HI,
I have a apex class which is generating a report based on Query.I want to give a numer for that set of records.So for each time report generation a new number will be generate and post that number in all the record fetch in that report.How to do that.Please help.
Class
public with sharing class GenerateDtfCase {

    public GenerateDtfCase() {

    }

//public POSDetails__c customerObj{get;set;}
  Public List<Case> customerObj = new List<Case>();
  public List<Case> getcustomerObj(){return customerObj;}

  Public List<Employee_Master__c> Emp{get;set;}
  public String branchcode{get;set;} 
  public Case trnObj = new case();
  public Case gettrnObj(){return trnObj;}
  
  public list<case> upcase = new list<case>();
   
  //public String cityBranch {get;set;} 
public Date Today { get { return Date.today(); }}
    public GenerateDtfCase(ApexPages.StandardController controller) {
      try
        {
            Emp= [Select e.User__r.Id, e.User__c, e.Id, e.Branch_Code__r.BranchCode__c, e.Branch_Code__r.Cash_inCounter_Limit__c, 
                  e.Branch_Code__r.Cash_in_Safe_Limit__c, e.Branch_Code__r.Name, e.Branch_Code__c 
                  From Employee_Master__c e where User__r.Id = : UserInfo.getUserId() and Active__c= : true  limit 1];
            
            if(Emp[0].Branch_Code__r.BranchCode__c!= null)
            {
               
                branchcode=Emp[0].Branch_Code__r.Name;
            }else{
                ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR, 'No Branch mapping found in Employee master for the logged in user.  Please contact the system administrator to get it corrected.'));
            }
        }catch(exception e){
            ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR, 'No mapping record found in Employee Master for the Logged in user. Please contact the system administrator to get it corrected.'));
        }
    system.debug('branch code:'+branchcode);
    
    //customerObj = [select id, Name,Complete_Status__c,Branch_name__c,Creation_Date__c,Document_List__c,Vertical__c,Status__c,DTF_Creation_Date__c,Effective_date_of_coverage__c,Policy_No__c,proposal_Application_no__c,proposal_Name__c,Request_Type__c,Request_Type_new_del__c,Branch__c ,Supporting_Document_del__c 
    //FROM POSDetails__c WHERE Vertical__c='LI' AND Branch__r.Name =:branchcode];
    
//customerObj = [select id, Name, Complete_Status__c, Branch_name__c,Branch__r.Name , Creation_Date__c, Document_List__c, Vertical__c, Status__c, DTF_Creation_Date__c, Effective_date_of_coverage__c, Policy_No__c, proposal_Application_no__c, proposal_Name__c, Request_Type__c, Request_Type_new_del__c, Branch__c, Supporting_Document_del__c, OwnerId from POSDetails__c where (Vertical__c = 'LI'and Branch__r.Name =:branchcode)];
system.debug('test query branch:'+branchcode);
system.debug('test query customerObj:'+customerObj );
//ModifyCase();
    }
    
    public void ModifyCase() {
    System.debug('====customerObj:'+customerObj);
      for(Case c: [select id,CaseNumber,Branch_name__c,Account_Name__c,Proposal_Detail__c,Branch_Code__c,DTF_No2__c,Principal_code__c,Policy_Number__c,Creation_Date__c,Document_List__c,Vertical__c,DTF_Creation_Date__c,Effective_date_of_coverage__c,Request_Type__c,Supporting_Document__c 
    FROM Case WHERE (RecordTypeID ='012O00000005BMS' AND DTF_Creation_Date__c=null AND Vertical__c =: trnObj.Vertical__c AND Principal_code__c =: trnObj.Principal_code__c)]) {
      
            customerObj.add(c);
            case ics = new case();
            ics.id = c.id;
            ics.DTF_Creation_Date__c = System.today();
            ics.DTF_No2__c = c.Branch_Code__c +c.CaseNumber+ System.today();
            upcase.add(ics);
             
     }
     
     if(!upcase.isempty()){
        update upcase;
     }
    } 
    Public pageReference exportReport(){
    PageReference pg=ApexPages.currentPage();
     
        // System.Debug('>>>>>>>>>>>Date Test:>>>>>>>>>>'+trnObj.DTF_genarated_date__c);
        pg=new PageReference('/apex/Genarate_DTF_for_Case?vert='+ trnObj.Vertical__c +'&pricode='+trnObj.Principal_code__c);
        pg.setredirect(true);
        return pg;
    }
}