lucene添加文档源码解析(第三篇)

        IndexWriterConfig config = new IndexWriterConfig(new WhitespaceAnalyzer());
        config.setUseCompoundFile(false);
        config.setMaxBufferedDocs(2);
        IndexWriter writer = new IndexWriter(dir, config);
        //
        FieldType type = new FieldType();
        type.setStored(true);
        type.setTokenized(true);
        type.setIndexOptions(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS);
        type.setStoreTermVectors(true);
        type.setStoreTermVectorPositions(true);
        type.setStoreTermVectorOffsets(true);
        type.freeze();
        //
        Document doc = new Document();
        doc.add(new Field("content", "one", type));
        writer.addDocument(doc);  

  private boolean postUpdate(DocumentsWriterPerThread flushingDWPT, boolean hasEvents) throws IOException, AbortingException {
    // 应用所有的删除信息到已经存在的segment
    hasEvents |= applyAllDeletes(deleteQueue);
    if (flushingDWPT != null) {
      hasEvents |= doFlush(flushingDWPT);
    } else if (config.checkPendingFlushOnUpdate) {
      final DocumentsWriterPerThread nextPendingFlush = flushControl.nextPendingFlush();
      if (nextPendingFlush != null) {
        hasEvents |= doFlush(nextPendingFlush);
      }
    }

    return hasEvents;
  }
  
  private boolean applyAllDeletes(DocumentsWriterDeleteQueue deleteQueue) throws IOException {
    // flushDeletes标志在deleteQueue占用的内存超过IndexWriterConfig.getRAMBufferSizeMB()
    // 时候被设置为true
    if (flushControl.getAndResetApplyAllDeletes()) {
      // 应用全局的删除信息
      if (deleteQueue != null) {
        ticketQueue.addDeletes(deleteQueue);
      }
      // 添加全局删除信息事件
      putEvent(ApplyDeletesEvent.INSTANCE); // apply deletes event forces a purge
      return true;
    }
    return false;
  }

  // 处理事件，比如应用删除信息到已经存在的segment,应用删除信息到刚flush的segment
  private void processEvents(Queue<Event> queue, boolean triggerMerge, boolean forcePurge) throws IOException {
    if (tragedy == null) {
      Event event;
      // 依次取出队列中的事件，处理每一个事件
      while ((event = queue.poll()) != null)  {
        event.process(this, triggerMerge, forcePurge);
      }
    }
  }