Lucene.Net.Index.SegmentInfos.GetLastCommitGeneration C# (CSharp) Метод

        public static long GetLastCommitGeneration(Directory directory)
        {
            try
            {
                return GetLastCommitGeneration(directory.ListAll());
            }
            catch (NoSuchDirectoryException)
            {
                return -1;
            }
        }

        public virtual void TestKeepLastNDeletionPolicyWithCreates()
        {
            const int N = 10;

            for (int pass = 0; pass < 2; pass++)
            {
                bool useCompoundFile = (pass % 2) != 0;

                Directory         dir  = NewDirectory();
                IndexWriterConfig conf = (IndexWriterConfig)NewIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(Random)).SetOpenMode(OpenMode.CREATE).SetIndexDeletionPolicy(new KeepLastNDeletionPolicy(this, N)).SetMaxBufferedDocs(10);
                MergePolicy       mp   = conf.MergePolicy;
                mp.NoCFSRatio = useCompoundFile ? 1.0 : 0.0;
                IndexWriter             writer = new IndexWriter(dir, conf);
                KeepLastNDeletionPolicy policy = (KeepLastNDeletionPolicy)writer.Config.IndexDeletionPolicy;
                writer.Dispose();
                Term  searchTerm = new Term("content", "aaa");
                Query query      = new TermQuery(searchTerm);

                for (int i = 0; i < N + 1; i++)
                {
                    conf          = (IndexWriterConfig)NewIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(Random)).SetOpenMode(OpenMode.APPEND).SetIndexDeletionPolicy(policy).SetMaxBufferedDocs(10);
                    mp            = conf.MergePolicy;
                    mp.NoCFSRatio = useCompoundFile ? 1.0 : 0.0;
                    writer        = new IndexWriter(dir, conf);
                    policy        = (KeepLastNDeletionPolicy)writer.Config.IndexDeletionPolicy;
                    for (int j = 0; j < 17; j++)
                    {
                        AddDocWithID(writer, i * (N + 1) + j);
                    }
                    // this is a commit
                    writer.Dispose();
                    conf   = (new IndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(Random))).SetIndexDeletionPolicy(policy).SetMergePolicy(NoMergePolicy.COMPOUND_FILES);
                    writer = new IndexWriter(dir, conf);
                    policy = (KeepLastNDeletionPolicy)writer.Config.IndexDeletionPolicy;
                    writer.DeleteDocuments(new Term("id", "" + (i * (N + 1) + 3)));
                    // this is a commit
                    writer.Dispose();
                    IndexReader   reader   = DirectoryReader.Open(dir);
                    IndexSearcher searcher = NewSearcher(reader);
                    ScoreDoc[]    hits     = searcher.Search(query, null, 1000).ScoreDocs;
                    Assert.AreEqual(16, hits.Length);
                    reader.Dispose();

                    writer = new IndexWriter(dir, NewIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(Random)).SetOpenMode(OpenMode.CREATE).SetIndexDeletionPolicy(policy));
                    policy = (KeepLastNDeletionPolicy)writer.Config.IndexDeletionPolicy;
                    // this will not commit: there are no changes
                    // pending because we opened for "create":
                    writer.Dispose();
                }

                Assert.AreEqual(3 * (N + 1) + 1, policy.NumOnInit);
                Assert.AreEqual(3 * (N + 1) + 1, policy.NumOnCommit);

                IndexReader   rwReader  = DirectoryReader.Open(dir);
                IndexSearcher searcher_ = NewSearcher(rwReader);
                ScoreDoc[]    hits_     = searcher_.Search(query, null, 1000).ScoreDocs;
                Assert.AreEqual(0, hits_.Length);

                // Simplistic check: just verify only the past N segments_N's still
                // exist, and, I can open a reader on each:
                long gen = SegmentInfos.GetLastCommitGeneration(dir);

                dir.DeleteFile(IndexFileNames.SEGMENTS_GEN);
                int expectedCount = 0;

                rwReader.Dispose();

                for (int i = 0; i < N + 1; i++)
                {
                    try
                    {
                        IndexReader reader = DirectoryReader.Open(dir);

                        // Work backwards in commits on what the expected
                        // count should be.
                        searcher_ = NewSearcher(reader);
                        hits_     = searcher_.Search(query, null, 1000).ScoreDocs;
                        Assert.AreEqual(expectedCount, hits_.Length);
                        if (expectedCount == 0)
                        {
                            expectedCount = 16;
                        }
                        else if (expectedCount == 16)
                        {
                            expectedCount = 17;
                        }
                        else if (expectedCount == 17)
                        {
                            expectedCount = 0;
                        }
                        reader.Dispose();
                        if (i == N)
                        {
                            Assert.Fail("should have failed on commits before last " + N);
                        }
                    }
                    catch (IOException /*e*/)
                    {
                        if (i != N)
                        {
                            throw; // LUCENENET: CA2200: Rethrow to preserve stack details (https://docs.microsoft.com/en-us/visualstudio/code-quality/ca2200-rethrow-to-preserve-stack-details)
                        }
                    }
                    if (i < N)
                    {
                        dir.DeleteFile(IndexFileNames.FileNameFromGeneration(IndexFileNames.SEGMENTS, "", gen));
                    }
                    gen--;
                }

                dir.Dispose();
            }
        }