Resolver vs. Factory definition, following, interface, criteria, existing

amy

It seems to me that there is a very fine line between what a ‘Resolver’ does and a ‘Factory’. Is there an official definition of these terms (and of course other similar terms) so that we use them correctly?

My current understanding is the following:

Resolver:
Used to look up, or resolve, an existing object based on input criteria. (i.e. ViewResolver). Note that the Spring ViewResolver interface documentation states that some of them in fact create a view instead of just resolving an existing one.

Factory:
Used to create an object based on input criteria. It is often used in place of a simple ‘new’ object creation such that control of the creation of complex object structures can be controlled. (i.e. MyDomainObjectFactory)

As a specific example, we have domain models that have different validation rules depending on how they are used. Therefore, we want to supply a different ‘Validator’ depending on the context.

Should we create a 'Resolver' or 'Factory' to do this?

public interface ValidatorResolver
{   Validator resolveValidator( Object validationContext );
}

... or

public interface ValidatorFactory
{   Validator createValidator( Object validatorContext );
}

... or something else?

Thanks…

Jim Leask

It seems to me that what you described is the common understanding.  A resolver (more commonly known as a locator) focuses on locating existing entities while a factory focuses on creating new entities.