CycleAvoidingMappingContext uses Lombok Builder instead of TargetType

[ffroliva]

Hi,

I have a bidirectional mapping Father <--> Children and I decided to try to use this CycleAvoidingMappingContext from the example: https://github.com/mapstruct/mapstruct-examples/blob/master/mapstruct-mapping-with-cycles/src/main/java/org/mapstruct/example/mapper/CycleAvoidingMappingContext.java

I have a builder class in my Entity and DTO from Lombok but I believe the problem seems to happen also without it.

When the MapperStruct processor created the Mapper Implementation the context object is trying to use the Entity/DTO Builder as the actual targetType which caused compilation error.

I have created a sample project that reproduces the problem. Please have a look.

mapstruct-mapping-with-cycles.zip

I tried to introduce generics to the CycleAvoidingMappingContext to eliminate this problem but it didn't help? When I introduced generics and removed the @TargetType Class<T> targetType from getMappedInstance method the Mapper implementation no longer is added to the Mapper implementation.

public class CycleAvoidingMappingContext<S, T> {
    private final Map<S, T> knownInstances = new IdentityHashMap<S, T>();

    @BeforeMapping
    public T getMappedInstance(S source) {
        return knownInstances.get( source );
    }

    @BeforeMapping
    public void storeMappedInstance(S source, @MappingTarget T target) {
        knownInstances.put( source, target );
    }
}

public class EmployeeMapperImpl implements EmployeeMapper {

    @Override
    public Employee toEmployee(EmployeeDto employeeDto, CycleAvoidingMappingContext<EmployeeDto, Employee> context) {
        if ( employeeDto == null ) {
            return null;
        }

        EmployeeBuilder employee = Employee.builder();

        employee.name( employeeDto.getEmployeeName() );
        employee.reportsTo( toEmployee( employeeDto.getReportsTo(), context ) );
        employee.team( employeeDtoListToEmployeeList( employeeDto.getTeam(), context ) );

        return employee.build();
    }

    @Override
    public EmployeeDto fromEmployee(Employee employee, CycleAvoidingMappingContext<Employee, EmployeeDto> context) {
        if ( employee == null ) {
            return null;
        }

        EmployeeDtoBuilder employeeDto = EmployeeDto.builder();

        employeeDto.employeeName( employee.getName() );
        employeeDto.reportsTo( fromEmployee( employee.getReportsTo(), context ) );
        employeeDto.team( employeeListToEmployeeDtoList( employee.getTeam(), context ) );

        return employeeDto.build();
    }

    protected List<Employee> employeeDtoListToEmployeeList(List<EmployeeDto> list, CycleAvoidingMappingContext<EmployeeDto, Employee> context) {
        if ( list == null ) {
            return null;
        }

        List<Employee> list1 = new ArrayList<Employee>( list.size() );
        for ( EmployeeDto employeeDto : list ) {
            list1.add( toEmployee( employeeDto, context ) );
        }

        return list1;
    }

    protected List<EmployeeDto> employeeListToEmployeeDtoList(List<Employee> list, CycleAvoidingMappingContext<Employee, EmployeeDto> context) {
        if ( list == null ) {
            return null;
        }

        List<EmployeeDto> list1 = new ArrayList<EmployeeDto>( list.size() );
        for ( Employee employee : list ) {
            list1.add( fromEmployee( employee, context ) );
        }

        return list1;
    }
}

Any Ideas?

Regards,

Flávio Oliva

[turo-90]

Did you fix the problem, I have the same bug in version 14.2.Final In version 1.5.0.Beta1, code compiles, but unit tests indicate StackOverflow

[ffroliva]

For the time being, I simply removed the builder from my class which was unfortunate! That's how I went forward!

This bug from what I could understand needs to be fixed within MapStruct Annotation Processor engine.

As I said, if I introduce generics to CycleAvoidingMappingContext the getMappedInstance method from the context instance no longer gets introduced in the beginning of the converter. That's why you are probably facing this Stackoverflow.

[PunKHS]

I have the same problem in version 1.4.2.Final with lombok 1.18.12

[filiphr]

When you are using builders the lifecycles are treated slightly differently have a look at https://github.com/mapstruct/mapstruct/issues/1454.

For the time being, I simply removed the builder from my class which was unfortunate! That's how I went forward!

You don't have to do that. You can always use something like;

• @BeanMapping( builder = @Builder( disableBuilder = true ) )
• @Mapper(builder = @Builder(disableBuilder = true))

I am going to close this issue since the relevant things around this are in https://github.com/mapstruct/mapstruct/issues/1454