private static void CollectFirstAndLastTermMatches(
IndexReader indexReader,
string fieldToSearch,
List <Term> firstTermMatches,
List <Term> lastTermMatches,
string firstTerm,
string lastTerm)
{
bool isFirstTermPunctuation = (firstTerm.Length == 1 && LuceneHelper.IsPunctuation(firstTerm.First()));
bool isLastTermPunctuation = (lastTerm.Length == 1 && LuceneHelper.IsPunctuation(lastTerm.First()));
//punctuation characters are always by themselves, no need to check for terms starting/ending with one!
if (isFirstTermPunctuation && isLastTermPunctuation)
{
return;
}
// !! reader.Terms(new Term(..., ...)) does not as expected, so check every term !!
var termEnum = indexReader.Terms();
HashSet <string> addedFirstTerms = new HashSet <string>();
HashSet <string> addedLastTerms = new HashSet <string>();
//Use actions for adding first/last terms
//This will yield better performance!
//Since there are thousands of terms in the index,
//performing the string operations for first and last term on all of them,
//even though we already know they're not going to match (because punctuations stand alone),
//will waste a lot of time!
Action <Term> addFirstTermAction = (curTerm) =>
{
if (addedFirstTerms.Contains(curTerm.Text) || !curTerm.Text.EndsWith(firstTerm))
{
return;
}
firstTermMatches.Add(curTerm);
addedFirstTerms.Add(curTerm.Text);
};
Action <Term> addLastTermAction = (curTerm) =>
{
if (addedLastTerms.Contains(curTerm.Text) || !curTerm.Text.StartsWith(lastTerm))
{
return;
}
lastTermMatches.Add(curTerm);
addedLastTerms.Add(curTerm.Text);
};
Action <Term> collectTermsAction = null;
if (!isFirstTermPunctuation)
{
collectTermsAction += addFirstTermAction;
}
if (!isLastTermPunctuation)
{
collectTermsAction += addLastTermAction;
}
while (termEnum.Next())
{
var curTerm = termEnum.Term;
//skip wrong fields
if (curTerm.Field != fieldToSearch)
{
continue;
}
collectTermsAction(curTerm);
}
}
private Query BuildMatchAnywhereQuery(IndexReader indexReader, string expandedSearchString, bool matchCase)
{
List <string> searchTerms = null;
string adjustedSearchString = expandedSearchString;
string fieldToSearch = Constants.IndexFields.Content;
if (!matchCase)
{
fieldToSearch = Constants.IndexFields.ContentCaseInsensitive;
adjustedSearchString = adjustedSearchString.ToLower();
}
searchTerms = adjustedSearchString.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).ToList();
bool onlyOneTerm = searchTerms.Count == 1;
var firstTerm = searchTerms.FirstOrDefault();
var lastTerm = searchTerms.LastOrDefault();
Query contentQuery = null;
if (onlyOneTerm)
{
bool isFirstTermPunctuation = (firstTerm.Length == 1 && LuceneHelper.IsPunctuation(firstTerm.First()));
if (isFirstTermPunctuation)
{
contentQuery = new TermQuery(new Term(fieldToSearch, firstTerm));
}
else
{
contentQuery = new WildcardQuery(new Term(fieldToSearch, "*" + firstTerm + "*"));
}
}
else
{
MultiPhraseQuery phraseQuery = new MultiPhraseQuery();
List <Term> firstTermMatches = new List <Term>();
List <Term> lastTermMatches = new List <Term>();
CollectFirstAndLastTermMatches(indexReader, fieldToSearch, firstTermMatches, lastTermMatches, firstTerm, lastTerm);
if (firstTermMatches.Count > 0)
{
phraseQuery.Add(firstTermMatches.ToArray());
}
bool includeFirstTerm = firstTermMatches.Count == 0;
bool includeLastTerm = lastTermMatches.Count == 0;
int startIndex = includeFirstTerm ? 0 : 1;
int endIndex = searchTerms.Count - (includeLastTerm ? 0 : 1);
for (int i = startIndex; i < endIndex; i++)
{
phraseQuery.Add(new Term(fieldToSearch, searchTerms[i]));
}
if (lastTermMatches.Count > 0)
{
phraseQuery.Add(lastTermMatches.ToArray());
}
contentQuery = phraseQuery;
}
return(contentQuery);
}
