Java-Spring-CRQS-Eventsourcing-Microservice VS hibernate-validator

Source code you can find in GitHub repository The main idea of this project is the implementation of Event Sourcing and CQRS using Java, Spring and EventStore using Postgresql, previously have written same article where implemented the same using Go and EventStoreDB, think EventStoreDB is the best choice for event sourcing, but in real life at some projects we usually have business restrictions and for example usage of the EventStoreDB can be not allowed, in this case think postgres and kafka is good alternative for implementing our own event store. Didn't write in this article about Event Sourcing and CQRS patterns,th e best place to read is microservices.io, blog and documentation of this article is very good too, and as written in previous article, highly recommend Alexey Zimarev "Hands-on Domain-Driven Design with .NET Core" book and also his blog.

Why not use some tool like https://hibernate.org/validator/ ?

Without attempting to define 'right mind', Hibernate validator uses regex based email validation.

/* * This code is based on this PR: https://github.com/hibernate/hibernate-validator/pull/1199 * All credits to Daniel Heid (dheid). I just made some adjustments. * In order to apply this on your situation, just create this class and call the method "isValidStringUUID". As its param, pass in your string UUID. */ public class UUIDValidator { enum LetterCase { /** * Only lower case is valid */ LOWER_CASE, /** * Only upper case is valid */ UPPER_CASE, /** * Every letter case is valid */ INSENSITIVE } private static LetterCase letterCase = LetterCase.LOWER_CASE; private static final int[] GROUP_LENGTHS = { 8, 4, 4, 4, 12 }; public static boolean isValidStringUUID(String value) { if ( value == null ) { return false; } int valueLength = value.length(); if ( valueLength == 0 ) { return false; } else if ( valueLength != 36 ) { return false; } int groupIndex = 0; int groupLength = 0; int checksum = 0; for ( int charIndex = 0; charIndex < valueLength; charIndex++ ) { char ch = value.charAt( charIndex ); if ( ch == '-' ) { groupIndex++; groupLength = 0; } else { groupLength++; if ( groupLength > GROUP_LENGTHS[groupIndex] ) { return false; } int numericValue = Character.digit( ch, 16 ); if ( numericValue == -1 ) { // not a hex digit return false; } if ( numericValue > 9 && !hasCorrectLetterCase( ch ) ) { return false; } checksum += numericValue; } } // NIL UUID if ( checksum == 0 ) { return false; } return true; } private static boolean hasCorrectLetterCase(char ch) { if ( letterCase == null ) { return true; } if ( letterCase == LetterCase.LOWER_CASE && !Character.isLowerCase( ch ) ) { return false; } return letterCase != LetterCase.UPPER_CASE || Character.isUpperCase( ch ); } }

Our microservice accept http requests: For swagger used Swagger OpenAPI 3. The bank account REST controller, which accept requests, validate it using Hibernate Validator, then call command or query service. The main reason for CQRS gaining popularity is the ability to handle reads and writes separately due to severe differences in optimization techniques for those much more distinct operations.

I'm trying to build a specific sub module of an open source library.