Merge branch 'fix-group' into 'master'

[FIX][SDK] exception now throws when one tries to add the same entity to two groups

See merge request codingame/game-engine!268

Author: CodinGameCommunity

engine/modules/entities/src/main/java/com/codingame/gameengine/module/entities/ContainerBasedEntity.java

@@ -8,17 +8,19 @@
 /**
  * 
  *
- * @param <T> a subclass inheriting Entity, used in order to return <b>this</b> as a T instead of a <code>ContainerBasedEntity</code>.
+ * @param <T>
+ *            a subclass inheriting Entity, used in order to return <b>this</b> as a T instead of a <code>ContainerBasedEntity</code>.
  */
 public abstract class ContainerBasedEntity<T extends Entity<?>> extends Entity<T> {
 
     private Set<Entity<?>> entities;
-    
+
     ContainerBasedEntity() {
         super();
 
         entities = new HashSet<>();
     }
+
     /**
      * Separates the given entity from this <code>ContainerBasedEntity</code>.
      * 
@@ -45,19 +47,27 @@ public void remove(Entity<?> entity) {
      */
     public void add(Entity<?>... entities) {
         Stream.of(entities).forEach(entity -> {
-            if (entity.parent != null) {
-                throw new IllegalArgumentException();
+            if (entity.getParent().isPresent()) {
+                throw new IllegalArgumentException(
+                    String.format(
+                        "Cannot add entity %d to container %d: it is already in container %d",
+                        entity.getId(),
+                        getId(),
+                        entity.getParent().get().getId()
+                    )
+                );
             }
             this.entities.add(entity);
+            entity.parent = this;
         });
 
         set("children", asString(this.entities), null);
     }
 
     private String asString(Set<Entity<?>> entities) {
         return entities.stream()
-                .map(e -> String.valueOf(e.getId()))
-                .collect(Collectors.joining(","));
+            .map(e -> String.valueOf(e.getId()))
+            .collect(Collectors.joining(","));
     }
 
 }

engine/modules/entities/src/main/java/com/codingame/gameengine/module/entities/Entity.java

@@ -516,4 +516,11 @@ protected static void requireValidColor(int color) {
             throw new IllegalArgumentException(color + "is not a valid RGB integer.");
         }
     }
+    
+    /**
+     * @return the Group or BufferedGroup which contains this entity
+     */
+    public Optional<ContainerBasedEntity<?>> getParent() {
+        return Optional.ofNullable(parent);
+    }
 }

playground/misc/misc-3-release-notes.md

@@ -2,6 +2,17 @@
 
 The CodinGame SDK is regularly updated and improved. This document lets you know what changed in the latest releases.
 
+## Next Release
+
+### 🎁 Features
+
+- `Entity` now exposes the `getParent` method to acces the container an entity has been added into
+
+### 🐞 Bug fix
+
+- An exception is now thrown when one tries to add the same entity to two different groups
+- `Group::remove` now functions correctly
+
 ## 3.12.0
 
 ### 🎁 Features