added iterator in arraylist and added entrySet method in HashMap

Author: nisabmohd

src/Lists/ArrayListCustom.java

@@ -2,7 +2,6 @@
 
 import java.util.*;
 import java.util.function.Consumer;
-import java.util.function.Function;
 import java.util.function.Predicate;
 
 public class ArrayListCustom<T> implements Cloneable {
@@ -123,6 +122,7 @@ public void forEach(Consumer<T> o) {
     }
 
     public ArrayListCustom<T> filter(Predicate<T> o) {
+        Objects.requireNonNull((o));
         ArrayListCustom<T> newList = new ArrayListCustom<>();
         this.forEach((item) -> {
             if (o.test(item)) {
@@ -132,6 +132,21 @@ public ArrayListCustom<T> filter(Predicate<T> o) {
         return newList;
     }
 
+    //hh
+    private class ArrayListItr<T> implements Iterator<T> {
+        int cursor = 0;
+
+        @Override
+        public boolean hasNext() {
+            return cursor < ArrayListCustom.this.size;
+        }
+
+        @Override
+        public T next() {
+            return (T) ArrayListCustom.this.arr[cursor++];
+        }
+    }
+
     public Object[] toArray() {
         Object[] ret = new Object[size];
         for (int i = 0; i < size; i++) {

src/Maps/HashMapCustom.java

@@ -2,27 +2,36 @@
 //check out my medium blog for hashmap
 //https://medium.com/@nisabmohd/hashmap-in-java-c010dec8fbd0
 
-import java.util.Objects;
+import java.util.*;
 import java.util.function.BiConsumer;
+import java.util.function.Consumer;
 
 public class HashMapCustom<K, V> {
 
     private final int DEFAULT_CAPACITY = 17;
     private final Entry[] bucket = new Entry[DEFAULT_CAPACITY];
     private int size = 0;
 
-    private class Entry<K, V> {
+    public class Entry<K, V> {
 
-        K key;
-        V val;
-        Entry next;
+        private K key;
+        private V val;
+        private Entry next;
 
         public Entry(K key, V val, Entry next) {
             this.key = key;
             this.val = val;
             this.next = next;
         }
 
+        public K getKey() {
+            return this.key;
+        }
+
+        public V getValue() {
+            return this.val;
+        }
+
     }
 
     private int hashCode(K key) {
@@ -135,6 +144,17 @@ public void forEach(BiConsumer<K, V> o) {
         }
     }
 
+    public void forEachEntry(Consumer<Entry<K, V>> o) {
+        Objects.requireNonNull(o);
+        for (int i = 0; i < bucket.length; i++) {
+            Entry temp = bucket[i];
+            while (temp != null) {
+                o.accept(temp);
+                temp = temp.next;
+            }
+        }
+    }
+
     @Override
     public String toString() {
         StringBuilder builder = new StringBuilder("{");
@@ -167,4 +187,12 @@ public Object[] toKeyArray() {
         return t;
     }
 
+    public Set<Entry<K, V>> entrySet() {
+        Set<Entry<K, V>> set = new HashSet<>();
+        forEachEntry(entry -> {
+            set.add(entry);
+        });
+        return set;
+    }
+
 }