Populate StandardSetController from API

.cls

public ApexPages.StandardSetController itemsSetController{
        get{
            if(itemsSetController == null) {
                Item__c[] items = new Item__c[]{};
                HttpRequest req = new HttpRequest();
                req.setEndpoint('https://'+URL.getSalesforceBaseUrl().getHost()+'/services/data/v35.0/query/?q=SELECT+Id,Name+FROM+Item__c+WHERE+'where_clause'+ORDER+BY+Name+ASC');
                req.setMethod('GET');
                req.setHeader('Authorization', 'Bearer '+ userInfo.getsessionId());
                Boolean done = false;
                do{ JSONParser parser = JSON.createParser(new Http().send(req).getBody());
                    while(parser.nextToken() != null){
                        if(parser.getCurrentToken() == JSONToken.FIELD_NAME && parser.getText()=='totalSize'){
                            parser.nextToken();
                            totalSize = already_added.isEmpty()||!String.isBlank(search_string) ? parser.getIntegerValue() : parser.getIntegerValue()-already_added.size();
                        }
                        if(parser.getCurrentToken() == JSONToken.START_ARRAY)
                            while(parser.nextToken() != null)
                                if(parser.getCurrentToken() == JSONToken.START_OBJECT && items.size()<50)
                                    items.add((Item__c)parser.readValueAs(Item__c.class));
                        if(parser.getCurrentToken() == JSONToken.FIELD_NAME && parser.getText()=='done'){
                            parser.nextToken();
                            done = parser.getBooleanValue();
                        }
                        if(parser.getCurrentToken() == JSONToken.FIELD_NAME && parser.getText()=='nextRecordsUrl'){
                            parser.nextToken();
                            req.setEndpoint('https://'+URL.getSalesforceBaseUrl().getHost()+parser.getText());
                        }
                    }
                }while(!done);
                //populate StandardSetController
                itemsSetController = new ApexPages.StandardSetController(items);
                itemsSetController.setPageSize(5);
                //set totalPages
                Integer count=1;
                if(itemsSetController.getHasNext()){
                    while(itemsSetController.getHasNext()){
                        count++;
                        itemsSetController.next();
                    }
                    itemsSetController.first();
                }
                totalPages = count;
            }
            return itemsSetController;
        }
        set;
    }