Package org.apache.hadoop.hbase.filter

Class PageFilter

java.lang.Object
org.apache.hadoop.hbase.filter.Filter
org.apache.hadoop.hbase.filter.FilterBase
org.apache.hadoop.hbase.filter.PageFilter
@Public public class PageFilter extends FilterBase
Implementation of Filter interface that limits results to a specific page size. It terminates scanning once the number of filter-passed rows is > the given page size.

Note that this filter cannot guarantee that the number of results returned to a client are <= page size. This is because the filter is applied separately on different region servers. It does however optimize the scan of individual HRegions by making sure that the page size is never exceeded locally.

  • Field Details

  • Constructor Details

    • PageFilter

      public PageFilter(long pageSize)
      Constructor that takes a maximum page size.
      Parameters:
      pageSize - Maximum result size.

  • Method Details

    • getPageSize

      public long getPageSize()

    • 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 ignored) 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:
      ignored - 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:

    • filterAllRemaining

      public boolean filterAllRemaining()
      Description copied from class: FilterBase
      Filters that never filter all remaining can inherit this implementation that never stops the filter early. If this returns true, the scan will terminate. Concrete implementers can signal a failure condition in their code by throwing an IOException.
      Overrides:
      filterAllRemaining in class FilterBase
      Returns:
      true to end scan, false to continue.

    • filterRow

      public boolean filterRow()
      Description copied from class: FilterBase
      Filters that never filter by rows based on previously gathered state from Filter.filterCell(Cell) can inherit this implementation that never filters a row. 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.
      Overrides:
      filterRow in class FilterBase
      Returns:
      true to exclude row, false to include row.

    • hasFilterRow

      public boolean hasFilterRow()
      Description copied from class: FilterBase
      Filters that never filter by modifying the returned List of Cells can inherit this implementation that does nothing. Primarily used to check for conflicts with scans(such as scans that do not read a full row at a time).
      Overrides:
      hasFilterRow in class FilterBase
      Returns:
      True if this filter actively uses filterRowCells(List) or filterRow().

    • 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 PageFilter parseFrom(byte[] pbBytes) throws DeserializationException
      Parse a serialized representation of PageFilter
      Parameters:
      pbBytes - A pb serialized PageFilter instance
      Returns:
      An instance of PageFilter 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.

    • 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