Refactor validation message generation (#910)

* Add strategy for resolving locale specific messages

* Support priority list

* Use per execution locale

* Support custom message per property

Author: justin-tay

doc/cust-msg.md

@@ -6,7 +6,7 @@ The json schema itself has a place for the customised message.
 ## Examples
 ### Example 1 :
 The custom message can be provided outside properties for each type, as shown in the schema below.
-````json
+```json
 {
   "type": "object",
   "properties": {
@@ -24,10 +24,10 @@ The custom message can be provided outside properties for each type, as shown in
     "type" : "Invalid type"
   }
 }
-````
+```
 ### Example 2 :
 To keep custom messages distinct for each type, one can even give them in each property.
-````json
+```json
 {
   "type": "object",
   "properties": {
@@ -47,14 +47,62 @@ To keep custom messages distinct for each type, one can even give them in each p
     }
   }
 }
-````
+```
+### Example 3 :
+For the keywords `required` and `dependencies`, different messages can be specified for different properties.
+
+```json
+{
+  "type": "object",
+  "properties": {
+    "foo": {
+      "type": "number"
+    },
+    "bar": {
+      "type": "string"
+    }
+  },
+  "required": ["foo", "bar"],
+  "message": {
+    "type" : "should be an object",
+    "required": {
+      "foo" : "'foo' is required",
+      "bar" : "'bar' is required"
+    }
+  }
+}
+```
+### Example 4 :
+The message can use arguments but note that single quotes need to be escaped as `java.text.MessageFormat` will be used to format the message.
+
+```json
+{
+  "type": "object",
+  "properties": {
+    "foo": {
+      "type": "number"
+    },
+    "bar": {
+      "type": "string"
+    }
+  },
+  "required": ["foo", "bar"],
+  "message": {
+    "type" : "should be an object",
+    "required": {
+      "foo" : "{0}: ''foo'' is required",
+      "bar" : "{0}: ''bar'' is required"
+    }
+  }
+}
+```
 
 ## Format
-````json
+```json
 "message": {
     [validationType] : [customMessage]
   }
-````
+```
 Users can express custom message in the **'message'** field. 
 The **'validation type'** should be the key and the **'custom message'** should be the value.
 

doc/multiple-language.md

@@ -24,15 +24,47 @@ JsonSchema schema = factory.getSchema(source, config);
 ```
 
 Besides setting the locale and using the default resource bundle, you may also specify your own to cover any languages you
-choose without adapting the library's source, or to override default messages. In doing so you however you should ensure that
-your resource bundle covers all the keys defined by the default bundle. 
+choose without adapting the library's source, or to override default messages. In doing so you however you should ensure that your resource bundle covers all the keys defined by the default bundle. 
 
 ```
-// Set the configuration with a custom resource bundle (you can create this before each validation)
-ResourceBundle myBundle = ResourceBundle.getBundle("my-messages", myLocale);
+// Set the configuration with a custom message source
+MessageSource messageSource = new ResourceBundleMessageSource("my-messages");
 SchemaValidatorsConfig config = new SchemaValidatorsConfig();
-config.setResourceBundle(myBundle);
+config.setMessageSource(messageSource);
 JsonSchemaFactory factory = JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V201909);
 JsonSchema schema = factory.getSchema(source, config);
 ...
-```
+```
+
+It is possible to override specific keys from the default resource bundle. Note however that you will need to supply all the languages for that specific key as it will not fallback on the default resource bundle. For instance the jsv-messages-override resource bundle will take precedence when resolving the message key.
+
+```
+// Set the configuration with a custom message source
+MessageSource messageSource = new ResourceBundleMessageSource("jsv-messages-override", DefaultMessageSource.BUNDLE_BASE_NAME);
+SchemaValidatorsConfig config = new SchemaValidatorsConfig();
+config.setMessageSource(messageSource);
+JsonSchemaFactory factory = JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V201909);
+JsonSchema schema = factory.getSchema(source, config);
+...
+```
+
+The following approach can be used to determine the locale to use on a per user basis using a language tag priority list.
+
+```
+SchemaValidatorsConfig config = new SchemaValidatorsConfig();
+JsonSchemaFactory factory = JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V201909);
+JsonSchema schema = factory.getSchema(source, config);
+
+// Uses the fr locale for this user
+Locale locale = Locales.findSupported("it;q=0.9,fr;q=1.0");
+ExecutionContext executionContext = jsonSchema.createExecutionContext();
+executionContext.getExecutionConfig().setLocale(locale);
+Set<ValidationMessage> messages = jsonSchema.validate(executionContext, rootNode);
+
+// Uses the it locale for this user
+locale = Locales.findSupported("it;q=1.0,fr;q=0.9");
+executionContext = jsonSchema.createExecutionContext();
+executionContext.getExecutionConfig().setLocale(locale);
+messages = jsonSchema.validate(executionContext, rootNode);
+...
+```

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

@@ -97,7 +97,7 @@ public Set<ValidationMessage> validate(ExecutionContext executionContext, JsonNo
 
             if (!allowedProperties.contains(pname) && !handledByPatternProperties) {
                 if (!allowAdditionalProperties) {
-                    errors.add(buildValidationMessage(at, pname));
+                    errors.add(buildValidationMessage(null, at, executionContext.getExecutionConfig().getLocale(), pname));
                 } else {
                     if (additionalPropertiesSchema != null) {
                         ValidatorState state = (ValidatorState) collectorContext.get(ValidatorState.VALIDATOR_STATE_KEY);

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

@@ -77,7 +77,8 @@ public Set<ValidationMessage> validate(ExecutionContext executionContext, JsonNo
                         //If schema has type validator and node type doesn't match with schemaType then ignore it
                         //For union type, it is a must to call TypeValidator
                         if (typeValidator.getSchemaType() != JsonType.UNION && !typeValidator.equalsToSchemaType(node)) {
-                            allErrors.add(buildValidationMessage(at, typeValidator.getSchemaType().toString()));
+                            allErrors.add(buildValidationMessage(null, at,
+                                    executionContext.getExecutionConfig().getLocale(), typeValidator.getSchemaType().toString()));
                             continue;
                         }
                     }
@@ -106,7 +107,8 @@ public Set<ValidationMessage> validate(ExecutionContext executionContext, JsonNo
                         if (this.discriminatorContext.isDiscriminatorMatchFound()) {
                             if (!errors.isEmpty()) {
                                 allErrors.addAll(errors);
-                                allErrors.add(buildValidationMessage(at, DISCRIMINATOR_REMARK));
+                                allErrors.add(buildValidationMessage(null,
+                                        at, executionContext.getExecutionConfig().getLocale(), DISCRIMINATOR_REMARK));
                             } else {
                                 // Clear all errors.
                                 allErrors.clear();
@@ -133,7 +135,8 @@ public Set<ValidationMessage> validate(ExecutionContext executionContext, JsonNo
 
             if (this.validationContext.getConfig().isOpenAPI3StyleDiscriminators() && this.discriminatorContext.isActive()) {
                 final Set<ValidationMessage> errors = new HashSet<>();
-                errors.add(buildValidationMessage(at, "based on the provided discriminator. No alternative could be chosen based on the discriminator property"));
+                errors.add(buildValidationMessage(null, at,
+                        executionContext.getExecutionConfig().getLocale(), "based on the provided discriminator. No alternative could be chosen based on the discriminator property"));
                 return Collections.unmodifiableSet(errors);
             }
         } finally {

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

@@ -19,6 +19,8 @@
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.networknt.schema.ValidationContext.DiscriminatorContext;
+import com.networknt.schema.i18n.DefaultMessageSource;
+
 import org.slf4j.Logger;
 
 import java.net.URI;
@@ -47,7 +49,7 @@ public BaseJsonValidator(String schemaPath,
                              ValidatorTypeCode validatorType,
                              ValidationContext validationContext,
                              boolean suppressSubSchemaRetrieval) {
-        super(validationContext != null && validationContext.getConfig() != null && validationContext.getConfig().isFailFast(), validatorType, validatorType != null ? validatorType.getCustomMessage() : null, (validationContext != null && validationContext.getConfig() != null) ? validationContext.getConfig().getResourceBundle() : I18nSupport.DEFAULT_RESOURCE_BUNDLE, validatorType, parentSchema, schemaPath);
+        super(validationContext != null && validationContext.getConfig() != null && validationContext.getConfig().isFailFast(), validatorType, validatorType != null ? validatorType.getCustomMessage() : null, (validationContext != null && validationContext.getConfig() != null) ? validationContext.getConfig().getMessageSource() : DefaultMessageSource.getInstance(), validatorType, parentSchema, schemaPath);
         this.schemaNode = schemaNode;
         this.suppressSubSchemaRetrieval = suppressSubSchemaRetrieval;
         this.applyDefaultsStrategy = (validationContext != null && validationContext.getConfig() != null && validationContext.getConfig().getApplyDefaultsStrategy() != null) ? validationContext.getConfig().getApplyDefaultsStrategy() : ApplyDefaultsStrategy.EMPTY_APPLY_DEFAULTS_STRATEGY;

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

@@ -20,7 +20,6 @@
 import org.slf4j.LoggerFactory;
 
 import java.util.Collections;
-import java.util.LinkedHashSet;
 import java.util.Set;
 
 public class ConstValidator extends BaseJsonValidator implements JsonValidator {
@@ -35,14 +34,15 @@ public ConstValidator(String schemaPath, JsonNode schemaNode, JsonSchema parentS
     public Set<ValidationMessage> validate(ExecutionContext executionContext, JsonNode node, JsonNode rootNode, String at) {
         debug(logger, node, rootNode, at);
 
-        Set<ValidationMessage> errors = new LinkedHashSet<ValidationMessage>();
         if (schemaNode.isNumber() && node.isNumber()) {
             if (schemaNode.decimalValue().compareTo(node.decimalValue()) != 0) {
-                errors.add(buildValidationMessage(at, schemaNode.asText()));
+                return Collections.singleton(buildValidationMessage(null,
+                        at, executionContext.getExecutionConfig().getLocale(), schemaNode.asText()));
             }
         } else if (!schemaNode.equals(node)) {
-            errors.add(buildValidationMessage(at, schemaNode.asText()));
+            return Collections.singleton(
+                    buildValidationMessage(null, at, executionContext.getExecutionConfig().getLocale(), schemaNode.asText()));
         }
-        return Collections.unmodifiableSet(errors);
+        return Collections.emptySet();
     }
 }

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

@@ -23,6 +23,7 @@
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Locale;
 import java.util.Optional;
 import java.util.Set;
 
@@ -89,14 +90,16 @@ public Set<ValidationMessage> validate(ExecutionContext executionContext, JsonNo
                 if(isMinV201909) {
                     updateValidatorType(ValidatorTypeCode.MIN_CONTAINS);
                 }
-                return boundsViolated(isMinV201909 ? CONTAINS_MIN : ValidatorTypeCode.CONTAINS.getValue(), at, this.min);
+                return boundsViolated(isMinV201909 ? CONTAINS_MIN : ValidatorTypeCode.CONTAINS.getValue(),
+                        executionContext.getExecutionConfig().getLocale(), at, this.min);
             }
 
             if (actual > this.max) {
                 if(isMinV201909) {
                     updateValidatorType(ValidatorTypeCode.MAX_CONTAINS);
                 }
-                return boundsViolated(isMinV201909 ? CONTAINS_MAX : ValidatorTypeCode.CONTAINS.getValue(), at, this.max);
+                return boundsViolated(isMinV201909 ? CONTAINS_MAX : ValidatorTypeCode.CONTAINS.getValue(),
+                        executionContext.getExecutionConfig().getLocale(), at, this.max);
             }
         }
 
@@ -108,7 +111,7 @@ public void preloadJsonSchema() {
         Optional.ofNullable(this.schema).ifPresent(JsonSchema::initializeValidators);
     }
 
-    private Set<ValidationMessage> boundsViolated(String messageKey, String at, int bounds) {
-        return Collections.singleton(constructValidationMessage(messageKey, at, String.valueOf(bounds), this.schema.getSchemaNode().toString()));
+    private Set<ValidationMessage> boundsViolated(String messageKey, Locale locale, String at, int bounds) {
+        return Collections.singleton(buildValidationMessage(null, at, messageKey, locale, String.valueOf(bounds), this.schema.getSchemaNode().toString()));
     }
 }

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

@@ -62,7 +62,8 @@ public Set<ValidationMessage> validate(ExecutionContext executionContext, JsonNo
             if (deps != null && !deps.isEmpty()) {
                 for (String field : deps) {
                     if (node.get(field) == null) {
-                        errors.add(buildValidationMessage(at, propertyDeps.toString()));
+                        errors.add(buildValidationMessage(pname, at,
+                                executionContext.getExecutionConfig().getLocale(), propertyDeps.toString()));
                     }
                 }
             }

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

@@ -56,7 +56,8 @@ public Set<ValidationMessage> validate(ExecutionContext executionContext, JsonNo
             if (dependencies != null && !dependencies.isEmpty()) {
                 for (String field : dependencies) {
                     if (node.get(field) == null) {
-                        errors.add(buildValidationMessage(at, field, pname));
+                        errors.add(buildValidationMessage(pname, at, executionContext.getExecutionConfig().getLocale(),
+                                field, pname));
                     }
                 }
             }

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

@@ -24,7 +24,6 @@
 
 import java.util.Collections;
 import java.util.HashSet;
-import java.util.LinkedHashSet;
 import java.util.Set;
 
 public class EnumValidator extends BaseJsonValidator implements JsonValidator {
@@ -81,13 +80,12 @@ public EnumValidator(String schemaPath, JsonNode schemaNode, JsonSchema parentSc
     public Set<ValidationMessage> validate(ExecutionContext executionContext, JsonNode node, JsonNode rootNode, String at) {
         debug(logger, node, rootNode, at);
 
-        Set<ValidationMessage> errors = new LinkedHashSet<ValidationMessage>();
         if (node.isNumber()) node = DecimalNode.valueOf(node.decimalValue());
         if (!nodes.contains(node) && !( this.validationContext.getConfig().isTypeLoose() && isTypeLooseContainsInEnum(node))) {
-            errors.add(buildValidationMessage(at, error));
+            return Collections.singleton(buildValidationMessage(null, at, executionContext.getExecutionConfig().getLocale(), error));
         }
 
-        return Collections.unmodifiableSet(errors);
+        return Collections.emptySet();
     }
 
     /**