フォルダの一覧を取得するメソッド作成

data/src/main/java/one/nem/lacerta/data/LacertaLibrary.java

@@ -20,6 +20,9 @@ public interface LacertaLibrary {
     CompletableFuture<LibraryItemPage> getLibraryPage(String pageId, int limit);
     CompletableFuture<LibraryItemPage> getLibraryPage(String pageId, int limit, int offset);
 
+    // Get Folder List
+    CompletableFuture<ArrayList<ListItem>> getFolderList(String parentId);
+
     // Create Folder
     CompletableFuture<String> createFolder(String parentId, String name);
 

data/src/main/java/one/nem/lacerta/data/impl/LacertaLibraryImpl.java

@@ -127,6 +127,31 @@ public class LacertaLibraryImpl implements LacertaLibrary {
         });
     }
 
+    @Override
+    public CompletableFuture<ArrayList<ListItem>> getFolderList(String parentId) {
+        return CompletableFuture.supplyAsync(() -> {
+            List<FolderEntity> folderEntities;
+            if (parentId == null) { // When root folder
+                folderEntities = database.folderDao().findRootFolders();
+            } else {
+                folderEntities = database.folderDao().findByParentId(parentId);
+            }
+
+            ArrayList<ListItem> listItems = new ArrayList<>();
+            for (FolderEntity childFolderEntity : folderEntities) {
+                logger.debug("LacertaLibraryImpl", "childFolderEntity.name: " + childFolderEntity.name);
+                ListItem listItem = new ListItem();
+                listItem.setItemType(ListItemType.ITEM_TYPE_FOLDER);
+                listItem.setTitle(childFolderEntity.name);
+                listItem.setDescription("フォルダ"); // TODO-rca: ハードコーディングやめる
+                listItem.setItemId(childFolderEntity.id);
+                listItems.add(listItem);
+            }
+
+            return listItems;
+        });
+    }
+
     @Override
     public CompletableFuture<String> createFolder(String parentId, String name) {
         return CompletableFuture.supplyAsync(() -> {