Fix #441

FasterXML · Jul 6, 2021 · 71c17d8 · 71c17d8
1 parent 97fe9eb
commit 71c17d8
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diff --git a/release-notes/VERSION-2.x b/release-notes/VERSION-2.x
@@ -6,6 +6,8 @@ Project: jackson-dataformat-xml
 
 2.13.0 (not yet released)
 
+#441: Add `ToXmlGenerator.Feature.UNWRAP_ROOT_OBJECT_NODE` (to avoid
+  root `ObjectNode` wrapper element)
 #442: Missing `START_OBJECT` token in complex element starting with text
  (reported by richardsonwk@github)
 #462: Remove `jackson-module-jaxb-annotations` runtime dependency (leave

diff --git a/src/main/java/com/fasterxml/jackson/dataformat/xml/ser/ToXmlGenerator.java b/src/main/java/com/fasterxml/jackson/dataformat/xml/ser/ToXmlGenerator.java
@@ -77,8 +77,8 @@ public enum Feature implements FormatFeature
 
         /**
          * Feature that determines writing of root values of type {@code ObjectNode}
-         * ({@code JsonNode} that represents Object content values), regarding
-         * XML output.
+         * ({@code JsonNode} subtype that represents Object content values),
+         * regarding XML output.
          * If enabled and {@code ObjectNode} has exactly one entry (key/value pair),
          * then key of that entry is used as the root element name (and value
          * is written as contents. Otherwise (if feature disabled, or if root

diff --git a/src/main/java/com/fasterxml/jackson/dataformat/xml/ser/XmlSerializerProvider.java b/src/main/java/com/fasterxml/jackson/dataformat/xml/ser/XmlSerializerProvider.java
@@ -1,20 +1,20 @@
 package com.fasterxml.jackson.dataformat.xml.ser;
 
 import java.io.IOException;
+import java.util.Map;
 
 import javax.xml.namespace.QName;
 import javax.xml.stream.XMLStreamException;
 
 import com.fasterxml.jackson.core.*;
-import com.fasterxml.jackson.databind.JavaType;
-import com.fasterxml.jackson.databind.JsonMappingException;
-import com.fasterxml.jackson.databind.JsonSerializer;
-import com.fasterxml.jackson.databind.PropertyName;
-import com.fasterxml.jackson.databind.SerializationConfig;
+
+import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.fasterxml.jackson.databind.ser.SerializerFactory;
 import com.fasterxml.jackson.databind.ser.DefaultSerializerProvider;
 import com.fasterxml.jackson.databind.util.TokenBuffer;
+
 import com.fasterxml.jackson.dataformat.xml.util.StaxUtil;
 import com.fasterxml.jackson.dataformat.xml.util.TypeUtil;
 import com.fasterxml.jackson.dataformat.xml.util.XmlRootNameLookup;
@@ -86,6 +86,12 @@ public void serializeValue(JsonGenerator gen, Object value) throws IOException
         if (xgen == null) { // called by convertValue()
             asArray = false;
         } else {
+            // [dataformat-xml#441]: allow ObjectNode unwrapping
+            if (_shouldUnwrapObjectNode(xgen, value)) {
+                _serializeUnwrappedObjectNode(xgen, value,
+                        findTypedValueSerializer(cls, true, null));
+                return;
+            }
             QName rootName = _rootNameFromConfig();
             if (rootName == null) {
                 rootName = _rootNameLookup.findRootName(cls, _config);
@@ -116,7 +122,7 @@ public void serializeValue(JsonGenerator gen, Object value, JavaType rootType) t
     {
         serializeValue(gen, value, rootType, null);
     }
-    
+
     // @since 2.1
     @SuppressWarnings("resource")
     @Override
@@ -137,6 +143,11 @@ public void serializeValue(JsonGenerator gen, Object value, JavaType rootType,
         if (xgen == null) { // called by convertValue()
             asArray = false;
         } else {
+            // [dataformat-xml#441]: allow ObjectNode unwrapping
+            if (_shouldUnwrapObjectNode(xgen, value)) {
+                _serializeUnwrappedObjectNode(xgen, value, ser);
+                return;
+            }
             QName rootName = _rootNameFromConfig();
             if (rootName == null) {
                 rootName = _rootNameLookup.findRootName(rootType, _config);
@@ -211,7 +222,7 @@ public void serializePolymorphic(JsonGenerator gen, Object value, JavaType rootT
             gen.writeEndObject();
         }
     }
-    
+
     protected void _serializeXmlNull(JsonGenerator gen) throws IOException
     {
         // 14-Nov-2016, tatu: As per [dataformat-xml#213], we may have explicitly
@@ -245,10 +256,9 @@ protected void _initWithRootName(ToXmlGenerator xgen, QName rootName) throws IOE
         }
         xgen.initGenerator();
         String ns = rootName.getNamespaceURI();
-        /* [dataformat-xml#26] If we just try writing root element with namespace,
-         * we will get an explicit prefix. But we'd rather use the default
-         * namespace, so let's try to force that.
-         */
+        // [dataformat-xml#26] If we just try writing root element with namespace,
+        // we will get an explicit prefix. But we'd rather use the default
+        // namespace, so let's try to force that.
         if (ns != null && ns.length() > 0) {
             try {
                 xgen.getStaxWriter().setDefaultNamespace(ns);
@@ -271,6 +281,35 @@ protected QName _rootNameFromConfig()
         return new QName(ns, name.getSimpleName());
     }
 
+    // @since 2.13
+    protected boolean _shouldUnwrapObjectNode(ToXmlGenerator xgen, Object value)
+    {
+        return xgen.isEnabled(ToXmlGenerator.Feature.UNWRAP_ROOT_OBJECT_NODE)
+                && (value instanceof ObjectNode)
+                && (((ObjectNode) value).size() == 1);
+    }
+
+    // @since 2.13
+    protected void _serializeUnwrappedObjectNode(ToXmlGenerator xgen, Object value,
+            JsonSerializer<Object> ser) throws IOException
+    {
+        ObjectNode root = (ObjectNode) value;
+        Map.Entry<String, JsonNode> entry = root.fields().next();
+        final JsonNode newRoot = entry.getValue();
+
+        // No namespace associated with JsonNode:
+        _initWithRootName(xgen, new QName(entry.getKey()));
+        if (ser == null) {
+            ser = findTypedValueSerializer(newRoot.getClass(), true, null);
+        }
+        // From super-class implementation
+        try {
+            ser.serialize(newRoot, xgen, this);
+        } catch (Exception e) { // but others do need to be, to get path etc
+            throw _wrapAsIOE(xgen, e);
+        }
+    }
+
     protected ToXmlGenerator _asXmlGenerator(JsonGenerator gen)
         throws JsonMappingException
     {

diff --git a/.../xml/failing/JsonNodeBasicSer441Test.java → ...xml/node/JsonNodeSerUnwrapped441Test.java b/.../xml/failing/JsonNodeBasicSer441Test.java → ...xml/node/JsonNodeSerUnwrapped441Test.java
@@ -1,4 +1,4 @@
-package com.fasterxml.jackson.dataformat.xml.failing;
+package com.fasterxml.jackson.dataformat.xml.node;
 
 import com.fasterxml.jackson.annotation.JsonUnwrapped;
 
@@ -10,9 +10,9 @@
 import com.fasterxml.jackson.dataformat.xml.XmlTestBase;
 import com.fasterxml.jackson.dataformat.xml.ser.ToXmlGenerator;
 
-// for [dataformat-xml#441]
-public class JsonNodeBasicSer441Test extends XmlTestBase
+public class JsonNodeSerUnwrapped441Test extends XmlTestBase
 {
+    // [dataformat-xml#441]
     static class Stuff441 {
         @JsonUnwrapped
         public ObjectNode node;
@@ -27,26 +27,42 @@ static class Stuff441 {
     private final ObjectWriter XML_WRITER_UNWRAP = XML_MAPPER.writer()
             .with(ToXmlGenerator.Feature.UNWRAP_ROOT_OBJECT_NODE);
 
-    public void testSimpleNode() throws Exception
+    // [dataformat-xml#441]: before changes, work-around should be fine
+    public void testOlderWorkaround() throws Exception
     {
         ObjectNode xml = XML_MAPPER.createObjectNode();
-        ObjectNode root = xml.putObject("root");
-        root.put("id", 13);
-        root.put("enabled", true);
+        ObjectNode child = xml.putObject("root");
+        child.put("id", 11);
+        child.put("enabled", false);
+
+        // Had to manually unwrap, set root name...
+        assertEquals("<root><id>11</id><enabled>false</enabled></root>",
+                XML_WRITER_WRAP.withRootName("root")
+                    .writeValueAsString(child));
+    }
+
+    // [dataformat-xml#441]
+    public void testSimpleNode() throws Exception
+    {
+        ObjectNode root = XML_MAPPER.createObjectNode();
+        ObjectNode child = root.putObject("root");
+        child.put("id", 13);
+        child.put("enabled", true);
 
         final String INNER = "<root><id>13</id><enabled>true</enabled></root>";
 
         assertEquals("<ObjectNode>"+INNER+"</ObjectNode>",
-                XML_WRITER_WRAP.writeValueAsString(xml));
+                XML_WRITER_WRAP.writeValueAsString(root));
         assertEquals(INNER,
-                XML_WRITER_UNWRAP.writeValueAsString(xml));
+                XML_WRITER_UNWRAP.writeValueAsString(root));
     }
 
+    // [dataformat-xml#441]
     public void testArrayInObjectNode() throws Exception
     {
-        ObjectNode xml = XML_MAPPER.createObjectNode();
-        ObjectNode root = xml.putObject("root");
-        ArrayNode arr = root.putArray("array");
+        ObjectNode root = XML_MAPPER.createObjectNode();
+        ObjectNode child = root.putObject("root");
+        ArrayNode arr = child.putArray("array");
         arr.add("first");
         ObjectNode second = arr.addObject();
         second.put("value", 137);
@@ -55,9 +71,9 @@ public void testArrayInObjectNode() throws Exception
 
 //System.err.println("XML/array: "+XML_MAPPER.writeValueAsString(xml));
         assertEquals("<ObjectNode>"+INNER+"</ObjectNode>",
-                XML_WRITER_WRAP.writeValueAsString(xml));
+                XML_WRITER_WRAP.writeValueAsString(root));
         assertEquals(INNER,
-                XML_WRITER_UNWRAP.writeValueAsString(xml));
+                XML_WRITER_UNWRAP.writeValueAsString(root));
     }
 
     // 03-Jul-2021, tatu: Would be great to further support "unwrapping" of