Is this implementation of the default bag index OK?

[Adam Lally]

A question mainly for Thilo.  This is my idea for implementing the
"default bag index" proposal - that is, when someone calls
IndexRepository.addFS(fs) when there are no indexes defined over the
type of the fs, a bag index will be created:


 public void ll_addFS(int fsRef) {
   // Determine type of FS.
   final int typeCode = this.cas.getHeapValue(fsRef);
   // indicate this type's indexes are being modified
   // in case an iterator is simultaneously active over this type
   incrementIllegalIndexUpdateDetector(typeCode);
   // Get the indexes for the type.
   final ArrayList indexes = this.indexArray[typeCode];
   // Add fsRef to all indexes.
   final int size = indexes.size();
   for (int i = 0; i < size; i++) {
     ((IndexIteratorCachePair) indexes.get(i)).index.insert(fsRef);
   }
   if (size == 0) {
     //lazily create a default bag index for this type
     Type type = this.typeSystem.getType(typeCode);
     String defIndexName = "_" + type.getName() + "_GeneratedIndex";
     FSIndexComparator comparator = createComparator();
     comparator.setType(type);
     createIndexNoQuestionsAsked(comparator, defIndexName, FSIndex.BAG_INDEX);
     assert this.indexArray[typeCode].size() == 1;
     //add the FS to the bag index
     
((IndexIteratorCachePair)this.indexArray[typeCode].get(0)).index.insert(fsRef);
   }
 }


So far this seems to be working.

One potential issue is that this would add new indexes after the
IndexRepository has been "committed".  However, the
IndexRepository.commit() method currently only does this:
 public void commit() {
   // Will create the default type order if it doesn't exist at this point.
   getDefaultTypeOrder();
   this.locked = true;
 }

So it doesn't seem like there is anything being done on commit that
would break if I add new indexes later.

What do you think?

-Adam