Can Wrapper Class Objects be used for Trigger Logic?

Question

Working with Visual Force pages recently I've grown to like the benefits of defining inner class objects to store complex data structure as opposed to multidimensional maps. For example I can easily store aggregated data into an inner object like this simple example:

public CustomClass{
    public class InnerObject{
        public String var1
        public Decimal var2

        public InnerObject(Custom_Object__c record){
            this.var1 = record.Custom1__c;
            this.var2 = record.Custom2__c - record.Custom3__c;
        }
    }

    public void testMethod(List<InnerObject> items){
        for(InnerObject item : items){
            System.debug('::TEST:: '+item.var1);
        }
    }
}

I've tested and found that I can use this in my trigger loop like so:

List<CustomClass.InnerObject> line_items = List<CustomClass.InnerObject>();
if(Trigger.isAfter && Trigger.isInsert){
    for(Custom_Object__c c : (List<Custom_Object__c>) Trigger.new){
        CustomClass.InnerObject line_item = new CustomClass.InnerObject(c);
        System.debug('::LINE ITEM:: '+line_item);

        line_items.add(line_item);
    }
}
CustomClass.testMethod(line_items); // This doesn't work

Sweet! This seems promising thus far but then when I store this in a collection to send to a utility method (as shown above) I keep getting the following error:

Error: Method does not exist or incorrect signature: CustomClass.testMethod(List<CustomClass.InnerObject>)

Is this not possible? Not sure why I can get part of it to work but not the next part, wondering if I'm missing something. Any insight is appreciated, thanks!

Answer 1

You need to either instantiate the class or make the method static:

CustomClass c = New CustomClass();
c.testMethod(line_items);

Or

public static void testMethod(List<InnerObject> items){
        for(InnerObject item : items){
            System.debug('::TEST:: '+item.var1);
        }
    }

then

CustomClass.testMethod(line_items);