serializing "format" in StringSchema#describePropertiesTo(), added FormatValidator#formatName() and implemented in builtin validators

Author: erosb

core/src/main/java/org/everit/json/schema/FormatValidator.java

@@ -80,4 +80,8 @@ static FormatValidator forFormat(final String formatName) {
      */
     Optional<String> validate(String subject);
 
+    default String formatName() {
+        return "unnamed-format";
+    }
+
 }

core/src/main/java/org/everit/json/schema/StringSchema.java

@@ -214,5 +214,8 @@ void describePropertiesTo(JSONPrinter writer) {
         writer.ifPresent("minLength", minLength);
         writer.ifPresent("maxLength", maxLength);
         writer.ifPresent("pattern", pattern);
+        if (formatValidator != null) {
+            writer.key("format").value(formatValidator.formatName());
+        }
     }
 }

core/src/main/java/org/everit/json/schema/internal/DateTimeFormatValidator.java

@@ -51,4 +51,8 @@ public Optional<String> validate(final String subject) {
         }
     }
 
+    @Override
+    public String formatName() {
+        return "date-time";
+    }
 }

core/src/main/java/org/everit/json/schema/internal/EmailFormatValidator.java

@@ -33,4 +33,8 @@ public Optional<String> validate(final String subject) {
         return Optional.of(String.format("[%s] is not a valid email address", subject));
     }
 
+    @Override
+    public String formatName() {
+        return "email";
+    }
 }

core/src/main/java/org/everit/json/schema/internal/HostnameFormatValidator.java

@@ -35,4 +35,8 @@ public Optional<String> validate(final String subject) {
         }
     }
 
+    @Override
+    public String formatName() {
+        return "hostname";
+    }
 }

core/src/main/java/org/everit/json/schema/internal/IPV4Validator.java

@@ -31,4 +31,8 @@ public Optional<String> validate(final String subject) {
         return checkIpAddress(subject, IPV4_LENGTH, "[%s] is not a valid ipv4 address");
     }
 
+    @Override
+    public String formatName() {
+        return "ipv4";
+    }
 }

core/src/main/java/org/everit/json/schema/internal/IPV6Validator.java

@@ -31,4 +31,8 @@ public Optional<String> validate(final String subject) {
         return checkIpAddress(subject, IPV6_LENGTH, "[%s] is not a valid ipv6 address");
     }
 
+    @Override
+    public String formatName() {
+        return "ipv6";
+    }
 }

core/src/main/java/org/everit/json/schema/internal/URIFormatValidator.java

@@ -36,4 +36,7 @@ public Optional<String> validate(final String subject) {
         }
     }
 
+    @Override public String formatName() {
+        return "uri";
+    }
 }

core/src/test/resources/org/everit/jsonvalidator/tostring/stringschema.json

@@ -2,5 +2,6 @@
   "type" : "string",
   "minLength": 0,
   "maxLength": 10,
-  "pattern": "a.b*c"
+  "pattern": "a.b*c",
+  "format": "date-time"
 }