fix FasterXML#116 "null" Strings when Feature.MINIMIZE_QUOTES is active

Signed-off-by: Stefan stefanleh@users.noreply.github.com
stefanleh · Jan 25, 2019 · 6106dc6 · 6106dc6
1 parent 00c3d1d
commit 6106dc6
Showing 1 changed file with 21 additions and 4 deletions.
diff --git a/yaml/src/main/java/com/fasterxml/jackson/dataformat/yaml/YAMLGenerator.java b/yaml/src/main/java/com/fasterxml/jackson/dataformat/yaml/YAMLGenerator.java
@@ -21,6 +21,14 @@
 
 public class YAMLGenerator extends GeneratorBase
 {
+	/**
+	 * Static string values which should not be instantiated every time.
+	 */
+	private final static String TRUE_VALUE = "true";
+    private final static String FALSE_VALUE = "false";
+    private final static String NULL_UP_VALUE = "NULL";
+    private final static String NULL_LW_VALUE = "null";
+
     /**
      * Enumeration that defines all togglable features for YAML generators
      */
@@ -523,8 +531,12 @@ public void writeString(String text) throws IOException,JsonGenerationException
         }
         _verifyValueWrite("write String value");
         DumperOptions.ScalarStyle style = STYLE_QUOTED;
-        if (Feature.MINIMIZE_QUOTES.enabledIn(_formatWriteFeatures) && !isBooleanContent(text)) {
-          // If this string could be interpreted as a number, it must be quoted.
+
+        if (Feature.MINIMIZE_QUOTES.enabledIn(_formatWriteFeatures) 
+        		&& !isBooleanContent(text) 
+        		&& !isStringNullContent(text)) {
+
+        	// If this string could be interpreted as a number, it must be quoted.
             if (Feature.ALWAYS_QUOTE_NUMBERS_AS_STRINGS.enabledIn(_formatWriteFeatures)
                     && PLAIN_NUMBER_P.matcher(text).matches()) {
                 style = STYLE_QUOTED;
@@ -533,14 +545,19 @@ public void writeString(String text) throws IOException,JsonGenerationException
             } else {
                 style = STYLE_PLAIN;
             }
+
         } else if (Feature.LITERAL_BLOCK_STYLE.enabledIn(_formatWriteFeatures) && text.indexOf('\n') >= 0) {
             style = STYLE_LITERAL;
         }
         _writeScalar(text, "string", style);
     }
 
-    private boolean isBooleanContent(String text) {
-        return text.equals("true") || text.equals("false");
+	private boolean isBooleanContent(String text) {
+        return TRUE_VALUE.equals(text) || FALSE_VALUE.equals(text);
+    }
+
+	private boolean isStringNullContent(String text) {
+        return NULL_LW_VALUE.equals(text) || NULL_UP_VALUE.equals(text);
     }
 
     @Override