diff --git a/jlib/Sequence.java b/jlib/Sequence.java
new file mode 100644
index 0000000..6b2cd95
--- /dev/null
+++ b/jlib/Sequence.java
@@ -0,0 +1,33 @@
+package jlib;
+
+import java.util.HashSet;
+import java.util.LinkedList;
+
+public class Sequence<T> {
+	private LinkedList<T> previous;
+	private Integer max;
+
+	public Sequence(Integer size) {
+		this.max = size;
+		this.previous = new LinkedList<T>();
+	}
+
+	public void add(T e) {
+		if (this.previous.size() == this.max) {
+			this.previous.pop();
+		}
+		this.previous.add(e);
+	}
+
+	public Integer size() {
+		return this.previous.size();
+	}
+
+	public Boolean isUnique() {
+		HashSet<T> s = new HashSet<>();
+		for (T e : this.previous) {
+			s.add(e);
+		}
+		return s.size() == this.max;
+	}
+}