can we invoke another class method from batch apex?

Question

can we invoke another class method from batch apex? I need to call EndDateStartDateDifference method (from DaysDifference class) in TimeCalculator batch apex with firstDate value (fetch in query) and finish date value(system.today).

simple class:-

public with sharing class DaysDifference {
    public static integer EndDateStartDateDifference(date firstDate, date finishDate) {
        integer difference= firstDate.daysBetween(finishDate);
        return difference;
    }
}

Batch apex:-

global class TimeCalculator implements Database.Batchable<SObject>{

    global Database.QueryLocator start(Database.BatchableContext context) {
        string getTLRecord = 'SELECT Start_Date__c FROM Time_Log__c';
        return Database.getQueryLocator(getTLRecord);
    }

    global void execute (database.batchableContext context, List<Time_Log__c> scope){
        DaysDifference.EndDateStartDateDifference(??,??);
       
    }

    global void finish(database.batchableContext context){

    }
}

Answer 1

Yes you can, and it's done just like how you would call any other method.

You'll need to loop over the batch's scope to get the start date to pass to your static EndDateStartDateDifference() method. E.g.

for(My_Object__c myRecord :scope){
    // do work
}

You'll also (unsurprisingly) need to provide the end date. Since the end date isn't going to be different from record to record, this is something that you should do outside of (and before) your loop. A simple Date endDate = Date.today(); should do fine.

Be aware that calculating the date difference isn't going to automatically cause your records to be updated. There's not much use in calculating something if you're not going to put that difference into a field or otherwise use it for another purpose. If you're only trying to update your records with this date difference, using a formula field is likely to be the more appropriate solution.