Handle field_name in runtime

Author: yevhenii-nadtochii

java-runtime/src/main/java/io/spine/validate/RequiredFieldCheck.java

@@ -59,18 +59,26 @@ final class RequiredFieldCheck {
     Optional<ConstraintViolation> perform() {
         var matches = alternatives.stream()
                 .anyMatch(this::allPresent);
+        if (matches) {
+            return Optional.empty();
+        }
+
         var message = TemplateString.newBuilder()
                 .setWithPlaceholders(ERROR_MESSAGE)
                 .putPlaceholderValue(RULE_VALUE, optionValue)
                 .build();
-        return matches
-               ? Optional.empty()
-               : Optional.of(ConstraintViolation.newBuilder()
-                                     .setMessage(message)
-                                     .setFieldPath(fieldPath())
-                                     .setTypeName(typeName())
-                                     .build()
-               );
+        var fieldPath = fieldPath();
+        var violation = ConstraintViolation.newBuilder()
+                .setMessage(message)
+                .setTypeName(typeName());
+
+        if (fieldPath.getFieldNameCount() == 1) {
+            violation.setFieldName(fieldPath.getFieldName(0));
+        } else {
+            violation.setFieldPath(fieldPath);
+        }
+
+        return Optional.of(violation.build());
     }
 
     private boolean allPresent(Alternative alternative) {

java-runtime/src/main/java/io/spine/validate/Validate.java

@@ -297,7 +297,7 @@ private static ConstraintViolation violatedSetOnce(FieldDeclaration declaration)
                 .build();
         var violation = ConstraintViolation.newBuilder()
                 .setMessage(message)
-                .setFieldPath(declaration.name().asPath())
+                .setFieldName(declaration.name().value())
                 .setTypeName(declaration.declaringType().name().value())
                 .build();
         return violation;

java-runtime/src/main/java/io/spine/validate/diags/ViolationText.java

@@ -28,13 +28,13 @@
 
 import com.google.protobuf.Message;
 import io.spine.annotation.Internal;
-import io.spine.base.Field;
 import io.spine.option.OptionsProto;
 import io.spine.validate.ConstraintViolation;
 
 import java.util.Collection;
 
 import static com.google.common.base.Preconditions.checkNotNull;
+import static io.spine.base.FieldPaths.getJoined;
 import static io.spine.string.Diags.backtick;
 import static io.spine.validate.TemplateStringExtsKt.format;
 import static java.lang.System.lineSeparator;
@@ -86,14 +86,12 @@ public String toString() {
 
     private StringBuilder buildMessage() {
         var typeName = violation.getTypeName();
-        var path = violation.getFieldPath();
-        var fieldPath = path.getFieldNameCount() == 0
-                ? ""
-                : Field.withPath(path).toString();
+        var field = violation.hasFieldName() ? violation.getFieldName()
+                                             : getJoined(violation.getFieldPath());
         var formattedMessage = format(violation.getMessage());
         var result = new StringBuilder();
         appendPrefix(result, typeName);
-        appendPrefix(result, fieldPath);
+        appendPrefix(result, field);
         result.append(formattedMessage);
         return result;
     }

java-runtime/src/main/kotlin/io/spine/validate/MessageValidator.kt

@@ -29,7 +29,6 @@ package io.spine.validate
 import com.google.common.collect.Range
 import com.google.protobuf.Descriptors
 import com.google.protobuf.Message
-import io.spine.base.Field.named
 import io.spine.code.proto.FieldContext
 import io.spine.code.proto.FieldDeclaration
 import io.spine.code.proto.FieldName
@@ -185,12 +184,11 @@ internal class MessageValidator private constructor(private val validatedMessage
         val noneSet = fieldValue.isEmpty
         if (noneSet) {
             val oneofName = constraint.oneofName()
-            val oneofField = named(oneofName.value())
             val targetType = constraint.targetType()
             violations.add(
                 constraintViolation {
                     message = constraint.errorMessage(validatedMessage.context())
-                    fieldPath = oneofField.path()
+                    fieldName = oneofName.value
                     typeName = targetType.name().value
                 }
             )
@@ -266,8 +264,12 @@ private fun violation(
     val typeName = constraint.targetType().name()
     val violation = ConstraintViolation.newBuilder()
         .setMessage(constraint.errorMessage(context))
-        .setFieldPath(fieldPath)
         .setTypeName(typeName.value())
+    if (fieldPath.fieldNameCount == 1) {
+        violation.setFieldName(fieldPath.getFieldName(0))
+    } else {
+        violation.setFieldPath(fieldPath)
+    }
     if (violatingValue != null) {
         violation.setFieldValue(toFieldValue(violatingValue))
     }