Package org.apache.hadoop.hbase.filter

Class ColumnPrefixFilter

java.lang.Object
org.apache.hadoop.hbase.filter.Filter
org.apache.hadoop.hbase.filter.FilterBase
org.apache.hadoop.hbase.filter.ColumnPrefixFilter
All Implemented Interfaces:
HintingFilter
@Public public class ColumnPrefixFilter extends FilterBase implements HintingFilter
This filter is used for selecting only those keys with columns that matches a particular prefix. For example, if prefix is 'an', it will pass keys with columns like 'and', 'anti' but not keys with columns like 'ball', 'act'.

  • Field Details

    • prefix

      protected byte[] prefix

  • Constructor Details

  • Method Details

    • getPrefix

      public byte[] getPrefix()

    • 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.
      Overrides:
      filterRowKey in class FilterBase
      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 cell)
      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:
      cell - the Cell in question
      Returns:
      code as described below
      See Also:

    • filterColumn

      public Filter.ReturnCode filterColumn(Cell cell)

    • compareQualifierPart

      private static int compareQualifierPart(Cell cell, int length, byte[] prefix)

    • createFilterFromArguments

      public static Filter createFilterFromArguments(ArrayList<byte[]> filterArguments)

    • toByteArray

      public byte[] toByteArray()
      Returns The filter serialized using pb
      Overrides:
      toByteArray in class FilterBase
      Returns:
      The filter serialized using pb

    • parseFrom

      public static ColumnPrefixFilter parseFrom(byte[] pbBytes) throws DeserializationException
      Parses a serialized representation of the ColumnPrefixFilter
      Parameters:
      pbBytes - A pb serialized ColumnPrefixFilter instance
      Returns:
      An instance of ColumnPrefixFilter made from bytes
      Throws:
      DeserializationException - if an error occurred
      See Also:

    • areSerializedFieldsEqual

      boolean areSerializedFieldsEqual(Filter o)
      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.
      Overrides:
      areSerializedFieldsEqual in class FilterBase
      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.

    • getNextCellHint

      public Cell getNextCellHint(Cell cell)
      Description copied from class: FilterBase
      Filters that are not sure which key must be next seeked to, can inherit this implementation that, by default, returns a null Cell. 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.
      Overrides:
      getNextCellHint in class FilterBase
      Returns:
      KeyValue which must be next seeked. return null if the filter is not sure which key to seek to next.

    • getSkipHint

      public Cell getSkipHint(Cell skippedCell) throws IOException
      Description copied from class: FilterBase
      Filters that cannot provide a structural-skip seek hint can inherit this no-op implementation. Subclasses with purely configuration-driven, stateless hint computation (e.g. a fixed column range or fuzzy-row pattern) may override this to avoid cell-by-cell advancement when the time-range, column, or version gate fires. 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 support: FilterList (both MUST_PASS_ALL and MUST_PASS_ONE), SkipFilter, and WhileMatchFilter delegate this method to their sub-filters and merge the results (maximal step for AND; for OR, the nearest hint is returned only when every non-terminated sub-filter provides one — any null collapses the OR result to null).
      Overrides:
      getSkipHint in class FilterBase
      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:

    • toString

      public String toString()
      Description copied from class: FilterBase
      Return filter's info for debugging and logging purpose.
      Overrides:
      toString in class FilterBase

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object