OO-3546: show the number of files in directories in the folder component

(patch S. Clemenz)

src/main/java/org/olat/core/commons/modules/bc/_i18n/LocalStrings_de.properties

@@ -86,6 +86,7 @@ mf.author=Autor
 mf.cancel=Abbrechen
 mf.comment=Beschreibung
 mf.edit=Metadaten bearbeiten
+mf.elements=Element(e)
 mf.error.filename.empty=Der Name des Objektes darf nicht leer sein.
 mf.error.filename.exists=Es gibt bereits ein Objekt mit diesem Namen.
 mf.error.filename.invalidchars=Der Name des Objekts enth\u00E4lt ung\u00FCltige Zeichen.

src/main/java/org/olat/core/commons/modules/bc/_i18n/LocalStrings_en.properties

@@ -86,6 +86,7 @@ mf.author=Author
 mf.cancel=Cancel
 mf.comment=Description
 mf.edit=Edit metadata
+mf.elements=element(s)
 mf.error.filename.empty=You have to enter a name for this object.
 mf.error.filename.exists=An object with this name already exists.
 mf.error.filename.invalidchars=Name of object contains invalid characters.

src/main/java/org/olat/core/commons/modules/bc/components/ListRenderer.java

@@ -61,6 +61,7 @@ import org.olat.core.util.vfs.VFSItem;
 import org.olat.core.util.vfs.VFSLeaf;
 import org.olat.core.util.vfs.VFSLockManager;
 import org.olat.core.util.vfs.VirtualContainer;
+import org.olat.core.util.vfs.filters.SystemItemFilter;
 import org.olat.core.util.vfs.lock.LockInfo;
 import org.olat.core.util.vfs.version.Versionable;
 import org.olat.core.util.vfs.version.Versions;
@@ -357,6 +358,11 @@ public class ListRenderer {
 			sb.append(Formatter.formatBytes(leaf.getSize()));
 			sb.append("</span>");
 		}
+		else if (child instanceof VFSContainer) {
+			sb.append("<span class='text-muted small'>");
+			sb.append(((VFSContainer) child).getItems(new SystemItemFilter()).size());
+			sb.append(" "+translator.translate("mf.elements")+"</span>");
+		}
 		sb.append("</td><td>");
 		
 		// last modified