Package org.apache.hadoop.hbase.filter

Class FilterWrapper

java.lang.Object
org.apache.hadoop.hbase.filter.Filter
org.apache.hadoop.hbase.filter.FilterWrapper
@Private public final class FilterWrapper extends Filter
This is a Filter wrapper class which is used in the server side. Some filter related hooks can be defined in this wrapper. The only way to create a FilterWrapper instance is passing a client side Filter instance through Scan.getFilter().

  • Field Details

  • Constructor Details

  • Method Details

    • toByteArray

      public byte[] toByteArray() throws IOException
      Returns The filter serialized using pb
      Specified by:
      toByteArray in class Filter
      Returns:
      The filter serialized using pb
      Throws:
      IOException - in case an I/O or an filter specific failure needs to be signaled.

    • parseFrom

      public static FilterWrapper parseFrom(byte[] pbBytes) throws DeserializationException
      Parameters:
      pbBytes - A pb serialized FilterWrapper instance
      Returns:
      An instance of FilterWrapper made from bytes
      Throws:
      DeserializationException
      See Also:

    • reset

      public void reset() throws IOException
      Description copied from class: Filter
      Reset the state of the filter between rows. Concrete implementers can signal a failure condition in their code by throwing an IOException.
      Specified by:
      reset in class Filter
      Throws:
      IOException - in case an I/O or an filter specific failure needs to be signaled.

    • filterAllRemaining

      public boolean filterAllRemaining() throws IOException
      Description copied from class: Filter
      If this returns true, the scan will terminate. Concrete implementers can signal a failure condition in their code by throwing an IOException.
      Specified by:
      filterAllRemaining in class Filter
      Returns:
      true to end scan, false to continue.
      Throws:
      IOException - in case an I/O or an filter specific failure needs to be signaled.

    • filterRow

      public boolean filterRow() throws IOException
      Description copied from class: Filter
      Last chance to veto row based on previous Filter.filterCell(Cell) calls. The filter needs to retain state then return a particular value for this call if they wish to exclude a row if a certain column is missing (for example). Concrete implementers can signal a failure condition in their code by throwing an IOException.
      Specified by:
      filterRow in class Filter
      Returns:
      true to exclude row, false to include row.
      Throws:
      IOException - in case an I/O or an filter specific failure needs to be signaled.

    • getNextCellHint

      public Cell getNextCellHint(Cell currentCell) throws IOException
      Description copied from class: Filter
      If the filter returns the match code SEEK_NEXT_USING_HINT, then it should also tell which is the next key it must seek to. After receiving the match code SEEK_NEXT_USING_HINT, the QueryMatcher would call this function to find out which key it must next seek to. Concrete implementers can signal a failure condition in their code by throwing an IOException. NOTICE: Filter will be evaluate at server side so the returned Cell must be an ExtendedCell, although it is marked as IA.Private.
      Specified by:
      getNextCellHint in class Filter
      Returns:
      KeyValue which must be next seeked. return null if the filter is not sure which key to seek to next.
      Throws:
      IOException - in case an I/O or an filter specific failure needs to be signaled.

    • getHintForRejectedRow

      public Cell getHintForRejectedRow(Cell firstRowCell) throws IOException
      Delegates to the wrapped filter's Filter.getHintForRejectedRow(Cell) so that the scan pipeline can seek directly past a rejected row rather than iterating cell-by-cell via nextRow(). Provides a seek hint to bypass row-by-row scanning after Filter.filterRowKey(Cell) rejects a row. When filterRowKey returns true the scan pipeline would normally iterate through every remaining cell in the rejected row one-by-one (via nextRow()) before moving on. If the filter can determine a better forward position — for example, the next range boundary in a MultiRowRangeFilter — it should return that target cell here, allowing the scanner to seek directly past the unwanted rows.

      Contract:

      • Only called after Filter.filterRowKey(Cell) has returned true for the same firstRowCell.
      • Implementations may use state that was set during Filter.filterRowKey(Cell) (e.g. an updated range pointer), but must not invoke Filter.filterCell(Cell) logic — the caller guarantees that filterCell has not been called for this row.
      • The returned Cell, if non-null, must be an ExtendedCell because filters are evaluated on the server side.
      • Returning null (the default) falls through to the existing nextRow() behaviour, preserving full backward compatibility.
      • For reversed scans (Scan.isReversed()), the hint must point to a smaller row key (earlier in reverse-scan direction). The scanner validates hint direction and falls back to nextRow() if the hint does not advance in the scan direction.
      • Composite filter limitation: FilterList, SkipFilter, and WhileMatchFilter do not currently delegate this method to wrapped sub-filters. Hints from filters used inside these wrappers will be silently ignored.
      Overrides:
      getHintForRejectedRow in class Filter
      Parameters:
      firstRowCell - the first cell encountered in the rejected row; contains the row key that was passed to filterRowKey
      Returns:
      a Cell representing the earliest position the scanner should seek to, or null if this filter cannot provide a better position than a sequential skip
      Throws:
      IOException - in case an I/O or filter-specific failure needs to be signaled
      See Also:

    • getSkipHint

      public Cell getSkipHint(Cell skippedCell) throws IOException
      Delegates to the wrapped filter's Filter.getSkipHint(Cell) so that the scan pipeline can seek ahead when a cell is structurally skipped before filterCell is reached. Provides a seek hint for cells that are structurally skipped by the scan pipeline before Filter.filterCell(Cell) is ever reached. The pipeline short-circuits on several criteria — time-range mismatch, column-set exclusion, and version-limit exhaustion — and in each case the filter is bypassed entirely. When an implementation can compute a meaningful forward position purely from the cell's coordinates (without needing the filterCell call sequence), it should return that position here so the scanner can seek ahead instead of advancing one cell at a time.

      Contract:

      • May be called for cells that have never been passed to Filter.filterCell(Cell).
      • Implementations must not modify any filter state; this method is treated as logically stateless. Only filters whose hint computation is based solely on immutable configuration (e.g. a fixed column range or a fuzzy-row pattern) should override this.
      • The returned Cell, if non-null, must be an ExtendedCell because filters are evaluated on the server side.
      • Returning null (the default) falls through to the existing structural skip/seek behaviour, preserving full backward compatibility.
      • For reversed scans, the returned cell must have a smaller row key (i.e., earlier in reverse-scan direction) than the skippedCell. Hints that do not advance in the scan direction are silently ignored.
      • Composite filter limitation: FilterList, SkipFilter, and WhileMatchFilter do not currently delegate this method to wrapped sub-filters. Hints from filters used inside these wrappers will be silently ignored.
      Overrides:
      getSkipHint in class Filter
      Parameters:
      skippedCell - the cell that was rejected by the time-range, column, or version gate before filterCell could be consulted
      Returns:
      a Cell representing the earliest position the scanner should seek to, or null if this filter cannot provide a better position than the structural hint
      Throws:
      IOException - in case an I/O or filter-specific failure needs to be signaled
      See Also:

    • filterRowKey

      public boolean filterRowKey(Cell cell) throws IOException
      Description copied from class: Filter
      Filters a row based on the row key. If this returns true, the entire row will be excluded. If false, each KeyValue in the row will be passed to Filter.filterCell(Cell) below. If Filter.filterAllRemaining() returns true, then Filter.filterRowKey(Cell) should also return true. Concrete implementers can signal a failure condition in their code by throwing an IOException.
      Specified by:
      filterRowKey in class Filter
      Parameters:
      cell - The first cell coming in the new row
      Returns:
      true, remove entire row, false, include the row (maybe).
      Throws:
      IOException - in case an I/O or an filter specific failure needs to be signaled.

    • filterCell

      public Filter.ReturnCode filterCell(Cell c) throws IOException
      Description copied from class: Filter
      A way to filter based on the column family, column qualifier and/or the column value. Return code is described below. This allows filters to filter only certain number of columns, then terminate without matching ever column. If filterRowKey returns true, filterCell needs to be consistent with it. filterCell can assume that filterRowKey has already been called for the row. If your filter returns ReturnCode.NEXT_ROW, it should return ReturnCode.NEXT_ROW until Filter.reset() is called just in case the caller calls for the next row. Concrete implementers can signal a failure condition in their code by throwing an IOException.
      Overrides:
      filterCell in class Filter
      Parameters:
      c - the Cell in question
      Returns:
      code as described below
      Throws:
      IOException - in case an I/O or an filter specific failure needs to be signaled.
      See Also:

    • transformCell

      public Cell transformCell(Cell v) throws IOException
      Description copied from class: Filter
      Give the filter a chance to transform the passed Cell. If the Cell is changed a new Cell object must be returned.

      NOTICE: Filter will be evaluate at server side so the returned Cell must be an ExtendedCell, although it is marked as IA.Private.

      Specified by:
      transformCell in class Filter
      Parameters:
      v - the Cell in question
      Returns:
      the changed Cell
      Throws:
      IOException - in case an I/O or an filter specific failure needs to be signaled.
      See Also:

    • hasFilterRow

      public boolean hasFilterRow()
      Description copied from class: Filter
      Primarily used to check for conflicts with scans(such as scans that do not read a full row at a time).
      Specified by:
      hasFilterRow in class Filter
      Returns:
      True if this filter actively uses filterRowCells(List) or filterRow().

    • filterRowCells

      public void filterRowCells(List<Cell> kvs) throws IOException
      Description copied from class: Filter
      Chance to alter the list of Cells to be submitted. Modifications to the list will carry on Concrete implementers can signal a failure condition in their code by throwing an IOException.
      Specified by:
      filterRowCells in class Filter
      Parameters:
      kvs - the list of Cells to be filtered
      Throws:
      IOException - in case an I/O or an filter specific failure needs to be signaled.

    • filterRowCellsWithRet

      public FilterWrapper.FilterRowRetCode filterRowCellsWithRet(List<Cell> kvs) throws IOException
      Throws:
      IOException

    • isFamilyEssential

      public boolean isFamilyEssential(byte[] name) throws IOException
      Description copied from class: Filter
      Check that given column family is essential for filter to check row. Most filters always return true here. But some could have more sophisticated logic which could significantly reduce scanning process by not even touching columns until we are 100% sure that it's data is needed in result. Concrete implementers can signal a failure condition in their code by throwing an IOException.
      Specified by:
      isFamilyEssential in class Filter
      Throws:
      IOException - in case an I/O or an filter specific failure needs to be signaled.

    • areSerializedFieldsEqual

      boolean areSerializedFieldsEqual(Filter o)
      Description copied from class: Filter
      Concrete implementers can signal a failure condition in their code by throwing an IOException.
      Specified by:
      areSerializedFieldsEqual in class Filter
      Parameters:
      o - the other filter to compare with
      Returns:
      true if and only if the fields of the filter that are serialized are equal to the corresponding fields in other. Used for testing.