## org.apache.lucene.search
Class CachingSpanFilter

    java.lang.Object
      org.apache.lucene.search.Filter
          org.apache.lucene.search.SpanFilter
              org.apache.lucene.search.CachingSpanFilter

All Implemented Interfaces:
  Serializable

    public class CachingSpanFilter

extends SpanFilter

Wraps another SpanFilter's result and caches it. The purpose is to allow filters to simply filter, and then wrap with this class to add caching.

See Also:
  Serialized Form

Constructor Summary
`CachingSpanFilter(SpanFilter filter)` New deletions always result in a cache miss, by default (`CachingWrapperFilter.DeletesMode.RECACHE`.
`CachingSpanFilter(SpanFilter filter, CachingWrapperFilter.DeletesMode deletesMode)`

Method Summary
`SpanFilterResult` `bitSpans(IndexReader reader)` Returns a SpanFilterResult with true for documents which should be permitted in search results, and false for those that should not and Spans for where the true docs match.
`boolean` `equals(Object o)`
`DocIdSet` `getDocIdSet(IndexReader reader)` Creates a `DocIdSet` enumerating the documents that should be permitted in search results.
`int` `hashCode()`
`String` `toString()`

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

Constructor Detail

### CachingSpanFilter

    public CachingSpanFilter(SpanFilter filter)

  New deletions always result in a cache miss, by default (`CachingWrapperFilter.DeletesMode.RECACHE`.

  Parameters:
    `filter` - Filter to cache results of

### CachingSpanFilter

    public CachingSpanFilter(SpanFilter filter,
                             CachingWrapperFilter.DeletesMode deletesMode)

Parameters:
  `filter` - Filter to cache results of
  `deletesMode` - See `CachingWrapperFilter.DeletesMode`

Method Detail

### getDocIdSet

    public DocIdSet getDocIdSet(IndexReader reader)
                         throws IOException

  Description copied from class: `Filter`
  Creates a `DocIdSet` enumerating the documents that should be permitted in search results. NOTE: null can be returned if no documents are accepted by this Filter.

  Note: This method will be called once per segment in the index during searching. The returned `DocIdSet` must refer to document IDs for that segment, not for the top-level reader.

  Specified by:
    `getDocIdSet` in class `Filter`
  Parameters:
    `reader` - a `IndexReader` instance opened on the index currently searched on. Note, it is likely that the provided reader does not represent the whole underlying index i.e. if the index has more than one segment the given reader only represents a single segment.
  Returns:
    a DocIdSet that provides the documents which should be permitted or prohibited in search results. NOTE: null can be returned if no documents will be accepted by this Filter.
  Throws:
    `IOException`
  See Also:
    `DocIdBitSet`

### bitSpans

    public SpanFilterResult bitSpans(IndexReader reader)
                              throws IOException

  Description copied from class: `SpanFilter`
  Returns a SpanFilterResult with true for documents which should be permitted in search results, and false for those that should not and Spans for where the true docs match.

  Specified by:
    `bitSpans` in class `SpanFilter`
  Parameters:
    `reader` - The `IndexReader` to load position and DocIdSet information from
  Returns:
    A `SpanFilterResult`
  Throws:
    `IOException` - if there was an issue accessing the necessary information

### toString

    public String toString()

  Overrides:
    `toString` in class `Object`

### equals

    public boolean equals(Object o)

  Overrides:
    `equals` in class `Object`

### hashCode

    public int hashCode()

  Overrides:
    `hashCode` in class `Object`