how to get value from map when wrapper class is the key

Question

I have a wrapper class of picklist values and labels. I am creating a map with picklistValues and List as key and value types. Now, I am getting an error won this line -- objResults.get(controlPicklist).add(depPicklist);

It is saying that i am referencing a null object. When I do show just this line -- >objResults.get(controlPicklist), the value is null, wherein it should return (). Unless I am constructing the key wrong?

Here are what displays on my debug logs.

ObjResults Controllers: objResults controllers : {picklistValues:[label=CustomerService, value=CustomerService]=(), picklistValues:[label=OCM, value=OCM]=(), picklistValues:[label=Facilities Management, value=Facilities Management]=(), picklistValues:[label=Accounts, value=Accounts]=(), picklistValues:[label=Marketing PR, value=Marketing PR]=(), picklistValues:[label=Talent Management, value=Talent Management]=(), picklistValues:[label=Sales, value=Sales]=(), picklistValues:[label=Admin, value=Admin]=()}

---

controllerValues controllers : {0=CustomerService, 1=OCM, 2=Facilities Management, 3=Accounts, 4=Marketing PR, 5=Talent Management, 6=Sales, 7=Admin}

---

controlPicklist : picklistValues:[label=CustomerService, value=CustomerService]

---

public class picklistValues{
        @AuraEnabled public String value {get;set;}
        @AuraEnabled public String label {get;set;}
    }

Map<picklistValues,List<picklistValues>> objResults = new Map<picklistValues,List<picklistValues>>();
    for(String controller : pvw.controllerValues.keySet()){
                    controllerValues.put(pvw.controllerValues.get(controller),controller);
                    picklistValues picklist = new picklistValues();
                    picklist.value = controller;
                    picklist.label = controller;
                    objResults.put(picklist,new List<picklistValues>());
                }
                system.debug('objResults controllers : ' + objResults);
                system.debug('controllerValues controllers : ' + controllerValues);

                for(fieldValues field : pvw.values){
                    for(String index : field.validFor){
                        String controllerField = controllerValues.get(Integer.valueOf(index));
                        system.debug('controllerField : ' + controllerField);

                        picklistValues controlPicklist = new picklistValues();
                        controlPicklist.label = controllerField;
                        controlPicklist.value = controllerField;
                        system.debug('controlPicklist ' + controlPicklist);

                        picklistValues depPicklist = new picklistValues();
                        depPicklist.value = field.value;
                        depPicklist.label = field.label;
                        system.debug(objResults.keySet());
                        system.debug(objResults.containsKey(controlPicklist));
                        objResults.get(controlPicklist).add(depPicklist);                    
                    }
                }

Answer 1

I think that this error is misleading. At least I'm getting nothing from it.

My first suspicion what is wrong: You're trying to use your custom created class as a map key but you don't have equals and hashcode methods implemented for it. Normally when you're using SObjects or primitive data types, you dont need to do that.

Example implemantation here:

public class PairNumbers {
Integer x,y;

public PairNumbers(Integer a, Integer b) {
    x=a;
    y=b;
}

public Boolean equals(Object obj) {
    if (obj instanceof PairNumbers) {
        PairNumbers p = (PairNumbers)obj;
        return ((x==p.x) && (y==p.y));
    }
    return false;
}

public Integer hashCode() {
    return (31 * x) ^ y;
}
}

Full article for reference here: https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/langCon_apex_collections_maps_keys_userdefined.htm

I would also recommend moving this wrapper to entire new class as I'm not so sure if apex is intelligent enough to connect hashcode and equals with inner class