Allow custom JsonNode implementations (#3701)

FasterXML · Dec 20, 2022 · 68ef028 · 68ef028
1 parent dd733c4
commit 68ef028
Show file tree

Hide file tree

Showing 2 changed files with 267 additions and 1 deletion.
diff --git a/src/main/java/com/fasterxml/jackson/databind/node/NodeCursor.java b/src/main/java/com/fasterxml/jackson/databind/node/NodeCursor.java
@@ -195,7 +195,7 @@ protected final static class ObjectCursor
         public ObjectCursor(JsonNode n, NodeCursor p)
         {
             super(JsonStreamContext.TYPE_OBJECT, p);
-            _contents = ((ObjectNode) n).fields();
+            _contents = n.fields();
             _needEntry = true;
         }
 

diff --git a/src/test/java/com/fasterxml/jackson/databind/ObjectReaderTest.java b/src/test/java/com/fasterxml/jackson/databind/ObjectReaderTest.java
@@ -3,6 +3,7 @@
 import java.io.IOException;
 import java.io.StringWriter;
 import java.util.*;
+import java.util.Map.Entry;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
@@ -16,8 +17,11 @@
 import com.fasterxml.jackson.databind.exc.InvalidDefinitionException;
 import com.fasterxml.jackson.databind.exc.MismatchedInputException;
 import com.fasterxml.jackson.databind.json.JsonMapper;
+import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
 import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.BaseJsonNode;
 import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import com.fasterxml.jackson.databind.node.JsonNodeType;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 
 public class ObjectReaderTest extends BaseMapTest
@@ -532,4 +536,266 @@ private A(@JsonProperty("knownField") String knownField) {
             this.knownField = knownField;
         }
     }
+
+    // [databind#3699]: custom object node classes
+    public void testCustomObjectNode() throws Exception
+    {
+        ObjectNode defaultNode = (ObjectNode) MAPPER.readTree("{\"x\": 1, \"y\": 2}");
+        CustomObjectNode customObjectNode = new CustomObjectNode(defaultNode);
+        Point point = MAPPER.readerFor(Point.class).readValue(customObjectNode);
+        assertEquals(1, point.x);
+        assertEquals(2, point.y);
+    }
+
+    // [databind#3699]: custom array node classes
+    public void testCustomArrayNode() throws Exception
+    {
+        ArrayNode defaultNode = (ArrayNode) MAPPER.readTree("[{\"x\": 1, \"y\": 2}]");
+        CustomArrayNode customArrayNode = new CustomArrayNode(defaultNode);
+        Point[] points = MAPPER.readerFor(Point[].class).readValue(customArrayNode);
+        Point point = points[0];
+        assertEquals(1, point.x);
+        assertEquals(2, point.y);
+    }
+
+    static class CustomObjectNode extends BaseJsonNode
+    {
+        private final ObjectNode _delegate;
+
+        CustomObjectNode(ObjectNode delegate) {
+            this._delegate = delegate;
+        }
+
+        @Override
+        public boolean isObject() {
+            return true;
+        }
+
+        @Override
+        public int size() {
+            return _delegate.size();
+        }
+
+        @Override
+        public Iterator<Entry<String, JsonNode>> fields() {
+            return _delegate.fields();
+        }
+
+        @Override
+        public Iterator<JsonNode> elements() {
+            return Collections.emptyIterator();
+        }
+
+        @Override
+        public JsonToken asToken() {
+            return JsonToken.START_OBJECT;
+        }
+
+        @Override
+        public void serialize(JsonGenerator g, SerializerProvider ctxt) {
+            // ignore, will not be called
+        }
+
+        @Override
+        public void serializeWithType(JsonGenerator g, SerializerProvider ctxt, TypeSerializer typeSer) {
+            // ignore, will not be called
+        }
+
+        @Override
+        @SuppressWarnings("unchecked")
+        public <T extends JsonNode> T deepCopy() {
+            return (T) new CustomObjectNode(_delegate);
+        }
+
+        @Override
+        public JsonNode get(int index) {
+            return null;
+        }
+
+        @Override
+        public JsonNode path(String fieldName) {
+            return null;
+        }
+
+        @Override
+        public JsonNode path(int index) {
+            return null;
+        }
+
+        @Override
+        protected JsonNode _at(JsonPointer ptr) {
+            return null;
+        }
+
+        @Override
+        public JsonNodeType getNodeType() {
+            return JsonNodeType.OBJECT;
+        }
+
+        @Override
+        public String asText() {
+            return "";
+        }
+
+        @Override
+        public JsonNode findValue(String fieldName) {
+            return null;
+        }
+
+        @Override
+        public JsonNode findParent(String fieldName) {
+            return null;
+        }
+
+        @Override
+        public List<JsonNode> findValues(String fieldName, List<JsonNode> foundSoFar) {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public List<String> findValuesAsText(String fieldName, List<String> foundSoFar) {
+            return foundSoFar;
+        }
+
+        @Override
+        public List<JsonNode> findParents(String fieldName, List<JsonNode> foundSoFar) {
+            return foundSoFar;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (o == this) {
+                return true;
+            }
+            if (!(o instanceof CustomObjectNode)) {
+                return false;
+            }
+            CustomObjectNode other = (CustomObjectNode) o;
+            return this._delegate.equals(other._delegate);
+        }
+
+        @Override
+        public int hashCode() {
+            return _delegate.hashCode();
+        }
+
+    }
+
+    static class CustomArrayNode extends BaseJsonNode
+    {
+        private final ArrayNode _delegate;
+
+        CustomArrayNode(ArrayNode delegate) {
+            this._delegate = delegate;
+        }
+
+        @Override
+        public boolean isArray() {
+            return true;
+        }
+
+        @Override
+        public int size() {
+            return _delegate.size();
+        }
+
+        @Override
+        public Iterator<JsonNode> elements() {
+            return _delegate.elements();
+        }
+
+        @Override
+        public JsonToken asToken() {
+            return JsonToken.START_ARRAY;
+        }
+
+        @Override
+        public void serialize(JsonGenerator g, SerializerProvider ctxt) {
+            // ignore, will not be called
+        }
+
+        @Override
+        public void serializeWithType(JsonGenerator g, SerializerProvider ctxt, TypeSerializer typeSer) {
+            // ignore, will not be called
+        }
+
+        @Override
+        @SuppressWarnings("unchecked")
+        public <T extends JsonNode> T deepCopy() {
+            return (T) new CustomArrayNode(_delegate);
+        }
+
+        @Override
+        public JsonNode get(int index) {
+            return _delegate.get(index);
+        }
+
+        @Override
+        public JsonNode path(String fieldName) {
+            return null;
+        }
+
+        @Override
+        public JsonNode path(int index) {
+            return _delegate.path(index);
+        }
+
+        @Override
+        protected JsonNode _at(JsonPointer ptr) {
+            return null;
+        }
+
+        @Override
+        public JsonNodeType getNodeType() {
+            return JsonNodeType.ARRAY;
+        }
+
+        @Override
+        public String asText() {
+            return "";
+        }
+
+        @Override
+        public JsonNode findValue(String fieldName) {
+            return null;
+        }
+
+        @Override
+        public JsonNode findParent(String fieldName) {
+            return null;
+        }
+
+        @Override
+        public List<JsonNode> findValues(String fieldName, List<JsonNode> foundSoFar) {
+            return foundSoFar;
+        }
+
+        @Override
+        public List<String> findValuesAsText(String fieldName, List<String> foundSoFar) {
+            return foundSoFar;
+        }
+
+        @Override
+        public List<JsonNode> findParents(String fieldName, List<JsonNode> foundSoFar) {
+            return foundSoFar;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (o == this) {
+                return true;
+            }
+            if (!(o instanceof CustomArrayNode)) {
+                return false;
+            }
+            CustomArrayNode other = (CustomArrayNode) o;
+            return this._delegate.equals(other._delegate);
+        }
+
+        @Override
+        public int hashCode() {
+            return _delegate.hashCode();
+        }
+
+    }
 }