(); i++) {
+            add(list.get(i));
+        }
     }
 
     @Override
+    @SuppressWarnings("unchecked")
     public T get(int index) {
-        return null;
+        checkIndex(index);
+        return (T) elements[index];
     }
 
     @Override
     public void set(T value, int index) {
-
+        checkIndex(index);
+        elements[index] = value;
     }
 
     @Override
+    @SuppressWarnings("unchecked")
     public T remove(int index) {
-        return null;
+        checkIndex(index);
+        final T removed = (T) elements[index];
+        System.arraycopy(elements, index + 1, elements, index, size - index - 1);
+
+        elements[size - 1] = null;
+        size--;
+        return removed;
     }
 
     @Override
+    @SuppressWarnings("unchecked")
     public T remove(T element) {
-        return null;
+        for (int i = 0; i < size; i++) {
+            T current = (T) elements[i];
+
+            if (current == element
+                    || current != null && current.equals(element)) {
+                return remove(i);
+            }
+        }
+        throw new NoSuchElementException("Element not found: " + element);
     }
 
     @Override
     public int size() {
-        return 0;
+        return size;
     }
 
     @Override
     public boolean isEmpty() {
-        return false;
+        return size == 0;
+    }
+
+    private void growIfFull() {
+        if (size == elements.length) {
+            int newCapacity = elements.length + elements.length / 2;
+            Object[] newElements = new Object[newCapacity];
+
+            System.arraycopy(elements, 0, newElements, 0, size);
+            elements = newElements;
+        }
+    }
+
+    private void checkIndex(int index) {
+        if (index < 0 || index >= size) {
+            throw new ArrayListIndexOutOfBoundsException(
+                    "Index: " + index + ", Size: " + size
+            );
+        }
+    }
+
+    private void checkIndexForAdd(int index) {
+        if (index < 0 || index > size) {
+            throw new ArrayListIndexOutOfBoundsException(
+                    "Index: " + index + ", Size: " + size
+            );
+        }
     }
 }