Change Idea id from long to UUID

src/main/java/br/unicamp/cst/representation/idea/Idea.java

@@ -30,6 +30,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.TimeZone;
+import java.util.UUID;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import org.slf4j.LoggerFactory;
@@ -41,7 +42,7 @@
  * @author rgudwin
  */
 public class Idea implements Category,Habit {
-    private long id;
+    private String id;
     private String name;
     private Object value;
     private List<Idea> l= new CopyOnWriteArrayList<>();
@@ -64,7 +65,7 @@ public class Idea implements Category,Habit {
     /**
      * This variable stores the last Id used while creating new Ideas. 
      */
-    public static long lastId = 0;
+    public static String lastId = "";
 
     private static final String CDOUBLE = "java.lang.Double";
     private static final String CFLOAT = "java.lang.Float";
@@ -80,13 +81,13 @@ public class Idea implements Category,Habit {
 
     /**
      * This function generates a new id to be assigned to a new Idea being created. 
-     * This id is generated in a serialized format, being the first one with value 0 
-     * and incrementally increased by one for each new created Idea. The value of the 
+     * This id is generated with UUID(universally unique and reduces risk of conflicts). The value of the 
      * last id created so far is stored in the <i>lastId</i> static variable. 
      * @return the generated new id
      */
-    public static long genId() {
-        return(lastId++);
+    public static String genId() {
+        lastId = UUID.randomUUID().toString();
+        return lastId;
     }
     /**
      * This is the simpler constructor for an Idea. Basically, it finds a new id and creates an empty Idea. 
@@ -343,7 +344,7 @@ public void setL(List<Idea> l) {
      * This method returns the id associated to the current Idea
      * @return the id of the current Idea
      */
-    public long getId() {
+    public String getId() {
         return(id);
     }
 

src/test/java/br/unicamp/cst/representation/idea/TestIdea.java

@@ -356,7 +356,7 @@ public void testIsMethods() {
     public void cloneTest() {
         Object value = new EntityCategory();
         Idea i = new Idea("test",value,12,"category",0.0,0.5);
-        long n1,n2,n3,n4,n5,n6;
+        String n1,n2,n3,n4,n5,n6;
         n1 = i.getId();
         Idea sub1 = new Idea("sub","value1",13,"category1",1.0,0.5);
         n2 = sub1.getId();