Fix issue FasterXML#162

Author: Øistein Løvik

src/main/java/com/fasterxml/jackson/dataformat/xml/deser/XmlTokenStream.java

@@ -371,21 +371,23 @@ private final int _next() throws XMLStreamException
 
     private final String _collectUntilTag() throws XMLStreamException
     {
-        String text = null;
+        if (_xmlReader.isEmptyElement()) {
+            _xmlReader.next();
+            return null;
+        }
+
+        StringBuilder text = new StringBuilder();
+
         while (true) {
             switch (_xmlReader.next()) {
             case XMLStreamConstants.START_ELEMENT:
             case XMLStreamConstants.END_ELEMENT:
             case XMLStreamConstants.END_DOCUMENT:
-                return text;
-                // note: SPACE is ignorable (and seldom seen), not to be included
+                return text.toString();
+            // note: SPACE is ignorable (and seldom seen), not to be included
             case XMLStreamConstants.CHARACTERS:
             case XMLStreamConstants.CDATA:
-                if (text == null) {
-                    text = _xmlReader.getText();
-                } else { // can be optimized in future, if need be:
-                    text += _xmlReader.getText();
-                }
+                text.append(_xmlReader.getText());
                 break;
             default:
                 // any other type (proc instr, comment etc) is just ignored

src/test/java/com/fasterxml/jackson/dataformat/xml/failing/TestStringValues162.java renamed to src/test/java/com/fasterxml/jackson/dataformat/xml/deser/TestStringValues162.java

@@ -1,4 +1,4 @@
-package com.fasterxml.jackson.dataformat.xml.failing;
+package com.fasterxml.jackson.dataformat.xml.deser;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -40,6 +40,14 @@ public void testEmptyString162() throws Exception
         assertEquals("", name.last);
     }
 
+    public void testEmptyElement() throws Exception
+    {
+        Name name = MAPPER.readValue("<name><first/><last></last></name>", Name.class);
+        assertNotNull(name);
+        assertNull(name.first);
+        assertEquals("", name.last);
+    }
+
     public void testEmptyStringElement() throws Exception
     {
         // then with empty element