Improve json to xml converter with attribute on top level.

Author: javadev

src/main/java/com/github/underscore/lodash/U.java

@@ -2050,7 +2050,7 @@ public static class XmlObject {
         @SuppressWarnings("unchecked")
         public static void writeXml(Map map, String name, XmlStringBuilder builder, boolean parentTextFound) {
             if (map == null) {
-                builder.append(NULL);
+                XmlValue.writeXml(map, name, builder, false);
                 return;
             }
 
@@ -2322,15 +2322,14 @@ public String toXml() {
     }
 
     public static String toXml(Map map) {
-        final XmlStringBuilder builder;
-        if ((map == null || map.size() != 1)
+        final XmlStringBuilder builder = new XmlStringBuilderWithoutRoot();
+        if (map == null || map.size() != 1
+            || ((String) ((Map.Entry) map.entrySet().iterator().next()).getKey()).startsWith("-")
             || ((Map.Entry) map.entrySet().iterator().next()).getValue() instanceof List) {
-            builder = new XmlStringBuilder();
+            XmlObject.writeXml(map, "root", builder, false);
         } else {
-            builder = new XmlStringBuilderWithoutRoot();
+            XmlObject.writeXml(map, null, builder, false);
         }
-
-        XmlObject.writeXml(map, null, builder, false);
         return builder.toString();
     }
 

src/test/java/com/github/underscore/lodash/StringTest.java

@@ -1308,7 +1308,7 @@ public void toXmlFromMap() {
         assertEquals("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<root>\n"
             + "  <First__EA__item>1</First__EA__item>\n  <Second__EA__item>2</Second__EA__item>\n</root>",
             U.toXml(testMap));
-        assertEquals("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<root>\nnull\n</root>", U.toXml((Map) null));
+        assertEquals("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<root>null</root>", U.toXml((Map) null));
         assertEquals("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<root>\n  <item>\n"
                 + "  </item>\n</root>", U.toXml(testMap2));
         assertEquals("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<__EE__EMPTY__EE__>1"
@@ -1652,6 +1652,15 @@ public void toXmlFromJson10() {
                 U.toXml((Map<String, Object>) U.fromJson(json2)));
     }
 
+    @SuppressWarnings("unchecked")
+    @Test
+    public void toXmlFromJson11() {
+        final String json = "{\n  \"-id\": 1\n}";
+        assertEquals("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+                + "<root>\n  <__FU__id>1</__FU__id>\n</root>",
+                U.toXml((Map<String, Object>) U.fromJson(json)));
+    }
+
     @SuppressWarnings("unchecked")
     @Test
     public void toXml() {