Nova Mapper Utils

Object-to-object mapping without an annotation processor and without a framework. Where MapStruct generates code at compile time, this maps at runtime through a cached reflection layer — the trade is a little speed for zero build-time machinery.

What's inside

Package	Type	Does
—	MapperEngine	The entry point: map, mapList, mapSet
config	MappingConfig, FieldMapping	Renames, exclusions, nested configs
converter	TypeConverter, DefaultConverters	Conversion between field types
reflect	ReflectionCache, ObjectInstantiator, FieldInfo	The cached reflection layer
result	MappingResult	What mapped, what did not
—	NullStrategy	What to do with a null source field

Install

Published to GitHub Packages, so the repository needs to be declared and authenticated with a token that has read:packages.

repositories {
    maven {
        url = uri("https://maven.pkg.github.com/ahincho/nova-java-03-mapper-utils")
        credentials {
            username = providers.gradleProperty("gpr.user").orNull ?: System.getenv("GITHUB_ACTOR")
            password = providers.gradleProperty("gpr.key").orNull ?: System.getenv("GITHUB_TOKEN")
        }
    }
}

dependencies {
    implementation("pe.edu.nova.java.libs:nova-mapper-utils:0.1.0-SNAPSHOT")
}

Use

The common case needs no configuration:

import pe.edu.nova.java.libs.mapper.utils.MapperEngine;

CustomerDto dto = MapperEngine.map(customer, CustomerDto.class);
List<CustomerDto> dtos = MapperEngine.mapList(customers, CustomerDto.class);

When names differ or a field should not travel, describe it once:

MappingConfig config = MappingConfig.builder()
    .field("createdAt", "created")
    .exclude("passwordHash")
    .nullStrategy(NullStrategy.SKIP)
    .build();

CustomerDto dto = MapperEngine.map(customer, CustomerDto.class, config);

config.reverse() gives you the mapping back the other way without declaring it twice.

Errors

FieldNotFoundException, TypeConversionException, NullFieldException, ObjectInstantiationException and MappingConfigException, all under MappingException.

Requirements

Java 25.

License

Eclipse Public License 2.0 — see LICENSE.

Copyright © 2026 Angel Hincho.