Add linked list for java

linkedlist/java/LinkedList.java

@@ -0,0 +1,93 @@
+import  java.lang.*;
+
+public class List {
+
+    class Node {
+
+        int key;
+        Node next;
+
+        public Node (int key){
+            this.key = key;
+        }
+
+        public void print() {
+            System.out.println ("Key: " + key);
+            System.out.println ("Next: " + next);
+        }
+    }
+
+    Node head;
+
+    public List (Node head){
+        this.head = head;
+    }
+
+    public boolean isEmpty(){
+        return head.next == null;
+    }
+
+    public boolean exists (int key) {
+        Node current = head;
+        while (current != null){
+            if (current.key == key) return true;
+            current = current.next;
+        }
+        return false;
+    }
+
+    public void insertAtHead (Node toInsert){
+        toInsert.next = head.next;
+        head.next = toInsert;
+    }
+
+    public void insertAtTail (Node toInsert){
+        Node current = head;
+        while (current.next != null){
+            current = current.next;
+        }
+        current.next = toInsert;
+        toInsert.next = null;
+    }
+
+    public void insertAfterKey (int key, Node toInsert){
+        Node current = head;
+        if (!exists(key)) System.out.println ("Key not found.");
+        else {
+            while (current.key != key){
+                current = current.next;
+            }
+            toInsert.next = current.next;
+            current.next = toInsert;
+        }
+    }
+
+    public Node getElement(int pos){
+        Node current = head;
+        for (int i = 1; i <= pos; i++){
+            current = current.next;
+        }
+        return current;
+    }
+
+    public int countElements (){
+        Node current = head;
+        int counter = 0;
+        while (current != null){
+            counter++;
+            current = current.next;
+        }
+        return counter;
+    }
+
+    public void printList (){
+        Node current = head;
+        while (current != null){
+            System.out.println ("Key:  " + current.key);
+            if (current.next == null) System.out.println ("Last Node.");
+            else System.out.println ("Next: " + current.next.key);
+            current = current.next;
+        }
+        System.out.print (countElements() + " Elements in this List.");
+    }
+}