Fix #257

release-notes/VERSION

@@ -19,6 +19,7 @@ JSON library.
 #253: Add `JsonGenerator. writeEmbeddedObject()` to allow writes of opaque native types
  (suggested by Gregoire C)
 #255: Relax ownership checks for buffers not to require increase in size
+#257: Add `writeStartObject(Object pojo)` to streamline assignment of current value
 
 2.7.2 (26-Feb-2016)
 

src/main/java/com/fasterxml/jackson/core/JsonGenerator.java

@@ -755,6 +755,26 @@ public void writeStartArray(int size) throws IOException {
      */
     public abstract void writeStartObject() throws IOException;
 
+    /**
+     * Method for writing starting marker of a JSON Object value
+     * (character '{'; plus possible white space decoration
+     * if pretty-printing is enabled), to represent Java given
+     * as the argument. Argument is offered as metadata, but more
+     * importantly it should be assigned as the "current value"
+     * for the Object content that gets constructed and initialized.
+     *<p>
+     * Object values can be written in any context where values
+     * are allowed: meaning everywhere except for when
+     * a field name is expected.
+     *
+     * @since 2.8.
+     */
+    public void writeStartObject(Object forValue) throws IOException
+    {
+        writeStartObject();
+        setCurrentValue(forValue);
+    }
+
     /**
      * Method for writing closing marker of a JSON Object value
      * (character '}'; plus possible white space decoration

src/main/java/com/fasterxml/jackson/core/base/GeneratorBase.java

@@ -266,6 +266,16 @@ protected void _checkStdFeatureChanges(int newFeatureFlags, int changedFeatures)
     //public void writeStartObject() throws IOException
     //public void writeEndObject() throws IOException
 
+    @Override // since 2.8
+    public void writeStartObject(Object forValue) throws IOException
+    {
+        writeStartObject();
+        if ((_writeContext != null) && (forValue != null)) {
+            _writeContext.setCurrentValue(forValue);
+        }
+        setCurrentValue(forValue);
+    }
+
     /*
     /**********************************************************
     /* Public API, write methods, textual

src/main/java/com/fasterxml/jackson/core/json/UTF8JsonGenerator.java

@@ -309,6 +309,25 @@ public final void writeStartObject() throws IOException
         }
     }
 
+    @Override // since 2.8
+    public void writeStartObject(Object forValue) throws IOException
+    {
+        _verifyValueWrite("start an object");
+        JsonWriteContext ctxt = _writeContext.createChildObjectContext();
+        _writeContext = ctxt;
+        if (forValue != null) {
+            ctxt.setCurrentValue(forValue);
+        }
+        if (_cfgPrettyPrinter != null) {
+            _cfgPrettyPrinter.writeStartObject(this);
+        } else {
+            if (_outputTail >= _outputEnd) {
+                _flushBuffer();
+            }
+            _outputBuffer[_outputTail++] = '{';
+        }
+    }
+
     @Override
     public final void writeEndObject() throws IOException
     {

src/main/java/com/fasterxml/jackson/core/json/WriterBasedJsonGenerator.java

@@ -195,7 +195,7 @@ protected void _writeFieldName(SerializableString name, boolean commaBefore) thr
      */
 
     @Override
-    public void writeStartArray() throws IOException, JsonGenerationException
+    public void writeStartArray() throws IOException
     {
         _verifyValueWrite("start an array");
         _writeContext = _writeContext.createChildArrayContext();
@@ -210,7 +210,7 @@ public void writeStartArray() throws IOException, JsonGenerationException
     }
 
     @Override
-    public void writeEndArray() throws IOException, JsonGenerationException
+    public void writeEndArray() throws IOException
     {
         if (!_writeContext.inArray()) {
             _reportError("Current context not an ARRAY but "+_writeContext.getTypeDesc());
@@ -226,8 +226,27 @@ public void writeEndArray() throws IOException, JsonGenerationException
         _writeContext = _writeContext.clearAndGetParent();
     }
 
+    @Override // since 2.8
+    public void writeStartObject(Object forValue) throws IOException
+    {
+        _verifyValueWrite("start an object");
+        JsonWriteContext ctxt = _writeContext.createChildObjectContext();
+        _writeContext = ctxt;
+        if (forValue != null) {
+            ctxt.setCurrentValue(forValue);
+        }
+        if (_cfgPrettyPrinter != null) {
+            _cfgPrettyPrinter.writeStartObject(this);
+        } else {
+            if (_outputTail >= _outputEnd) {
+                _flushBuffer();
+            }
+            _outputBuffer[_outputTail++] = '{';
+        }
+    }
+
     @Override
-    public void writeStartObject() throws IOException, JsonGenerationException
+    public void writeStartObject() throws IOException
     {
         _verifyValueWrite("start an object");
         _writeContext = _writeContext.createChildObjectContext();
@@ -242,7 +261,7 @@ public void writeStartObject() throws IOException, JsonGenerationException
     }
 
     @Override
-    public void writeEndObject() throws IOException, JsonGenerationException
+    public void writeEndObject() throws IOException
     {
         if (!_writeContext.inObject()) {
             _reportError("Current context not an object but "+_writeContext.getTypeDesc());

src/main/java/com/fasterxml/jackson/core/util/JsonGeneratorDelegate.java

@@ -200,6 +200,9 @@ public JsonGenerator setPrettyPrinter(PrettyPrinter pp) {
 
     @Override
     public void writeStartObject() throws IOException { delegate.writeStartObject(); }
+
+    @Override
+    public void writeStartObject(Object forValue) throws IOException { delegate.writeStartObject(forValue); }
 
     @Override
     public void writeEndObject() throws IOException { delegate.writeEndObject(); }