More tweaks for #18

release-notes/VERSION-2.x

@@ -6,7 +6,7 @@ Project: jackson-databind
 
 2.10.0 (not yet released)
 
-#18: Make `ObjectNode` and `ArrayNode` serializable
+#18: Make `JsonNode` serializable
 #1675: Remove "impossible" `IOException` in `readTree()` and `readValue()` `ObjectMapper`
   methods which accept Strings
  (requested by matthew-pwnieexpress@github)

src/main/java/com/fasterxml/jackson/databind/node/ArrayNode.java

@@ -845,17 +845,6 @@ public int hashCode() {
         return _children.hashCode();
     }
 
-    /*
-    /**********************************************************
-    /* JDK Serialization support
-    /**********************************************************
-     */
-
-    // Simplest way is by using a helper
-    Object writeReplace() {
-        return NodeSerialization.from(this);
-    }
-
     /*
     /**********************************************************
     /* Internal methods (overridable)

src/main/java/com/fasterxml/jackson/databind/node/BaseJsonNode.java

@@ -14,10 +14,20 @@
  * The main addition here is that we declare that sub-classes must
  * implement {@link JsonSerializable}.
  * This simplifies object mapping aspects a bit, as no external serializers are needed.
+ *<p>
+ * Since 2.10, all implements have been {@link java.io.Serializable}.
  */
 public abstract class BaseJsonNode
     extends JsonNode
+    implements java.io.Serializable
 {
+    private static final long serialVersionUID = 1L;
+
+    // Simplest way is by using a helper
+    Object writeReplace() {
+        return NodeSerialization.from(this);
+    }
+
     protected BaseJsonNode() { }
 
     /*

src/main/java/com/fasterxml/jackson/databind/node/NodeSerialization.java

@@ -1,17 +1,23 @@
 package com.fasterxml.jackson.databind.node;
 
 import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
 
 /**
  * Helper value class only used during JDK serialization: contains JSON as `byte[]`
  *
  * @since 2.10
  */
-class NodeSerialization implements java.io.Serializable {
+class NodeSerialization implements java.io.Serializable,
+    java.io.Externalizable
+{
     private static final long serialVersionUID = 1L;
 
     public byte[] json;
 
+    public NodeSerialization() { }
+
     public NodeSerialization(byte[] b) { json = b; }
 
     protected Object readResolve() {
@@ -29,4 +35,17 @@ public static NodeSerialization from(Object o) {
             throw new IllegalArgumentException("Failed to JDK serialize `"+o.getClass().getSimpleName()+"` value: "+e.getMessage(), e);
         }
     }
+
+    @Override
+    public void writeExternal(ObjectOutput out) throws IOException {
+        out.writeInt(json.length);
+        out.write(json);
+    }
+
+    @Override
+    public void readExternal(ObjectInput in) throws IOException {
+        final int len = in.readInt();
+        json = new byte[len];
+        in.readFully(json, 0, len);
+    }
 }

src/main/java/com/fasterxml/jackson/databind/node/ObjectNode.java

@@ -875,17 +875,6 @@ public int hashCode()
         return _children.hashCode();
     }
 
-    /*
-    /**********************************************************
-    /* JDK Serialization support
-    /**********************************************************
-     */
-
-    // Simplest way is by using a helper
-    Object writeReplace() {
-        return NodeSerialization.from(this);
-    }
-
     /*
     /**********************************************************
     /* Internal methods (overridable)

src/test/java/com/fasterxml/jackson/databind/TestNodeJDKSerialization.java

@@ -25,9 +25,7 @@ public void testObjectNodeSerialization() throws Exception
         ObjectNode misc = root.with("misc");
         misc.put("value", 0.25);
 
-        byte[] ser = jdkSerialize(root);
-        JsonNode result = jdkDeserialize(ser);
-        assertEquals(root, result);
+        testNodeRoundtrip(root);
     }
 
     // [databind#18]: Allow JDK serialization of `ArrayNode`
@@ -39,17 +37,36 @@ public void testArrayNodeSerialization() throws Exception
         props.put("answer", 42);
         root.add(137);
 
-        byte[] ser = jdkSerialize(root);
-        JsonNode result = jdkDeserialize(ser);
-        assertEquals(root, result);
+        testNodeRoundtrip(root);
+    }
+
+    // and then also some scalar types
+    public void testScalarSerialization() throws Exception
+    {
+        testNodeRoundtrip(MAPPER.getNodeFactory().nullNode());
+
+        testNodeRoundtrip(MAPPER.getNodeFactory().textNode("Foobar"));
+
+        testNodeRoundtrip(MAPPER.getNodeFactory().booleanNode(true));
+        testNodeRoundtrip(MAPPER.getNodeFactory().booleanNode(false));
+
+        testNodeRoundtrip(MAPPER.getNodeFactory().numberNode(123));
+        testNodeRoundtrip(MAPPER.getNodeFactory().numberNode(-12345678901234L));
     }
 
     /*
     /**********************************************************
     /* Helper methods
     /**********************************************************
      */
-
+
+    protected void testNodeRoundtrip(JsonNode input) throws Exception
+    {
+        byte[] ser = jdkSerialize(input);
+        JsonNode result = jdkDeserialize(ser);
+        assertEquals(input, result);
+    }
+
     protected byte[] jdkSerialize(Object o) throws IOException
     {
         ByteArrayOutputStream bytes = new ByteArrayOutputStream(1000);