Is it possible to use results from a batch job in normal apex class?

Question

I have a normal apex class, but since the no of records returned from a certain query (highlighted in code) is exceeding governor limits, I wish to replace that with a batch job, which will calculate the results and store in a collection. I intent to use that collection for the remaining logic in my apex class. Is it possible?

Note: I also have a visualforce page which references this apex class to display data. The highlighted section is where my code says cpu timeout exceeded, but I believe the subsequent lines of code also need to be replaced and passed into the batch job.

global class Persona_Custom_Metadata_V4 {
    public Map<String, String> PersonaSetting {get;set;}
    public List<User> usrList {get;set;}
    public Map<ID, User> usrMap {get;set;}
    public List<PermissionSetAssignment> PermList {get;set;}
    public Map<Id,List<String>> mapPermList {get;set;}
    public List<string> StorePermSets {get;set;}
    public Set<String> PSSet {get;set;}
    public  List <integer> CountofPS {get;set;}
    public List <Persona_Test__mdt> PersonaMDT {get;set;}
    
    public Id[] userIdsMiss { get; set; }
    public Id[] userIdsAdd { get; set; }
    
    public Id[] userIdsMiss2 { get; set; }
    public Id[] userIdsAdd2 { get; set; }
    
    public Map<ID, User> usrMapPersona1 {get;set;}
    public Map<ID, User> usrMapPersona2 {get;set;}
    
    public Map<ID, Integer> CountofPSMap {get;set;}
    public Map<ID, List<String>> MissingUser {get;set;}
    public Map<ID, List<String>> AdditionalUser {get;set;}
    public List<String> MissingList {get;set;}
    public List<String> AdditionalList {get;set;}
    public List<String> CombinedList {get;set;}
    public Map<ID, List<String>> finalMissingMap {get;set;}
    public Map<ID, List<String>> finalAdditionalMap {get;set;}
    public Map<ID, List<String>> Persona1Missing {get;set;}
    public Map<ID, List<String>> Persona2Missing {get;set;}
    public Map<ID, List<String>> Persona1Additional {get;set;}
    public Map<ID, List<String>> Persona2Additional {get;set;}
    
    public Map<ID, List<String>> PersonaAdditionalTest {get;set;}
    public Map<ID, List<String>> PersonaMissingTest {get;set;}
    public String selectedRT{get;set;}
    public boolean pb2Rendered{get;set;}
    public boolean pb3Rendered{get;set;} 
    public boolean isExport{get; set;}
    
    public void getUserDetails()
    {
        usrMapPersona1 = new Map<ID, User>();
        usrMapPersona2 = new Map<ID, User>();
        
        userIdsMiss = new Id[0];
        userIdsAdd = new Id[0];
        
        userIdsMiss2 = new Id[0];
        userIdsAdd2 = new Id[0];

        Persona1Additional = new Map<ID, List<String>>();
        Persona2Additional = new Map<ID, List<String>>();
        Persona1Missing = new Map<ID, List<String>>();
        Persona2Missing = new Map<ID, List<String>>();
        PersonaSetting = new Map<String, String> ();
        usrList = new list<user>();
        usrMap = new Map<ID, User>();
        PermList = new list<PermissionSetAssignment>();
        mapPermList = new Map<Id,List<String>>();
        StorePermSets = new List<String>();
        PSSet = new Set<String>();
        CountofPS = new list<integer>();
        PersonaMDT = new list <Persona_Test__mdt>();
        CountofPSMap = new Map<ID, Integer>();
        MissingUser = new Map<ID, List<String>>();
        AdditionalUser = new Map<ID, List<String>>();
        MissingList = new List<String>();
        AdditionalList = new List<String>();
        CombinedList = new List<String>();
        finalMissingMap = new Map<ID, List<String>>();
        finalAdditionalMap = new Map<ID, List<String>>();
        
        for (Persona_Test__mdt PersonaMDTRecords : Persona_Test__mdt.getAll().values())
        {
            String PersonaPSset = PersonaMDTRecords.PS_Set__c.trim();
            PersonaSetting.put(PersonaMDTRecords.Identity_PS__c, PersonaPSset);
        }
        
        for (String str:PersonaSetting.keyset() )
        {
            PermList = new List<PermissionSetAssignment>();
            usrMap = new Map<ID, User>();
            usrList = new list<user>();
            mapPermList = new Map<Id,List<String>>();
            MissingUser = new Map<ID, List<String>>();
            AdditionalUser = new Map<ID, List<String>>();
            PersonaMDT = [SELECT Id, Count_of_Unique_PS__c FROM Persona_Test__mdt WHERE Identity_PS__c = :str ];
            Integer CountPS = Integer.valueOf(PersonaMDT.get(0).Count_of_Unique_PS__c);
            system.debug(CountPS);
            usrList = [SELECT Id, firstname, lastname, profile.name, division, department
                       FROM User
                       WHERE  Id IN (SELECT AssigneeId
                                     FROM PermissionSetAssignment
                                     WHERE PermissionSet.label = :str)] ;
            //system.debug(usrList);
            usrMap.putall(usrList);
            
            if (str == 'Test Chatter Free7')
            {
                usrMapPersona1 = usrMap;
            }
            
            if (str == 'Test Chatter Free8')
            {
                usrMapPersona2 = usrMap;
            }
            
            ****PermList =  [SELECT AssigneeId, PermissionSet.label
                         FROM PermissionSetAssignment WHERE AssigneeId = : usrMap.keySet()];****
            for(PermissionSetAssignment perm : PermList){
                if(mapPermList.containsKey(perm.AssigneeId)){
                    List<String> temp =  mapPermList.get(perm.AssigneeId);
                    temp.add(perm.PermissionSet.label);
                    
                    for (Integer i = (temp.size() - 1) ; i >= 0 ; i--){
                        String s = temp[i];
                        if(s.contains('00e1a000000MWaTAAW')){
                            temp.remove(i);
                        }
                    }
                    
                    mapPermList.put(perm.AssigneeId,temp);
                }
                else{
                    mapPermList.put(perm.AssigneeId,new List<String>{perm.PermissionSet.label});
                }
            }
            //system.debug(mapPermList);
            // to store the count of PS
            for (Id idvalue: mapPermList.keyset())
            {
                Integer count = 0;
                for (String s: mapPermList.get(idvalue))
                {
                    //system.debug(' Map keyset Id Value' + idValue );
                    //system.debug(' list values : '+ s);
                    count++;
                    CountofPSMap.put(idvalue, count);
                }

                if (count < CountPS)
                {
                    //String str1 = String.join( mapPermList.get(idvalue), ', ' );
                    
                    //string concatenate='User ID:'+ '' + idvalue + ' '+ '' + 'PS assigned:' + str + '\n';
                    MissingUser.put(idvalue, mapPermList.get(idvalue));
                    
                    //MissingList.add(concatenate);                    
                }
                else if (count > CountPS)
                {
                    String str2 = String.join( mapPermList.get(idvalue), ', ' );
                    
                    string concatenate2 = 'User ID:'+ '' + idvalue + ' '+ '' + 'PS assigned:' + str2 + '\n';
                    AdditionalUser.put(idvalue, mapPermList.get(idvalue));
                    //AdditionalList.add(concatenate2);
                }
            }
            
            if (str == 'Test Chatter Free7')
            {
                Persona1Missing = MissingUser;
                Persona1Additional = AdditionalUser;
                
                //PersonaAdditionalTest = Persona1Additional;
                //PersonaMissingTest = Persona1Missing;
                for (ID idmissing : Persona1Missing.keyset())
                {
                    userIdsMiss.add(idmissing);
                }
                
                for (ID idadd : Persona1Additional.keyset())
                {
                    userIdsAdd.add(idadd);
                }
            }
            else if (str == 'Test Chatter Free8')
            {
                Persona2Missing = MissingUser;
                Persona2Additional = AdditionalUser;
                for (ID idmissing2 : Persona2Missing.keyset())
                {
                    userIdsMiss2.add(idmissing2);
                }
                
                for (ID idadd2 : Persona2Additional.keyset())
                {
                    userIdsAdd2.add(idadd2);
                }
                
                Persona2Missing = MissingUser;
                Persona2Additional = AdditionalUser;
                
                // PersonaAdditionalTest = Persona2Additional;
                // PersonaMissingTest = Persona2Missing;
            }
            
            /*system.debug(Persona1Missing);
            system.debug(Persona2Missing);
            system.debug(Persona1Additional);
            system.debug(Persona2Additional);*/
            //system.debug(CountofPSMap);
            // system.debug('Missing PS User---->' + '\n' + MissingList);
            // system.debug('Additional PS User---->' + '\n' + AdditionalList);
            // CombinedList.addAll(MissingList);
            // CombinedList.addAll(AdditionalList);
            // return CombinedList;
            //finalMissingMap =  MissingUser;
            //finalAdditionalMap =  AdditionalUser;
            // finalList = CombinedList;
            // system.debug(finalMissingMap);
            //system.debug(finalAdditionalMap);
            
            //system.debug('Test---->' + '\n' + finalList);
            
            // MissingUser = new Map<ID, List<String>>();
            //AdditionalUser = new Map<ID, List<String>>();
            // system.debug(MissingUser);
        }
        
        if (selectedRT == 'Persona1')
        {
            pb2Rendered = true;
            pb3Rendered = false;
            //Persona1Missing = MissingUser;
            // Persona1Additional = AdditionalUser;
                        
            PersonaAdditionalTest = Persona1Additional;
            PersonaMissingTest = Persona1Missing;
        }
        else if (selectedRT == 'Persona2')
        {
            pb3Rendered = true;
            pb2Rendered = false;
            // Persona2Missing = MissingUser;
            // Persona2Additional = AdditionalUser;
            
            PersonaAdditionalTest = Persona2Additional;
            PersonaMissingTest = Persona2Missing;
        }
        else if (selectedRT == 'All')
        {
            pb3Rendered = true;
            pb2Rendered = true;
            // Persona2Missing = MissingUser;
            // Persona2Additional = AdditionalUser;
            
            PersonaAdditionalTest = Persona2Additional;
            PersonaMissingTest = Persona2Missing;
        }        
    }
    
    public void getExport() { isExport= true; }
}

Answer 1

The technical answer to your question is:

• If the VF page launches a batch job, the job executes asynchronously
• Thus, when the batch job finishes is indeterminate
• As such, for the VF page to recognize the results of the batch job basically boil down to:
  • the batch job's finish() must save the results in a persistent store (i.e., the database as records)
  • the VF page must poll for the data (classically, done <apex:actionPoller>

The above is a complicated design and @gauravsharma comment is valid - look for ways to optimize the VF controller logic to not run into CPU limits