org.apache.cassandra.db.filter

## Interface ClusteringIndexFilter

- All Known Implementing Classes:
    AbstractClusteringIndexFilter, ClusteringIndexNamesFilter, ClusteringIndexSliceFilter

      public interface ClusteringIndexFilter

  A filter that selects a subset of the rows of a given partition by using the "clustering index".

  In CQL terms, this correspond to the clustering columns selection and correspond to what the storage engine can do without filtering (and without 2ndary indexes). This does not include the restrictions on non-PK columns which can be found in `RowFilter`.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Interface and Description
    --- | ---
    `static interface` | `ClusteringIndexFilter.InternalDeserializer`
    `static class` | `ClusteringIndexFilter.Kind`
    `static interface` | `ClusteringIndexFilter.Serializer`

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static ClusteringIndexFilter.Serializer` | `serializer`

  - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `UnfilteredRowIterator` | `filterNotIndexed(ColumnFilter columnFilter, UnfilteredRowIterator iterator)` Returns an iterator that only returns the rows of the provided iterator that this filter selects.
    `ClusteringIndexFilter` | `forPaging(ClusteringComparator comparator, Clustering lastReturned, boolean inclusive)` Returns a filter for continuing the paging of this filter given the last returned clustering prefix.
    `Slices` | `getSlices(CFMetaData metadata)`
    `UnfilteredRowIterator` | `getUnfilteredRowIterator(ColumnFilter columnFilter, Partition partition)` Given a partition, returns a row iterator for the rows of this partition that are selected by this filter.
    `boolean` | `isFullyCoveredBy(CachedPartition partition)` Returns whether we can guarantee that a given cached partition contains all the data selected by this filter.
    `boolean` | `isHeadFilter()` Whether this filter selects the head of a partition (i.e.
    `boolean` | `isReversed()` Whether the filter query rows in reversed clustering order or not.
    `ClusteringIndexFilter.Kind` | `kind()`
    `boolean` | `selects(Clustering clustering)` Whether a given row is selected by this filter.
    `boolean` | `selectsAllPartition()` Whether this filter selects all the row of a partition (it's an "identity" filter).
    `boolean` | `shouldInclude(SSTableReader sstable)` Whether the provided sstable may contain data that is selected by this filter (based on the sstable metadata).
    `java.lang.String` | `toCQLString(CFMetaData metadata)`
    `java.lang.String` | `toString(CFMetaData metadata)`

- - ### Field Detail

    - #### serializer

          static final ClusteringIndexFilter.Serializer serializer

  - ### Method Detail

    - #### isReversed

          boolean isReversed()

      Whether the filter query rows in reversed clustering order or not.
      Returns:
        whether the filter query rows in reversed clustering order or not.

    - #### forPaging

          ClusteringIndexFilter forPaging(ClusteringComparator comparator,
                                          Clustering lastReturned,
                                          boolean inclusive)

      Returns a filter for continuing the paging of this filter given the last returned clustering prefix.
      Parameters:
        `comparator` - the comparator for the table this is a filter for.
        `lastReturned` - the last clustering that was returned for the query we are paging for. The resulting filter will be such that results coming after `lastReturned` are returned (where coming after means "greater than" if the filter is not reversed, "lesser than" otherwise; futher, whether the comparison is strict or not depends on `inclusive`).
        `inclusive` - whether or not we want to include the `lastReturned` in the newly returned page of results.
      Returns:
        a new filter that selects results coming after `lastReturned`.

    - #### isFullyCoveredBy

          boolean isFullyCoveredBy(CachedPartition partition)

      Returns whether we can guarantee that a given cached partition contains all the data selected by this filter.
      Parameters:
        `partition` - the cached partition. This method assumed that the rows of this partition contains all the table columns.
      Returns:
        whether we can guarantee that all data selected by this filter are in `partition`.

    - #### isHeadFilter

          boolean isHeadFilter()

      Whether this filter selects the head of a partition (i.e. it isn't reversed and selects all rows up to a certain point).
      Returns:
        whether this filter selects the head of a partition.

    - #### selectsAllPartition

          boolean selectsAllPartition()

      Whether this filter selects all the row of a partition (it's an "identity" filter).
      Returns:
        whether this filter selects all the row of a partition (it's an "identity" filter).

    - #### selects

          boolean selects(Clustering clustering)

      Whether a given row is selected by this filter.
      Parameters:
        `clustering` - the clustering of the row to test the selection of.
      Returns:
        whether the row with clustering `clustering` is selected by this filter.

    - #### filterNotIndexed

          UnfilteredRowIterator filterNotIndexed(ColumnFilter columnFilter,
                                                 UnfilteredRowIterator iterator)

      Returns an iterator that only returns the rows of the provided iterator that this filter selects.

      This method is the "dumb" counterpart to `getSlices(CFMetaData)` in that it has no way to quickly get to what is actually selected, so it simply iterate over it all and filters out what shouldn't be returned. This should be avoided in general. Another difference with `getSlices(CFMetaData)` is that this method also filter the queried columns in the returned result, while the former assumes that the provided iterator has already done it.

      Parameters:
        `columnFilter` - the columns to include in the rows of the result iterator.
        `iterator` - the iterator for which we should filter rows.
      Returns:
        an iterator that only returns the rows (or rather Unfilted) from `iterator` that are selected by this filter.

    - #### getSlices

          Slices getSlices(CFMetaData metadata)

    - #### getUnfilteredRowIterator

          UnfilteredRowIterator getUnfilteredRowIterator(ColumnFilter columnFilter,
                                                         Partition partition)

      Given a partition, returns a row iterator for the rows of this partition that are selected by this filter.
      Parameters:
        `columnFilter` - the columns to include in the rows of the result iterator.
        `partition` - the partition containing the rows to filter.
      Returns:
        a unfiltered row iterator returning those rows (or rather Unfiltered) from `partition` that are selected by this filter.

    - #### shouldInclude

          boolean shouldInclude(SSTableReader sstable)

      Whether the provided sstable may contain data that is selected by this filter (based on the sstable metadata).
      Parameters:
        `sstable` - the sstable for which we want to test the need for inclusion.
      Returns:
        whether `sstable` should be included to answer this filter.

    - #### kind

          ClusteringIndexFilter.Kind kind()

    - #### toString

          java.lang.String toString(CFMetaData metadata)

    - #### toCQLString

          java.lang.String toCQLString(CFMetaData metadata)

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