How to insert or escape single quotes at beginning and end of a null value or replace null with single quotes only

Question

I have this method below that Returns a String of Id's separated by '|' operator and it works. However now I would like to add on that if an Id is null or blank replace with just single quotes (''). Not sure how to do that. How can i modify this method to do that.

I expect just to see the single quotes only. Example if have strings of ids my result = ('46734'|'3435') What I am looking for if no Ids then I would like to see result =('') or (''|'') not result = ()

public static string getString(Set<Id> setId)
       {
           String strId = '';
           if(setId != null && setId.size() > 0 )
           {
                for(Id RecordId :setId)
                {
                    String strRecordId = RecordId;
                    if(strRecordId.length() > 15){
                        strRecordId = strRecordId.substring(0,15);
                    }
                    strRecordId = '\''+ strRecordId + '\'';
                    strId += strRecordId + '|';
                }
                strId = strId.removeEnd('|');
           } 
           return strId;
       }

Answer 1

You can use the join method from String class like below to get the string of ids seperated by '|' operator:

String.join( new List<String>(String.join(new List<id>(setId), ',').split(',')) , '|' ));

EDIT: check for isNotBlank for every entry in the for loop:

Edit 2: Added empty check for setId.

      public static string getString(Set<Id> setId){

    String strId = '';
    if(setId != null && setId.size() > 0 ){
        for(Id RecordId :setId){  
            String strRecordId  ='';
            if(String.isNotBlank(RecordId)){
                strRecordId = RecordId;
                if(strRecordId.length() > 15){
                    strRecordId = strRecordId.substring(0,15);
                    strRecordId = '\''+ strRecordId + '\'';
                    strId += strRecordId + '|';
                }                        
            }
            else{
                strRecordId = '\' \'';
                strId += strRecordId + '|';
            }
        }
    }
    else{
        strId = '\' \'';
    }
    strId = strId.removeEnd('|');
    return strId ;
}

Answer 2

Here is an alternate approach:

public static String getString(Set<Id> setId){
  if (setId.isEmpty()) {
     return '\'\'';
  }

   List<String> allStrings = new List<String>();

   for (Id currentId : setID) {
      String cleanString = '\'' + (String.isBlank(currentId) ? '' : currentId) + '\'';

      allStrings.add(cleanString);          
   }

   return String.join(allStrings, '|');

}