通过dotLucene实现增量索引

不知道以前, 觉得很难. 实现以后觉得太容易了.

主要是初始化IndexWriter的时候, 不初始化新的, 而是先读Search目录. 附上源代码.
注释了的是我以前的老代码, 那时候不能进行增量.

using System;

using Lucene.Net.Documents;
using Lucene.Net.Index;
using Lucene.Net.Store;
using Lucene.Net.Analysis.Cn;
using Lucene.Net.Analysis.CJK;

namespace SearchEnginer {
    public sealed class Indexer : IDisposable {
    //    Directory dir = null;
        IndexWriter writer = null;

        private Indexer() {
        }

        public Indexer (string physicalPath, bool create, bool useTempDirectory) {
        //    if(useTempDirectory) {
        //        physicalPath = System.IO.Path.Combine(physicalPath, "tempindex");
        //    }

            ChineseAnalyzer analyzer = new ChineseAnalyzer();
        //    dir = FSDirectory.GetDirectory(physicalPath, create);

            writer = GetWriter(physicalPath);//new IndexWriter(dir, analyzer, create);
            writer.mergeFactor = 15;
        }

        public void AddDocument (Document doc) {
            writer.AddDocument(doc);
        }

        private IndexWriter GetWriter(string physicalPath) {
            IndexWriter indexWriter = null;
            
            string segmentFile = System.IO.Path.Combine(physicalPath, "segments");

            if ( System.IO.File.Exists(segmentFile) )
                indexWriter = new IndexWriter(physicalPath, new Lucene.Net.Analysis.Cn.ChineseAnalyzer(), false);
            else
                indexWriter = new IndexWriter(physicalPath, new Lucene.Net.Analysis.Cn.ChineseAnalyzer(), true);

            return indexWriter;
        }

        public void Close() {
            if (!disposed) {
            //    dir.Close();
                writer.Optimize();
                writer.Close();
                disposed = true;
            }
        }

        private bool disposed = false;

        public void Dispose() {
            Close();
        }
    }
}