Learning ColdFusion 9: EntityNew() vs. The NEW Operator / CreateObject()

I'm not sure if you made this clear or not, but new() can also work with non-ORM stuff. I love it as it saves me some typing with createObject.

Excellent stuff Ben, I'm enjoying all this new ORM stuff in CF9, I've not had the time or opportunity to crack it open and work with it myself just yet but it really looks excellent.

During your time playing with things have you tried persisting inherited objects? This is something I've always wanted to use in current ORM options such as Transfer but it's not currently supported, I wonder if/how his can be implemented in using the CF9 ORM methods as we use this kind of object model quite extensively here.

Rob

I think I'm right in saying that EntityNew uses Hibernate directly to create the entity, so it has Java performance. Whereas using new has the performance impact of ColdFusion creating the object.

I like using the two methods so that I can see in my code if I'm working with a persisted entity of a plain CFC.

@Rob, I've played around with the hibernate inheritance and find that it works really well. The method I prefer is the one-table-per-entity and the discriminator column.

For example for a user superclass, with a manager subclass my code would be something like this:

/**
* @output false
* @hint I am a User Persisted Entity
* @discriminatorcolumn usertype
* @persistent true
*/
component
{
property name="UserID" ormtype="string" length="32" fieldtype="id" generator="native";
... stuff ....
}

/**
* @output false
* @hint I am a Manager Persisted Entity
* @extends User
* @discriminatorValue PARENT
* @persistent true
* @joinColumn UserID
*/
component
{
... stuff ....
}

One of the differences between CreateObject() and new Object() is that using new Object() will automatically execute the constructor (if it exists).

I haven't tested whether EntityNew() automatically executes the constructor. Have you tested this Ben?

@Ben,

That's great to hear they have a few different options available, seems they're giving pretty extensive access to the underlying hibernate stuff which really does turn me on.

@John,

Thanks, that's certainly quite a clean implementation, I've used some hasked versions of single table inheritance before with Transfer.

At the moment my current model generally has multiple table inheritance going on, for instance we deal with a great deal of multimedia messages, so we'll have a super class of 'message' and then subclasses, each with a different table for 'text', 'picture', 'audio', 'video' and so forth.

Thanks guys,

Rob

i haven't had the chance to play with cf9's orm stuff yet, but i'm wondering if there is anything out there about setting up and doing validations with the orm.

Let me clear the confusion around EntityNew. Its nothing but a shorthand for createObject or New. Performance wise or functionality wise, its exactly the same. The only difference being - EntityNew works on the entityName. That makes its easier for you when you are creating the entity as you don't need to use the fully qualified name of cfc and it gels well with other entity functions.
Lets say one of the entity is "x.y.z.Actor" whose entityname is 'actor'. To create an actor, you would just say EntityNew('actor') no matter what the application mapped directory is, no matter which directory you are calling from, no matter what the fully qualified name is.

Hope that helps.

Not at all. This is object creation and hibernate does not come into the picture here.

@Ben, @Rupesh In that case I apologise for posting incorrect information. I was under the impression that hibernate was being used. Sorry guys!

There are a couple of reasons that I like the EntityNew() function. As Rupesh describes above, it allows one to create an entity without having to know the full path to the cfc. This allows for better encapsulation. It is also consistent with EntityLoad() in that an object can be created solely by knowing the entity name. Why is that useful?

As an example, I might have a save() method in a service, which accepts an ID and a packet of data (e.g., the contents of a form post). I could define the entity name in the service itself (e.g., 'Movie'), and then, when the save method is called I could have code that conditionally chooses whether to retrieve an existing object, via EntityLoad() or create a new object, via EntityNew(), and then populate, validate and save the object.

In fact I can simply create one abstract service that does this, and then create dozens of services that extend that abstract service without having to write (almost) any code for them.

If I were going to use New() instead of EntityNew(), my service would have to know both the entity name and the actual path to the cfc, which seems silly.

Rupesh, I want to pick on one thing you said - that entityNew was nothing but a shorthand for createObject or new. That isn't entirely true. As Devin points out, only NEW actually runs your init method. createObject and entityNew do not. I'm not surprised by createObject not running init, but I'm kinda surprised entityNew does not.

Ben,

Thanks for the post. While I'm not certalnly in EntityNew(), do you know if the "new" directive supports Java classes as well? For example:

<cfset myFile = new java.io.File("myFile.txt")>

I haven't had the chance to play with our new CF9 server extensively yet so maybe the functionality exists. I just came across an instance in one of my CF pages where I'm using some Java classes like so:

<!--- Create the temporary File --->
<cfset oFile = createObject("java", "java.io.File").init("#expandPath(hash(createUUID()) & '.pdf')#")>
<cfset oFileOS = createObject("java", "java.io.FileOutputStream").init(oFile)>
<cfset oBufferedOS = createObject("java", "java.io.BufferedOutputStream").init(oFileOS)>


<!--- Read the BinaryArrayOutputStream from the cfhttp.fileContent --->

<cfset httpFile.fileContent.writeTo(oBufferedOS)>
<cfset oBufferedOS.flush()>
<cfset oBufferedOS.close()>

Generally, in my practice with Java, you would wrap those classes like so:

<cfset oBufferedOS = new java.io.BufferedOutputStream(new java.io.FileOutputStream(new java.io.File("myFile.txt")))>

I have no idea if the "new" directive works with Java though. It would be much nicer than implicitly calling CFCs using createObject().

Ben,

I guess I answered my own question. I got around to playing on our CF9 server and tried to create a File object:

<cfset file = new java.io.File("myFile.txt")>

With the result of:

Could not find the ColdFusion component or interface java.io.File.

However, this works with a CFC.

Darn. That would have been a helpful feature.

Does anyone have an example of the new functionality for entity new in cf 9.01.

Apparently you can pass a struct of properties to to the function. So you can now post a form and pass it into an ORM entity on creation, allowing you to populate it without having to call all of the setters in sequence.

I know you can do this in coldbox with the populate method, and its really helpful. Much better then having to type out entity.setName(FORM.name), entity.setAge(FORM.age) individually for all the properties.

I just havent been able to see an example of it at work got cf 9 .01

Cheers

@John, you do it by passing a struct. For example:

user = EntityNew("User",{name="Ben Nadel", status="CF God"});

@John, if you want to read up on all the CF9.01 stuff, then Bob Silverberg wrote a really good post about it.

http://www.silverwareconsulting.com/index.cfm/2010/7/13/ColdFusion-901-Now-Available--With-ORM-Goodies

Ahh, another favorite of CF9 is the implicit arguments. If I recall, passing an implicit struct or array as an argument would throw an exception in CF8 (at least I had issues with it) so I had to change some code back, but it seems to work perfectly fine in CF9.

Thanks for the response John W.

Yeah i had seen that, but wondered if you could pass a form struct to it?

user = EntityNew("User",form);

As you can do this with in coldbox..

user = entityNew("user")

user.populate(form);

Would make things a lot easier if that was possible in cf 9.0.1, but not seen any examples confirming it.

Hi ben..

Yes I have actually done what you have suggested using a base component created by bob silverberg - http://bit.ly/b57VbL.

Just thought it would be cool if cf9.0.1 had it as default.