fixes #4 unicode length

Author: stevehu

src/main/java/com/networknt/schema/MaxLengthValidator.java

@@ -48,11 +48,9 @@ public Set<ValidationMessage> validate(JsonNode node, JsonNode rootNode, String
             // ignore no-string typs
             return errors;
         }
-
-        if (node.textValue().length() > maxLength) {
+        if (node.textValue().codePointCount(0, node.textValue().length()) > maxLength) {
             errors.add(buildValidationMessage(at, "" + maxLength));
         }
-
         return errors;
     }
 

src/main/java/com/networknt/schema/MinLengthValidator.java

@@ -49,10 +49,9 @@ public Set<ValidationMessage> validate(JsonNode node, JsonNode rootNode, String
             return errors;
         }
 
-        if (node.textValue().length() < minLength) {
+        if (node.textValue().codePointCount(0, node.textValue().length()) < minLength) {
             errors.add(buildValidationMessage(at, "" + minLength));
         }
-
         return errors;
     }
 

src/test/resources/tests/maxLength.json

@@ -22,6 +22,11 @@
                 "description": "ignores non-strings",
                 "data": 100,
                 "valid": true
+            },
+            {
+                "description": "two supplementary Unicode code points is long enough",
+                "data": "\uD83D\uDCA9\uD83D\uDCA9",
+                "valid": true
             }
         ]
     }

src/test/resources/tests/minLength.json

@@ -22,6 +22,11 @@
                 "description": "ignores non-strings",
                 "data": 1,
                 "valid": true
+            },
+            {
+                "description": "one supplementary Unicode code point is not long enough",
+                "data": "\uD83D\uDCA9",
+                "valid": false
             }
         ]
     }