Improve Performance by Avoiding Null Values

1global with sharing class TagWS {
2
3/* getThreadTags
4*
5* a quick method to pull tags not in the existing list
6*
7*/
8   webservice static List<String>
9   getThreadTags(String threadId, List<String> tags) {
10
11      System.debug(LoggingLevel.Debug,tags);
12
13      List<String> retVals = new List<String>();
14      Set<String> tagSet = new Set<String>();
15      Set<String> origTagSet = new Set<String>();
16      origTagSet.addAll(tags);
17
18// Note WHERE clause optimizes search where Thread__c is not null
19
20      for(CSO_CaseThread_Tag__c t :
21         [SELECT Name FROM CSO_CaseThread_Tag__c
22         WHERE Thread__c = :threadId AND
23         Thread__c != null
24         WITH USER_MODE])
25
26      {
27         tagSet.add(t.Name);
28      }
29      for(String x : origTagSet) {
30   // return a minus version of it so the UI knows to clear it
31         if(!tagSet.contains(x)) retVals.add('-' + x);
32      }
33      for(String x : tagSet) {
34   // return a plus version so the UI knows it's new
35         if(!origTagSet.contains(x)) retvals.add('+' + x);
36      }
37
38      return retVals;
39   }
40}