Inherited Properties in a CFC

[JEAguilar]

Hi,

I'm not sure if this is a bug or just my misunderstanding of how CFC inheritance should work. Assume the following three files:

Parent.cfc

component displayname="Parent" accessors="true" {
 property name="ID" type="numeric" access="private";
 property name="Name" type="string";
}

Child.cfc

component displayname="Child" accessors="true" extends="Parent" {
 property name="ChildID" type="numeric";
 property name="ChildName" type="string";
}

test.cfm

<cfscript>
CHILD = new Child();

CHILD.setID(123);
CHILD.setName("ABC");
CHILD.setChildId(987);
CHILD.setChildName("ZYX");

echo( CHILD.ID & " " & CHILD.Name );
echo( serializeJSON(CHILD) );
</cfscript>

I can verify that the inherited ID and Name are being set. And the accessors are being inherited as well. The output of test.cfm is:

123 ABC
{"ChildID":987,"ChildName":"ZYX"}

I would expect the output to be:

123 ABC
{"ChildID":987,"ChildName":"ZYX","ID":123,"Name":"ABC"}

If I dump(CHILD), I get the following:

Component (Child) Child Only the functions and data members that are accessible from your location are displayed
Extends	Parent
	Properties ChildID number 987 ChildName string ZYX public getChildID Public Function getChildID (generated) source:/Users/juan/Sites/Child.cfc arguments label name required type default hint return type numeric setChildName Public Function setChildName (generated) source:/Users/juan/Sites/Child.cfc arguments label name required type default hint ChildName true string null return type any getChildName Public Function getChildName (generated) source:/Users/juan/Sites/Child.cfc arguments label name required type default hint return type string getName Public Function getName (generated) source:/Users/juan/Sites/Child.cfc arguments label name required type default hint return type string setChildID Public Function setChildID (generated) source:/Users/juan/Sites/Child.cfc arguments label name required type default hint ChildID true numeric null return type any setName Public Function setName (generated) source:/Users/juan/Sites/Child.cfc arguments label name required type default hint Name true string null return type any setID Public Function setID (generated) source:/Users/juan/Sites/Child.cfc arguments label name required type default hint ID true numeric null return type any getID Public Function getID (generated) source:/Users/juan/Sites/Child.cfc arguments label name required type default hint return type numeric

with the Parent properties missing. So, am I confused, missing something blindingly obvious, or is this a bug?

Thanks,

Juan

[Chris Blackwell]

I don't think you are misunderstanding how inheritance works.  IMHO, this is a bug in serializeJson().

You can fix it by including a _toJson() function in your parent cfc that properly serializes all inherited properties.

Here's a basic example that assumes all your properties have a public getter function

function _toJSON() {

var data = {};

var meta = getMetaData(this);

var props = [];

while(structKeyExists(meta, 'extends')) {

if(structKeyExists(meta, 'properties')) {

for(var p in meta.properties) {

props.append(p);

}

}

meta = meta.extends;

}

for(var p in props) {

data[p.Name] = this["get#p.Name#"]();

}

return serializeJSON(data);

}

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[Jared Rypka-Hauer]

If you look at the dump of CHILD, you have the top cell that says Component (Child) Child.

Just below that you have:

Extends: Parent

That should be clickable… if you click on it it should expand to so you the parent’s methods and properties as well.

As for your serializeJSON(), You’d be better off to use a method on the parent object that returns a JSON string representing the fields of the object from the parent and child. You don’t want to be breaking encapsulation by having external code directly accessing the contents of the object anyway. :)

On the other hand… it does seem like a bug… since IS-A is how we describe the parent-child relationships, you’d think the child object would present all the fields of both itself and the parent combined. If serializeJSON() will allow you to see the properties of the child it should allow you to see the properties of the whole inheritance chain…

Something to think about, anyway...

J

On Jul 30, 2014, at 7:17 AM, JEAguilar <jeag...@gmail.com> wrote:

Hi,

I'm not sure if this is a bug or just my misunderstanding of how CFC inheritance should work. Assume the following three files:

Parent.cfc

component displayname="Parent" accessors="true" {
 property name="ID" type="numeric" access="private";
 property name="Name" type="string";
}

Child.cfc

component displayname="Child" accessors="true" extends="Parent" {
 property name="ChildID" type="numeric";
 property name="ChildName" type="string";
}

...