Start work on #549

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

@@ -178,6 +178,11 @@ public static int collectDefaults() {
 
     public final static SerializableString DEFAULT_ROOT_VALUE_SEPARATOR = DefaultPrettyPrinter.DEFAULT_ROOT_VALUE_SEPARATOR;
 
+    /**
+     * @since 2.10
+     */
+    public final static char DEFAULT_QUOTE_CHAR = '"';
+
     /*
     /**********************************************************
     /* Buffer, symbol table management
@@ -276,6 +281,13 @@ public static int collectDefaults() {
      */
     protected int _maximumNonEscapedChar;
 
+    /**
+     * Character used for quoting field names (if field name quoting has not
+     * been disabled with {@link JsonWriteFeature#QUOTE_FIELD_NAMES})
+     * and JSON String values.
+     */
+    protected final char _quoteChar;
+
     /*
     /**********************************************************
     /* Construction
@@ -294,7 +306,10 @@ public static int collectDefaults() {
      */
     public JsonFactory() { this((ObjectCodec) null); }
 
-    public JsonFactory(ObjectCodec oc) { _objectCodec = oc; }
+    public JsonFactory(ObjectCodec oc) {
+        _objectCodec = oc;
+        _quoteChar = DEFAULT_QUOTE_CHAR;
+    }
 
     /**
      * Constructor used when copy()ing a factory instance.
@@ -304,14 +319,19 @@ public static int collectDefaults() {
     protected JsonFactory(JsonFactory src, ObjectCodec codec)
     {
         _objectCodec = codec;
+
+        // General
         _factoryFeatures = src._factoryFeatures;
         _parserFeatures = src._parserFeatures;
         _generatorFeatures = src._generatorFeatures;
-        _characterEscapes = src._characterEscapes;
         _inputDecorator = src._inputDecorator;
         _outputDecorator = src._outputDecorator;
+
+        // JSON-specific
+        _characterEscapes = src._characterEscapes;
         _rootValueSeparator = src._rootValueSeparator;
         _maximumNonEscapedChar = src._maximumNonEscapedChar;
+        _quoteChar = src._quoteChar;
     }
 
     /**
@@ -320,10 +340,20 @@ protected JsonFactory(JsonFactory src, ObjectCodec codec)
      * @since 2.10
      */
     public JsonFactory(JsonFactoryBuilder b) {
-        this(b, false);
+        _objectCodec = null;
+
+        // General
+        _factoryFeatures = b._factoryFeatures;
+        _parserFeatures = b._streamReadFeatures;
+        _generatorFeatures = b._streamWriteFeatures;
+        _inputDecorator = b._inputDecorator;
+        _outputDecorator = b._outputDecorator;
+
+        // JSON-specific
         _characterEscapes = b._characterEscapes;
         _rootValueSeparator = b._rootValueSeparator;
         _maximumNonEscapedChar = b._maximumNonEscapedChar;
+        _quoteChar = b._quoteChar;
     }
 
     /**
@@ -336,15 +366,20 @@ public JsonFactory(JsonFactoryBuilder b) {
      */
     protected JsonFactory(TSFBuilder<?,?> b, boolean bogus) {
         _objectCodec = null;
+
         _factoryFeatures = b._factoryFeatures;
         _parserFeatures = b._streamReadFeatures;
         _generatorFeatures = b._streamWriteFeatures;
         _inputDecorator = b._inputDecorator;
         _outputDecorator = b._outputDecorator;
-        // NOTE: missing _maximumNonEscapedChar since that's only in JsonFactoryBuilder
+
+        // JSON-specific: need to assign even if not really used
+        _characterEscapes = null;
+        _rootValueSeparator = null;
         _maximumNonEscapedChar = 0;
+        _quoteChar = DEFAULT_QUOTE_CHAR;
     }
-    
+
     /**
      * Method that allows construction of differently configured factory, starting
      * with settings of this factory.
@@ -1698,7 +1733,7 @@ protected IOContext _createNonBlockingContext(Object srcRef) {
         return new IOContext(recycler, srcRef, false);
     }
 
-/*
+    /*
     /**********************************************************
     /* Internal helper methods
     /**********************************************************

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

@@ -9,6 +9,10 @@
  * {@link com.fasterxml.jackson.core.TSFBuilder}
  * implementation for constructing vanilla {@link JsonFactory}
  * instances for reading/writing JSON encoded content.
+ *<p>
+ * NOTE: as of Jackson 2.x, use of JSON-specific builder is bit cumbersome
+ * since {@link JsonFactory} serves dual duty of base class AND actual
+ * implementation for JSON backend. This will be fixed in Jackson 3.0.
  *
  * @since 2.10
  */
@@ -20,6 +24,13 @@ public class JsonFactoryBuilder extends TSFBuilder<JsonFactory, JsonFactoryBuild
 
     protected int _maximumNonEscapedChar;
 
+    /**
+     * Character used for quoting field names (if field name quoting has not
+     * been disabled with {@link JsonWriteFeature#QUOTE_FIELD_NAMES})
+     * and JSON String values.
+     */
+    protected char _quoteChar = JsonFactory.DEFAULT_QUOTE_CHAR;
+
     public JsonFactoryBuilder() {
         super();
         _rootValueSeparator = JsonFactory.DEFAULT_ROOT_VALUE_SEPARATOR;
@@ -160,8 +171,9 @@ public JsonFactoryBuilder rootValueSeparator(SerializableString sep) {
      * Default setting is "disabled", specified by passing value of {@code 0} (or
      * negative numbers).
      *<p>
-     * NOTE! Lowest value (aside from marker 0) is 127: for ASCII range, other checks apply
-     * and this threshold is ignored.
+     * NOTE! Lowest legal value (aside from marker 0) is 127: for ASCII range, other checks apply
+     * and this threshold is ignored. If value between [1, 126] is specified, 127 will be
+     * used instead.
      * 
      * @param maxNonEscaped Highest character code that is NOT automatically escaped; if
      *    positive value above 0, or 0 to indicate that no automatic escaping is applied
@@ -174,13 +186,31 @@ public JsonFactoryBuilder highestNonEscapedChar(int maxNonEscaped) {
         return this;
     }
 
+    /**
+     * Method that allows specifying an alternate
+     * character used for quoting field names (if field name quoting has not
+     * been disabled with {@link JsonWriteFeature#QUOTE_FIELD_NAMES})
+     * and JSON String values.
+     *<p>
+     * Default value is double-quote ({@code "}); typical alternative is
+     * single-quote/apostrophe ({@code '}).
+     *
+     * @param ch Character to use for quoting field names and JSON String values.
+     */
+    public JsonFactoryBuilder quoteChar(char ch) {
+        _quoteChar = ch;
+        return this;
+    }
+
     // // // Accessors for JSON-specific settings
 
     public CharacterEscapes characterEscapes() { return _characterEscapes; }
     public SerializableString rootValueSeparator() { return _rootValueSeparator; }
 
     public int highestNonEscapedChar() { return _maximumNonEscapedChar; }
 
+    public char quoteChar() { return _quoteChar; }
+
     @Override
     public JsonFactory build() {
         // 28-Dec-2017, tatu: No special settings beyond base class ones, so:

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

@@ -53,7 +53,7 @@ public class UTF8JsonGenerator
      * @since 2.8
      */
     protected byte _quoteChar = '"'; // TODO: make configurable
-    
+
     /*
     /**********************************************************
     /* Output buffering