completed jv-array-list

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 T[] elements;
+    private int size;
+
+    public ArrayList() {
+        elements = (T[]) new Object[DEFAULT_CAPACITY];
+    }
+
     @Override
     public void add(T value) {
-
+        if (size == elements.length) {
+            growArray();
+        }
+        elements[size++] = value;
     }
 
     @Override
     public void add(T value, int index) {
-
+        if (index < 0 || index > size) {
+            throw new ArrayListIndexOutOfBoundsException("Index is out of bounds");
+        }
+        if (size == elements.length) {
+            growArray();
+        }
+        for (int i = size - 1; i >= index; i--) {
+            elements[i + 1] = elements[i];
+        }
+        elements[index] = value;
+        size++;
     }
 
     @Override
     public void addAll(List<T> list) {
-
+        for (int i = 0; i < list.size(); i++) {
+            add(list.get(i));
+        }
     }
 
     @Override
     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
     public T remove(int index) {
-        return null;
+        checkIndex(index);
+        T removedElement = (T) elements[index];
+        for (int i = index; i < size - 1; i++) {
+            elements[i] = elements[i + 1];
+        }
+        size--;
+        return removedElement;
     }
 
     @Override
     public T remove(T element) {
-        return null;
+        int index = indexOf(element);
+
+        if (index == -1) {
+            throw new NoSuchElementException("Element not found");
+        }
+        return remove(index);
     }
 
     @Override
     public int size() {
-        return 0;
+        return size;
     }
 
     @Override
     public boolean isEmpty() {
-        return false;
+        return size == 0;
+    }
+
+    private void growArray() {
+        T[] newArray = (T[]) new Object[elements.length * 3 / 2];
+        System.arraycopy(elements, 0, newArray, 0, size);
+        elements = newArray;
+    }
+
+    private int indexOf(T element) {
+        for (int i = 0; i < size; i++) {
+            if (elements[i] == element || elements[i] != null && elements[i].equals(element)) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    private void checkIndex(int index) {
+        if (index < 0 || index >= size) {
+            throw new ArrayListIndexOutOfBoundsException("Index is out of bounds: " + index);
+        }
     }
 }