Grails: how to programatically bind command object data to domain object in service?

Question

I have a command object that I want to convert into a domain object.

However, the object I want to convert the command object into may be one of two domain classes (they're both derived classes), and I need to do it in a service (which is where, based on other data, I decide which type of object it should be bound to). Is this possible and what's the best way to do this? bindData() only exists in a controller.

Do I just have to manually map command object parameters to the appropriate domain object properties? Or is there a faster/better way?

Answer 1

If the parameters have the same name, then you can use this question to copy the values over. A quick summary can be as follows.

Using the Grails API

You can cycle through the properties in a class by accessing the properties field in the class.

object.properties.each { property -> 
    // Do something
}

You can then check to see if the property is present in the other object.

if(otherObject.hasProperty(property) && !(key in ['class', 'metaClass']))

Then you can copy it from one object to the other.

Using Commons

Spring has a really good utility class called BeanUtils that provides a generic copy method that means you can do a simlple oneliner.

BeanUtils.copyProperties(object, otherObject);

That will copy values over where the name is the same. You can check out the docs here.

Otherwise..

If there is no mapping between them, then you're kind of stuck because the engine has no idea how to compare them, so you'll need to do it manually.