CODEWITHSUNDEEP
coldfusioncfc
Phil Parsons
Phil Parsons

Reputation: 2887

Creating a new instance from within CFC

Now this would seem to be something very straight forward, but seemingly not so in ColdFusion. I need to create an instance of a CFC from within itself as in var a = new this() but this obviously does not work. The CFC name can't be used as it is a base that will be extended so I am attempting a hack around the issue with the following:

component {
    public function subQuery (required string table) {

        var classPath = getMetaData(this).fullname;
        return createObject("component", classPath).init(table, this.dsn);

    }
}

This would be acceptable but the class path returned from getMetaData(this).fullname is incorrect. The CFC is within a folder named with a hypen as in my-folder and the returned path looks like my.-folder.myCFC with a period inserted before the hyphen. Obviously I could manipulate this string with a Regex but that is just not a road I want to go down.

Hoping someone has a cleaner approach, thanks.

Upvotes: 3

Views: 344

Answers (1)

Simon at The Access Group
Simon at The Access Group

Reputation: 7027

You should be able to do it without any context on the object name in theory, as it will be being executed from within itself and it should check its current directory.

The following should therefore do the job you need

var classPath = ListLast(getMetaData(this).fullname,'.');
return createObject("component", classPath).init(table, this.dsn);

This way it doesn't matter what the directory names are, and it will work on any objects that extend that one regardless of directory structure, or for a complete example

public function cloneMe() {
    return CreateObject('component', ListLast(getMetaData(this).fullname,'.')).init(argumentCollection=arguments);
}

This way any arguments passed in will be passed through into the init. I.e. an extending CFC may redefine the method as the following (if you want errors when the init arguments aren't supplied)

public function cloneMe(required string table) {
    return super.cloneMe(table=arguments.table,dsn=this.dsn);
}

Upvotes: 4

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