hbase 源代码解析（21） 自定义过滤器

filter 需要实现Filter 或者继承FilterBase

@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class Filter {
//返回码
  public enum ReturnCode {
    INCLUDE, //结果中包含着一样
    INCLUDE_AND_NEXT_COL, //包含着这样一行，跳到下一行比较
    SKIP,  //跳到下一个keyvalue 并进行处理
    NEXT_COL, //跳过当前一col
    NEXT_ROW,  //跳过当前一行
    SEEK_NEXT_USING_HINT,  //跳到下一个满足地方，需要调用getNextKeyHint（）
}
  protected transient boolean reversed;
  abstract public void reset() throws IOException;
//判断行健是否满足，不满足可以跳过，避免其他检查：比如前缀过滤器
  abstract public boolean filterRowKey(byte[] buffer, int offset, int length) throws IOException;
//这个过滤器可以提前结束
  abstract public boolean filterAllRemaining() throws IOException;
//对cell处理，
  abstract public ReturnCode filterKeyValue(final Cell v) throws IOException;
  abstract public Cell transformCell(final Cell v) throws IOException;
  @Deprecated // use Cell transformCell(final Cell)
  abstract public KeyValue transform(final KeyValue currentKV) throws IOException;
//经过前面处理后，如果还有数据，将对当前行一起处理， 比如依赖过去器
  abstract public void filterRowCells(List<Cell> kvs) throws IOException;
  abstract public boolean hasFilterRow()；
//经过这么多流程如果还有数据，会去检查一下数据的要求。比如pagefilter 是否已经够一页了
abstract public boolean filterRow() throws IOException;
  @Deprecated
  abstract public KeyValue getNextKeyHint(final KeyValue currentKV) throws IOException;
  abstract public Cell getNextCellHint(final Cell currentKV) throws IOException;
  abstract public boolean isFamilyEssential(byte[] name) throws IOException;
  abstract public byte[] toByteArray() throws IOException;
  public static Filter parseFrom(final byte [] pbBytes) throws DeserializationException {
    throw new DeserializationException(
      "parseFrom called on base Filter, but should be called on derived type");
  }
  abstract boolean areSerializedFieldsEqual(Filter other);
  public void setReversed(boolean reversed) {
    this.reversed = reversed;
  }
  public boolean isReversed() {
    return this.reversed;
  }
}

流程如下：

 

scan，或者get是调用的入口

基本流程就是下面 一样，但是没有看到fiterKeyValue，如果你们找到了，告诉我一声。

   private boolean nextInternal(List<Cell> results, ScannerContext scannerContext)
        throws IOException {
  
   
      while (true) {
    
        boolean stopRow = isStopRow(currentRow, offset, length);
       
        boolean hasFilterRow = this.filter != null && this.filter.hasFilterRow();
      
        if (hasFilterRow) {
          if (LOG.isTraceEnabled()) {
            LOG.trace("filter#hasFilterRow is true which prevents partial results from being "
                + " formed. Changing scope of limits that may create partials");
          }
          scannerContext.setSizeLimitScope(LimitScope.BETWEEN_ROWS);
          scannerContext.setTimeLimitScope(LimitScope.BETWEEN_ROWS);
        }
          if (filterRowKey(currentRow, offset, length)) {
            incrementCountOfRowsFilteredMetric(scannerContext);
            // early check, see HBASE-16296
       //filterAllRemaining 实际调用
            if (isFilterDoneInternal()) {
              return scannerContext.setScannerState(NextState.NO_MORE_VALUES).hasMoreValues();
            }
            incrementCountOfRowsScannedMetric(scannerContext);
//里面会调用filter.reset();
            boolean moreRows = nextRow(scannerContext, currentRow, offset, length);
            if (!moreRows) {
              return scannerContext.setScannerState(NextState.NO_MORE_VALUES).hasMoreValues();
            }
            results.clear();
            continue;
          }
          populateResult(results, this.storeHeap, scannerContext, currentRow, offset, length);
          Cell nextKv = this.storeHeap.peek();
          stopRow = nextKv == null ||
              isStopRow(nextKv.getRowArray(), nextKv.getRowOffset(), nextKv.getRowLength());
        
          final boolean isEmptyRow = results.isEmpty();
 FilterWrapper.FilterRowRetCode ret = FilterWrapper.FilterRowRetCode.NOT_CALLED;
          if (hasFilterRow) {
//会调用filterRowCells（List） 和filterRowCells（cell）
            ret = filter.filterRowCellsWithRet(results);
            long timeProgress = scannerContext.getTimeProgress();
            if (scannerContext.getKeepProgress()) {
              scannerContext.setProgress(initialBatchProgress, initialSizeProgress,
                initialTimeProgress);
            } else {
              scannerContext.clearProgress();
            }
            scannerContext.setTimeProgress(timeProgress);
            scannerContext.incrementBatchProgress(results.size());
            for (Cell cell : results) {
              scannerContext.incrementSizeProgress(CellUtil.estimatedHeapSizeOfWithoutTags(cell));
            }
          }
          if (isEmptyRow || ret == FilterWrapper.FilterRowRetCode.EXCLUDE || filterRow()) {
            incrementCountOfRowsFilteredMetric(scannerContext);
            results.clear();
            boolean moreRows = nextRow(scannerContext, currentRow, offset, length);
            if (!moreRows) {
              return scannerContext.setScannerState(NextState.NO_MORE_VALUES).hasMoreValues();
            }
             if (!stopRow) continue;
            return scannerContext.setScannerState(NextState.NO_MORE_VALUES).hasMoreValues();
          }
          if (this.joinedHeap != null) {
            boolean mayHaveData = joinedHeapMayHaveData(currentRow, offset, length);
            if (mayHaveData) {
              joinedContinuationRow = current;
              populateFromJoinedHeap(results, scannerContext);
              if (scannerContext.checkAnyLimitReached(LimitScope.BETWEEN_CELLS)) {
                return true;
              }
            }
          }
        } else {
          populateFromJoinedHeap(results, scannerContext);
          if (scannerContext.checkAnyLimitReached(LimitScope.BETWEEN_CELLS)) {
            return true;
          }
        }
    
        if (stopRow) {
          return scannerContext.setScannerState(NextState.NO_MORE_VALUES).hasMoreValues();
        } else {
          return scannerContext.setScannerState(NextState.MORE_VALUES).hasMoreValues();
        }
      }
    }

就这样。

自定义完成后，打成jar ，需要export export HBASE_CLAPSS 

或者将jar 放到hbase 的安装目录的lib下面，重启hbase