Am implementing records with checkboxes, during pagination process, state of checkbox is not maintaing in front end :( back end its working well, pls help ma issue.

public void init() {        
         wrapperRecordList = new List<WrapperClass>();
         system.debug(setCon.getRecords());
         for (Contact cont : (List<Contact>)setCon.getRecords()) {  
          if(mapHoldingSelectedRecords != null && mapHoldingSelectedRecords.containsKey(cont.id)){
           wrapperRecordList.add(new WrapperClass(cont, false));
           
         }
          else{
          wrapperRecordList.add(new WrapperClass(cont, false));
         }
         }
          system.debug(wrapperRecordList.size()); 
          
         }
         public List<Contact> conlist =  new List<contact>();
         public string doql;
         /** Instantiate the StandardSetController from a query locater*/
         public ApexPages.StandardSetController setCon {
         get {
         if(setCon == null) {
         
            //string soql = 'select id, lastname, name, email, phone from contact Limit :QUERY_LIMIT';
            
             string soql = 'SELECT id,LastName,AssistantName,AssistantPhone,Birthdate,Department,Description,Email,Fax,';
              soql      += 'HomePhone,MailingAddress,MailingCity,MailingCountry,MailingPostalCode,MailingState,datefield__c,To_date__c,' ;
              soql      += 'MailingStreet,MobilePhone,Name,firstname,OtherAddress,OtherCity,OtherCountry,OtherPhone,OtherPostalCode,';
              soql      += 'OtherState,OtherStreet,Account.Name,LastModifiedDate,Phone,Title,Mail_Sent_Date__c,' ;
              soql      += '(SELECT Assistant_Name__c,Assistant_Phone__c,Birthdate__c,Contact__c,CreatedById,'
                        + 'CreatedDate,Department__c,Description__c,Email__c,Fax__c,First_Name__c,Home_Phone__c,Id,IsDeleted,Mailing_City__c,'
                        +'Mailing_Country__c,Mailing_State_Province__c,Mailing_Street__c,Mailing_Zip_Postal_Code__c,Mobile_Phone__c,Name,'
                        +'Other_City__c,Other_Country__c,Other_Phone__c,Other_State_Province__c,Other_Street__c,Other_Zip_Postal_Code__c,'
                        +'OwnerId,Phone__c,Title__c from Cons__r) From Contact  ';
               doql = soql;
                system.debug('doql : ' + doql);
              
            
           setCon = new ApexPages.StandardSetController(Database.getQueryLocator(soql + ' Limit : QUERY_LIMIT' ));
           system.debug(setCon);
        
         }
           //Search();
           return setCon;
         }
         set;
         }
        
         public void countpage(){
         contactPaginationController_utility cu = new contactPaginationController_utility();
             cu.fromDate = fromDate;  
             cu.toDate = toDate;
             cu.lastDate30 = lastDate30 ;
             cu.lastDate60 = lastDate60 ;
             cu.lastDate90 = lastDate90 ;
         
         cu.querybat = querybat;
          cu.countall();
         
         }
          public void Search(){
           
            
              fromDate = con.datefield__c;
              toDate = con.To_date__c;
              directsend = con.schedule_check__c;
              lastDate30 = System.today().addDays(-30);
              lastDate60 = System.today().addDays(-60);
              lastDate90 = System.today().addDays(-90);
              system.debug(doql);
              string whereConditions = 'where ';
              string resultQuery = '' ;
             
                  
              if(con.datefield__c !=null && con.To_date__c !=null){          
                  resultQuery  = doql + whereConditions + ' LastModifiedDate >= :fromDate AND LastModifiedDate <= :toDate' ;
                
              }
              if(Con.Last_Sent_Date__c !='--None--'){
                  resultQuery  =  getLastsentDate(Con.Last_Sent_Date__c ,resultQuery) ;
               //   conlist = database.query(resultQuery + ' Limit : QUERY_LIMIT');
                //  system.debug(conlist);
              }
              if(string.isNotBlank(SelectedOption) && string.isNotBlank(selectedOperatorOption) && string.isNotBlank(enteredText)){
                  resultQuery = getOperatorSelection(SelectedOption,selectedOperatorOption,resultQuery,enteredText) ;
              }  
               system.debug(resultQuery + ' Limit : QUERY_LIMIT');
               
               
                querybat= resultQuery;
                
                if(directsend== true){
                 
                     updatecheck b2 = new updatecheck();
         
             b2.fromDate = fromDate;  
             b2.toDate = toDate;
             b2.lastDate30 = lastDate30 ;
             b2.lastDate60 = lastDate60 ;
             b2.lastDate90 = lastDate90 ;
             b2.queryString = querybat;  
          
             Database.executeBatch(b2); 
            
              
                 }
                else{
                 
                setCon = new ApexPages.StandardSetController(Database.getQueryLocator(resultQuery + ' Limit : QUERY_LIMIT' ));
                   system.debug(setCon.getRecords());
      
                setCon.setPageSize(PAGE_SIZE);
                init();
              
                }
                  system.debug(setCon);
              
           
           }
            public Boolean hasNext {
         get {
           return setCon.getHasNext();
         }
         set;
         }
         
         /** indicates whether there are more records before the current page set.*/
         public Boolean hasPrevious {
         get {
           return setCon.getHasPrevious();
         }
         set;
         }
         
         /** returns the page number of the current page set*/
         public Integer pageNumber {
         get {
           return setCon.getPageNumber();
         }
         set;
         }
         
         /** return total number of pages for page set*/
         Public Integer getTotalPages(){
             Decimal totalSize = setCon.getResultSize();
             Decimal pageSize = setCon.getPageSize();
             Decimal pages = totalSize/pageSize;
             return (Integer)pages.round(System.RoundingMode.CEILING);
         }
         
         /** returns the first page of the page set*/
         public void first() { 
         selectmethod();
          // updateSearchItemsMap();
           setCon.first();   
           init();
         
         }
         
         /** returns the last page of the page set*/
         public void last() {
          selectmethod();
          // updateSearchItemsMap();
           setCon.last();
            init();
         }
         
         /** returns the previous page of the page set*/
         public void previous() {
          selectmethod();
          // updateSearchItemsMap();
           setCon.previous();
           init();
         }
         
         /** returns the next page of the page set*/
         public void next() {
         selectmethod();
         //  updateSearchItemsMap();
           setCon.next();
           init();
         }
         public void selectmethod() {
              system.debug('wrapper size :' + wrapperRecordList);
              if(!wrapperRecordList.isEmpty())
              for(WrapperClass wrp : wrapperRecordList){
              paginationmap.put(wrp.contactRecord.id, wrp);          
              if(wrp.isSelected ){
              mapHoldingSelectedRecords.put(wrp.contactRecord.id, wrp);
             }
             if(wrp.isSelected == false && mapHoldingSelectedRecords.containsKey(wrp.contactRecord.id)){
             mapHoldingSelectedRecords.remove(wrp.contactRecord.id);
              }
 
            }  
              
                         system.debug(mapHoldingSelectedRecords.size());
            
            }