Close XML tag explicitly for empty tags with configuration.

src/main/java/org/json/XML.java

@@ -877,12 +877,25 @@ private static String toString(final Object object, final String tagName, final
                         }
                     }
                 } else if ("".equals(value)) {
-                    sb.append(indent(indent));
-                    sb.append('<');
-                    sb.append(key);
-                    sb.append("/>");
-                    if(indentFactor > 0){
-                        sb.append("\n");
+                    if (config.isCloseEmptyTag()){
+                        sb.append(indent(indent));
+                        sb.append('<');
+                        sb.append(key);
+                        sb.append(">");
+                        sb.append("</");
+                        sb.append(key);
+                        sb.append(">");
+                        if (indentFactor > 0) {
+                            sb.append("\n");
+                        }
+                    }else {
+                        sb.append(indent(indent));
+                        sb.append('<');
+                        sb.append(key);
+                        sb.append("/>");
+                        if (indentFactor > 0) {
+                            sb.append("\n");
+                        }
                     }
 
                     // Emit a new tag <k>

src/main/java/org/json/XMLParserConfiguration.java

@@ -43,6 +43,13 @@ public class XMLParserConfiguration extends ParserConfiguration {
      */
     private boolean convertNilAttributeToNull;
 
+    /**
+     * When creating an XML from JSON Object, an empty tag by default will self-close.
+     * If it has to be closed explicitly, with empty content between start and end tag,
+     * this flag is to be turned on.
+     */
+    private boolean closeEmptyTag;
+
     /**
      * This will allow type conversion for values in XML if xsi:type attribute is defined
      */
@@ -142,15 +149,17 @@ public XMLParserConfiguration (final boolean keepStrings, final String cDataTagN
      *                   xsi:type="integer" as integer,  xsi:type="string" as string
      * @param forceList  <code>new HashSet<String>()</code> to parse the provided tags' values as arrays
      * @param maxNestingDepth <code>int</code> to limit the nesting depth
+     * @param closeEmptyTag <code>boolean</code> to turn on explicit end tag for tag with empty value
      */
     private XMLParserConfiguration (final boolean keepStrings, final String cDataTagName,
             final boolean convertNilAttributeToNull, final Map<String, XMLXsiTypeConverter<?>> xsiTypeMap, final Set<String> forceList,
-            final int maxNestingDepth) {
+            final int maxNestingDepth, final boolean closeEmptyTag) {
         super(keepStrings, maxNestingDepth);
         this.cDataTagName = cDataTagName;
         this.convertNilAttributeToNull = convertNilAttributeToNull;
         this.xsiTypeMap = Collections.unmodifiableMap(xsiTypeMap);
         this.forceList = Collections.unmodifiableSet(forceList);
+        this.closeEmptyTag = closeEmptyTag;
     }
 
     /**
@@ -169,7 +178,8 @@ protected XMLParserConfiguration clone() {
                 this.convertNilAttributeToNull,
                 this.xsiTypeMap,
                 this.forceList,
-                this.maxNestingDepth
+                this.maxNestingDepth,
+                this.closeEmptyTag
         );
     }
 
@@ -303,4 +313,19 @@ public XMLParserConfiguration withForceList(final Set<String> forceList) {
     public XMLParserConfiguration withMaxNestingDepth(int maxNestingDepth) {
         return super.withMaxNestingDepth(maxNestingDepth);
     }
+
+    /**
+     * To enable explicit end tag with empty value.
+     * @param closeEmptyTag
+     * @return same instance of configuration with empty tag config updated
+     */
+    public XMLParserConfiguration withCloseEmptyTag(boolean closeEmptyTag){
+        XMLParserConfiguration clonedConfiguration = this.clone();
+        clonedConfiguration.closeEmptyTag = closeEmptyTag;
+        return clonedConfiguration;
+    }
+
+    public boolean isCloseEmptyTag() {
+        return this.closeEmptyTag;
+    }
 }

src/test/java/org/json/junit/XMLConfigurationTest.java

@@ -4,11 +4,6 @@
 Public Domain.
 */
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
-
 import java.io.File;
 import java.io.FileReader;
 import java.io.FileWriter;
@@ -27,6 +22,8 @@
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
 
+import static org.junit.Assert.*;
+
 
 /**
  * Tests for JSON-Java XML.java with XMLParserConfiguration.java
@@ -557,6 +554,37 @@ public void shouldHandleNullNodeValue()
         assertEquals(actualXML, resultXML);
     }
 
+    @Test
+    public void shouldHandleEmptyNodeValue()
+    {
+        JSONObject inputJSON = new JSONObject();
+        inputJSON.put("Emptyness", "");
+        String expectedXmlWithoutExplicitEndTag = "<Emptyness/>";
+        String expectedXmlWithExplicitEndTag = "<Emptyness></Emptyness>";
+        assertEquals(expectedXmlWithoutExplicitEndTag, XML.toString(inputJSON, null,
+                new XMLParserConfiguration().withCloseEmptyTag(false)));
+        assertEquals(expectedXmlWithExplicitEndTag, XML.toString(inputJSON, null,
+                new XMLParserConfiguration().withCloseEmptyTag(true)));
+    }
+
+    @Test
+    public void shouldKeepConfigurationIntactAndUpdateCloseEmptyTagChoice()
+    {
+        XMLParserConfiguration keepStrings = XMLParserConfiguration.KEEP_STRINGS;
+        XMLParserConfiguration keepStringsAndCloseEmptyTag = keepStrings.withCloseEmptyTag(true);
+        XMLParserConfiguration keepDigits = keepStringsAndCloseEmptyTag.withKeepStrings(false);
+        XMLParserConfiguration keepDigitsAndNoCloseEmptyTag = keepDigits.withCloseEmptyTag(false);
+        assertTrue(keepStrings.isKeepStrings());
+        assertFalse(keepStrings.isCloseEmptyTag());
+        assertTrue(keepStringsAndCloseEmptyTag.isKeepStrings());
+        assertTrue(keepStringsAndCloseEmptyTag.isCloseEmptyTag());
+        assertFalse(keepDigits.isKeepStrings());
+        assertTrue(keepDigits.isCloseEmptyTag());
+        assertFalse(keepDigitsAndNoCloseEmptyTag.isKeepStrings());
+        assertFalse(keepDigitsAndNoCloseEmptyTag.isCloseEmptyTag());
+
+    }
+
     /**
      * Investigate exactly how the "content" keyword works
      */

src/test/java/org/json/junit/XMLTest.java

@@ -1177,6 +1177,26 @@ public void testIndentComplicatedJsonObject(){
 
 
     }
+
+    @Test
+    public void shouldCreateExplicitEndTagWithEmptyValueWhenConfigured(){
+        String jsonString = "{outer:{innerOne:\"\", innerTwo:\"two\"}}";
+        JSONObject jsonObject = new JSONObject(jsonString);
+        String expectedXmlString = "<encloser><outer><innerOne></innerOne><innerTwo>two</innerTwo></outer></encloser>";
+        String xmlForm = XML.toString(jsonObject,"encloser", new XMLParserConfiguration().withCloseEmptyTag(true));
+        assertEquals(expectedXmlString, xmlForm);
+    }
+
+    @Test
+    public void shouldNotCreateExplicitEndTagWithEmptyValueWhenNotConfigured(){
+        String jsonString = "{outer:{innerOne:\"\", innerTwo:\"two\"}}";
+        JSONObject jsonObject = new JSONObject(jsonString);
+        String expectedXmlString = "<encloser><outer><innerOne/><innerTwo>two</innerTwo></outer></encloser>";
+        String xmlForm = XML.toString(jsonObject,"encloser", new XMLParserConfiguration().withCloseEmptyTag(false));
+        assertEquals(expectedXmlString, xmlForm);
+    }
+
+
     @Test
     public void testIndentSimpleJsonObject(){
         String str = "{    \"employee\": {  \n" +