PERFORMANCE: Eliminated several calls to FirstOrDefault(), LastOrDefa…

…ult(), Skip(), First(), and Last() (see #261)
apache · Jul 29, 2020 · 61bd539 · 61bd539
1 parent 17c12be
commit 61bd539
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Showing 6 changed files with 18 additions and 18 deletions.
diff --git a/src/Lucene.Net.Analysis.Kuromoji/JapaneseTokenizer.cs b/src/Lucene.Net.Analysis.Kuromoji/JapaneseTokenizer.cs
@@ -10,7 +10,6 @@
 using System.Diagnostics;
 using System.Globalization;
 using System.IO;
-using System.Linq;
 using System.Threading;
 using Console = Lucene.Net.Util.SystemConsole;
 
@@ -379,7 +378,7 @@ public override bool IncrementToken()
                 Parse();
             }
 
-            Token token = pending.LastOrDefault();
+            Token token = pending[pending.Count - 1]; // LUCENENET: The above loop ensures we don't get here unless we have at least 1 item
             if (token != null)
             {
                 pending.Remove(token);

diff --git a/src/Lucene.Net.Analysis.Phonetic/Language/Bm/PhoneticEngine.cs b/src/Lucene.Net.Analysis.Phonetic/Language/Bm/PhoneticEngine.cs
@@ -5,12 +5,10 @@
 using Lucene.Net.Util;
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using System.Text.RegularExpressions;
 using JCG = J2N.Collections.Generic;
 
-
 namespace Lucene.Net.Analysis.Phonetic.Language.Bm
 {
     /*
@@ -483,7 +481,7 @@ public virtual string Encode(string input, LanguageSet languageSet)
             {
                 // not a multi-word name
                 //input = words.iterator().next();
-                input = words.FirstOrDefault();
+                input = words[0];
             }
             else
             {

diff --git a/src/Lucene.Net.Benchmark/Quality/Utils/DocNameExtractor.cs b/src/Lucene.Net.Benchmark/Quality/Utils/DocNameExtractor.cs
@@ -3,7 +3,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 
 namespace Lucene.Net.Benchmarks.Quality.Utils
 {
@@ -52,7 +51,7 @@ public virtual string DocName(IndexSearcher searcher, int docid)
             IList<string> name = new List<string>();
             searcher.IndexReader.Document(docid, new StoredFieldVisitorAnonymousHelper(this, name));
 
-            return name.FirstOrDefault();
+            return name.Count > 0 ? name[0] : null;
         }
 
         private class StoredFieldVisitorAnonymousHelper : StoredFieldVisitor

diff --git a/src/Lucene.Net.Grouping/SearchGroup.cs b/src/Lucene.Net.Grouping/SearchGroup.cs
@@ -4,7 +4,6 @@
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
-using System.Reflection;
 using JCG = J2N.Collections.Generic;
 
 namespace Lucene.Net.Search.Grouping
@@ -390,7 +389,7 @@ private void UpdateNextGroup(int topN, ShardIter<T> shard)
                 // Prune un-competitive groups:
                 while (queue.Count > topN)
                 {
-                    MergedGroup<T> group = queue.Last();
+                    MergedGroup<T> group = queue.Max;
                     queue.Remove(group);
                     //System.out.println("PRUNE: " + group);
                     group.IsInQueue = false;
@@ -421,7 +420,7 @@ public virtual ICollection<SearchGroup<T>> Merge(IList<IEnumerable<ISearchGroup<
 
                 while (queue.Count != 0)
                 {
-                    MergedGroup<T> group = queue.First();
+                    MergedGroup<T> group = queue.Min;
                     queue.Remove(group);
                     group.IsProcessed = true;
                     //System.out.println("  pop: shards=" + group.shards + " group=" + (group.groupValue == null ? "null" : (((BytesRef) group.groupValue).utf8ToString())) + " sortValues=" + Arrays.toString(group.topValues));

diff --git a/src/Lucene.Net.QueryParser/Surround/Query/NotQuery.cs b/src/Lucene.Net.QueryParser/Surround/Query/NotQuery.cs
@@ -1,6 +1,5 @@
 using Lucene.Net.Search;
 using System.Collections.Generic;
-using System.Linq;
 
 namespace Lucene.Net.QueryParsers.Surround.Query
 {
@@ -34,12 +33,19 @@ public NotQuery(IList<SrndQuery> queries, string opName)
         public override Search.Query MakeLuceneQueryFieldNoBoost(string fieldName, BasicQueryFactory qf)
         {
             var luceneSubQueries = MakeLuceneSubQueriesField(fieldName, qf);
-            BooleanQuery bq = new BooleanQuery();
-            bq.Add(luceneSubQueries.FirstOrDefault(), Occur.MUST);
+            BooleanQuery bq = new BooleanQuery
+            {
+                { luceneSubQueries.Count > 0 ? luceneSubQueries[0] : null, Occur.MUST }
+            };
+
+            // LUCENENET: SubList() is slow, so we do an array copy operation instead
+            var luceneSubQueriesArray = new Search.Query[luceneSubQueries.Count - 1];
+            for (int i = 1, j = 0; i < luceneSubQueries.Count; i++, j++)
+                luceneSubQueriesArray[j] = luceneSubQueries[i];
+
             SrndBooleanQuery.AddQueriesToBoolean(bq,
-                // FIXME: do not allow weights on prohibited subqueries.
-                    //luceneSubQueries.subList(1, luceneSubQueries.size()),
-                    luceneSubQueries.Skip(1).ToList(),
+                    // FIXME: do not allow weights on prohibited subqueries.
+                    luceneSubQueriesArray,
                 // later subqueries: not required, prohibited
                     Occur.MUST_NOT);
             return bq;

diff --git a/src/Lucene.Net/Store/LockStressTest.cs b/src/Lucene.Net/Store/LockStressTest.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Globalization;
 using System.IO;
-using System.Linq;
 using System.Net;
 using System.Net.Sockets;
 using System.Threading;
@@ -78,7 +77,7 @@ public static void Main(string[] args)
             int count = Convert.ToInt32(args[arg++], CultureInfo.InvariantCulture);
 
             IPAddress[] addresses = Dns.GetHostAddressesAsync(verifierHost).Result;
-            IPAddress addr = addresses.FirstOrDefault();
+            IPAddress addr = addresses.Length > 0 ? addresses[0] : null;
 
             Type c;
             try