refactor(core/TicketBuilder): make assignees setter non abstract and use string

src/main/java/de/hftstuttgart/unifiedticketing/core/TicketBuilder.java

@@ -20,7 +20,7 @@ public abstract class TicketBuilder<B extends TicketBuilder, T extends Ticket, T
 
     public final TS parent;
 
-    protected Set<Integer> assignees;
+    protected Set<String> assignees;
     protected String description;
     protected Set<String> labels;
     protected String title;
@@ -37,7 +37,11 @@ public abstract class TicketBuilder<B extends TicketBuilder, T extends Ticket, T
         logger.log(Level.FINEST, String.format("%s instantiated", this.getClass().getSimpleName()));
     }
 
-    public abstract B assignees(String... identifiers);
+    public B assignees(String... identifiers)
+    {
+        this.assignees = new HashSet<>(Arrays.asList(identifiers));
+        return (B) this;
+    }
 
     public B description(String description)
     {

src/main/java/de/hftstuttgart/unifiedticketing/systems/gitlab/GitlabTicketBuilder.java

@@ -29,12 +29,10 @@ public class GitlabTicketBuilder extends TicketBuilder<GitlabTicketBuilder, Gitl
     @Override
     public GitlabTicketBuilder assignees(String... identifiers)
     {
-
         try
         {
-            assignees(Arrays.stream(identifiers)
-                .mapToInt(Integer::parseInt)
-                .toArray());
+            Arrays.stream(identifiers)
+                .forEach(Integer::parseInt);
 
         } catch (NumberFormatException e)
         {
@@ -42,15 +40,14 @@ public class GitlabTicketBuilder extends TicketBuilder<GitlabTicketBuilder, Gitl
             throw new AssertionException(e);
         }
 
-        return this;
+        return super.assignees(identifiers);
     }
 
     public GitlabTicketBuilder assignees(int... identifiers)
     {
-        assignees = Arrays.stream(identifiers)
-            .mapToObj(i -> (Integer) i)
-            .collect(Collectors.toSet());
-        return this;
+        return super.assignees(Arrays.stream(identifiers)
+            .mapToObj(String::valueOf)
+            .toArray(String[]::new));
     }
 
     protected OkHttpClient getHttpClient() { return new OkHttpClient(); }
@@ -83,7 +80,10 @@ public class GitlabTicketBuilder extends TicketBuilder<GitlabTicketBuilder, Gitl
         if (this.assignees != null)
         {
             ArrayNode ids = body.putArray("assignee_ids");
-            assignees.forEach(ids::add);
+            assignees
+                .stream()
+                .mapToInt(Integer::parseInt)
+                .forEach(ids::add);
             logger.log(Level.FINEST, "assignees set");
         }