diff --git a/com/xgiovio/NodeSequenceTest.java b/com/xgiovio/NodeSequenceTest.java
new file mode 100644
index 0000000..633c064
--- /dev/null
+++ b/com/xgiovio/NodeSequenceTest.java
@@ -0,0 +1,66 @@
+package com.xgiovio;
+
+import arraylist.ArrayIndexList;
+import general_utility.test_object;
+import sequence.NodeSequence;
+
+/**
+ * Created with xgiovio.macbookair.
+ * User: xgiovio
+ * Date: 23/03/14
+ * Time: 20:37
+ */
+public class NodeSequenceTest {
+
+    public static void main(String[] args) {
+        NodeSequence<test_object> a = new NodeSequence<test_object>();
+
+        System.out.print(a);
+
+        a.add(0,new test_object(1));
+
+        System.out.print(a);
+
+        a.add(1,new test_object(2));
+
+
+        System.out.print(a);
+
+        a.add(2,new test_object(3));
+        System.out.print(a);
+        a.add(3,new test_object(4));
+
+        System.out.print(a);
+        a.remove(2);
+        System.out.print(a);
+
+        a.add(0,new test_object(4));
+
+        System.out.print(a);
+        a.add(3,new test_object(10));
+
+        System.out.print(a);
+        a.add(4,new test_object(11));
+
+        System.out.print(a);
+        a.add(6,new test_object(100));
+
+        System.out.print(a);
+
+        a.set(0,new test_object(100));
+
+        System.out.print(a);
+        a.set(6,new test_object(200));
+
+        System.out.print(a);
+
+
+
+
+
+
+
+
+    }
+
+}
diff --git a/exceptions/EmptyDequeException.java b/exceptions/EmptyDequeException.java
index e8f2afa..c786f29 100644
--- a/exceptions/EmptyDequeException.java
+++ b/exceptions/EmptyDequeException.java
@@ -11,4 +11,7 @@ public class EmptyDequeException extends RuntimeException {
     public EmptyDequeException(){
         super("Deque Empty");
     }
+    public EmptyDequeException(String msg){
+        super(msg);
+    }
 }
diff --git a/exceptions/EmptyQueueException.java b/exceptions/EmptyQueueException.java
index 0a7c7e1..2a5acc1 100644
--- a/exceptions/EmptyQueueException.java
+++ b/exceptions/EmptyQueueException.java
@@ -11,4 +11,7 @@ public class EmptyQueueException extends RuntimeException {
     public EmptyQueueException(){
         super("Queue Empty");
     }
+    public EmptyQueueException(String msg){
+        super(msg);
+    }
 }
diff --git a/exceptions/EmptySequenceException.java b/exceptions/EmptySequenceException.java
new file mode 100644
index 0000000..648f761
--- /dev/null
+++ b/exceptions/EmptySequenceException.java
@@ -0,0 +1,18 @@
+package exceptions;
+
+/**
+ * Signals that the boundaries of a data structure have been illegally
+ * traversed (e.g. past the end of a list).
+ * @author Roberto Tamassia
+ */
+//Copyright (c) 2003 Brown University, Providence, RI
+//Additional modifications and methods by xgiovio
+
+public class EmptySequenceException extends RuntimeException {
+  public EmptySequenceException(String message) {
+    super (message);
+  }
+    public EmptySequenceException() {
+        super ("EmptySequenceException");
+    }
+}
diff --git a/exceptions/EmptyStackException.java b/exceptions/EmptyStackException.java
index 7813f7b..2f3d29f 100644
--- a/exceptions/EmptyStackException.java
+++ b/exceptions/EmptyStackException.java
@@ -11,4 +11,7 @@ public class EmptyStackException extends RuntimeException {
     public EmptyStackException(){
         super("Stack Empty");
     }
+    public EmptyStackException(String msg){
+        super(msg);
+    }
 }
diff --git a/position/PositionList.java b/position/PositionList.java
index 0d534d1..fd16f47 100644
--- a/position/PositionList.java
+++ b/position/PositionList.java
@@ -15,9 +15,9 @@ public interface PositionList<E>  {
 
   public boolean isEmpty();
 
-  public Position<E> first();
+  public Position<E> first() throws EmptyListException;
 
-  public Position<E> last();
+  public Position<E> last() throws EmptyListException;
 
   public Position<E> next(Position<E> p)      throws InvalidPositionException, BoundaryViolationException;
 
diff --git a/sequence/NodeSequence.java b/sequence/NodeSequence.java
new file mode 100644
index 0000000..7da205b
--- /dev/null
+++ b/sequence/NodeSequence.java
@@ -0,0 +1,175 @@
+package sequence;
+
+import exceptions.BoundaryViolationException;
+import exceptions.EmptyListException;
+import exceptions.EmptySequenceException;
+import exceptions.InvalidPositionException;
+import position.NodePositionList;
+import position.Position;
+
+/**
+ * Created with MONSTER.
+ * User: xgiovio
+ * Date: 30/03/2014
+ * Time: 14:35
+ */
+public class NodeSequence <E> extends NodePositionList<E> implements Sequence<E> {
+
+    @Override
+    public E getFirst() throws EmptySequenceException {
+        try {
+            Position<E> t = first();
+            return t.element();
+        }
+        catch (EmptyListException e){
+            throw new EmptySequenceException();
+        }
+    }
+
+    @Override
+    public E getLast() throws EmptySequenceException {
+        try {
+            Position<E> t = last();
+            return t.element();
+        }
+        catch (EmptyListException e){
+            throw new EmptySequenceException();
+        }
+    }
+
+    @Override
+    public E removeFirst() throws EmptySequenceException {
+        try {
+            Position<E> t = first();
+            E ele = remove(t);
+            return ele;
+        }
+        catch (EmptyListException e){
+            throw new EmptySequenceException();
+        }
+    }
+
+    @Override
+    public E removeLast() throws EmptySequenceException {
+        try {
+            Position<E> t = last();
+            E ele = remove(t);
+            return ele;
+        }
+        catch (EmptyListException e){
+            throw new EmptySequenceException();
+        }
+    }
+
+    @Override // si potrebbe anche andare indietro a partire dall'ultimo
+    public Position<E> atIndex(int index) throws BoundaryViolationException {
+        try {
+            checkIndex(index, size());
+            Position<E> t = first();
+            for (int i = 0; i < index; i++) {
+                t = next(t);
+            }
+            return t;
+        }
+        catch (IndexOutOfBoundsException e){
+            throw new BoundaryViolationException();
+        }
+
+    }
+
+    @Override
+    public int indexOf(Position<E> position) throws InvalidPositionException {
+        checkPosition(position);
+        Position<E> t = first();
+        int i ;
+        for (i = 0 ;t != position;i++){
+            t= next(t);
+        }
+        return i;
+
+    }
+
+    @Override
+    public E remove(int i) throws IndexOutOfBoundsException {
+        checkIndex(i,size());
+        E ele = remove(atIndex(i));
+        return  ele;
+
+    }
+
+    @Override
+    public void add(int i, E e) throws IndexOutOfBoundsException {
+        try {
+            checkIndex(i,size()+1);
+            if (i == 0){
+                addFirst(e);
+            } else {
+                if ( i== size()){
+                    addLast(e);
+                }else {
+                    Position<E> t = atIndex(i);
+                    addBefore(t, e);
+                }
+            }
+        }
+        catch (BoundaryViolationException err){
+            throw new IndexOutOfBoundsException ();
+        }
+
+    }
+
+    @Override
+    public E set(int i, E e) throws IndexOutOfBoundsException {
+        try {
+            Position<E> t = atIndex(i);
+            E ele = set(t,e);
+            return ele;
+        }
+        catch (BoundaryViolationException err){
+            throw new IndexOutOfBoundsException ();
+        }
+    }
+
+    @Override
+    public E get(int i) throws IndexOutOfBoundsException {
+        try {
+            Position<E> t = atIndex(i);
+            return t.element();
+        }
+        catch (BoundaryViolationException err){
+            throw new IndexOutOfBoundsException ();
+        }
+    }
+
+
+    protected void checkIndex(int r, int n)  throws IndexOutOfBoundsException {
+        if (r < 0 || r >= n)
+            throw new IndexOutOfBoundsException("Illegal index: " + r);
+    }
+
+    @Override
+    public String toString() {
+        String to_return = "";
+        to_return = to_return + "[";
+        if (size() > 0) {
+            int i;
+            Position<E> temp;
+            for (temp = first(), i = 0;true;) {
+
+                if ( i == size() - 1) {
+                    to_return += (temp.element().toString());
+                } else {
+                    to_return += (temp.element().toString() + ",");
+                }
+                if (i == size() - 1){
+                    break;
+                }else{
+                   i++;
+                   temp = next(temp);
+                }
+            }
+        }
+        to_return = to_return + "]";
+        return to_return;
+    }
+}
diff --git a/sequence/Sequence.java b/sequence/Sequence.java
new file mode 100644
index 0000000..013eedc
--- /dev/null
+++ b/sequence/Sequence.java
@@ -0,0 +1,24 @@
+package sequence;
+
+import arraylist.IndexList;
+import position.Position;
+import position.PositionList;
+import exceptions.*;
+
+/**
+ * Created with MONSTER.
+ * User: xgiovio
+ * Date: 30/03/2014
+ * Time: 14:31
+ */
+public interface Sequence<E> extends PositionList<E>, IndexList<E> {
+    public E getFirst() throws EmptySequenceException;
+    public E getLast()  throws  EmptySequenceException;
+    public E removeFirst() throws  EmptySequenceException;
+    public E removeLast() throws EmptySequenceException;
+
+    public Position<E> atIndex(  int  index)  throws  BoundaryViolationException;
+    public int  indexOf(Position <E> position) throws InvalidPositionException;
+
+
+}