Make OkapiIndex the default index.

ZCTextIndex has grown a new argument with a default value that can be
used to specify an Index class to use.  The default is OkapiIndex.Index.

There is a little kludge to make the test succeed.
testZCTestIndex.IndexTests uses the Index.Index tests instead of
OkapiIndex.Index.  Tim will probably fix this.

lib/python/Products/ZCTextIndex/ZCTextIndex.py

@@ -27,7 +27,7 @@ from Products.PluginIndexes.common.PluggableIndex \
      import PluggableIndexInterface
 from Products.PluginIndexes.common.util import parseIndexRequest
 
-from Products.ZCTextIndex.Index import Index
+from Products.ZCTextIndex.OkapiIndex import Index
 from Products.ZCTextIndex.ILexicon import ILexicon
 from Products.ZCTextIndex.Lexicon \
      import Lexicon, Splitter, CaseNormalizer, StopWordRemover
@@ -47,7 +47,7 @@ class ZCTextIndex(Persistent, Acquisition.Implicit, SimpleItem):
     
     query_options = ['query']
 
-    def __init__(self, id, extra, caller):
+    def __init__(self, id, extra, caller, index_factory=Index):
         self.id = id
         self._fieldname = extra.doc_attr
         lexicon = getattr(caller, extra.lexicon_id, None)
@@ -61,7 +61,7 @@ class ZCTextIndex(Persistent, Acquisition.Implicit, SimpleItem):
                 % lexicon.getId()
 
         self.lexicon = lexicon
-        self.index = Index(self.lexicon)
+        self.index = index_factory(self.lexicon)
         self.parser = QueryParser()
         
     ## Pluggable Index APIs ##

lib/python/Products/ZCTextIndex/tests/testZCTextIndex.py

 from Products.ZCTextIndex.ZCTextIndex import ZCTextIndex
 from Products.ZCTextIndex.tests \
      import testIndex, testQueryEngine, testQueryParser
-from Products.ZCTextIndex.Index import scaled_int, SCALE_FACTOR
+from Products.ZCTextIndex.Index import scaled_int, SCALE_FACTOR, Index
 from Products.ZCTextIndex.Lexicon import Lexicon, Splitter
 from Products.ZCTextIndex.Lexicon import CaseNormalizer, StopWordRemover
 
@@ -35,7 +35,7 @@ class IndexTests(testIndex.IndexTest):
         extra.lexicon_id = 'lexicon'
         caller = LexiconHolder(Lexicon(Splitter(), CaseNormalizer(),
                                StopWordRemover()))
-        self.zc_index = ZCTextIndex('name', extra, caller)
+        self.zc_index = ZCTextIndex('name', extra, caller, Index)
         self.index = self.zc_index.index
         self.lexicon = self.zc_index.lexicon