Package org.apache.solr.uninverting

Interface FieldCache

  • All Known Implementing Classes:
    FieldCacheImpl
    public interface FieldCache
    Expert: Maintains caches of term values.

    Created: May 19, 2004 11:13:14 AM

    Since:
    lucene 1.4
    NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

    • Method Detail

      • getDocsWithField

        org.apache.lucene.util.Bits getDocsWithField​(org.apache.lucene.index.LeafReader reader,
                                             String field,
                                             FieldCache.Parser parser)
                                      throws IOException
        Checks the internal cache for an appropriate entry, and if none is found, reads the terms/points in field and returns a bit set at the size of reader.maxDoc(), with turned on bits for each docid that does have a value for this field.
        Parameters:
        parser - May be null if coming from the inverted index, otherwise can be a FieldCache.PointParser to compute from point values.
        Throws:
        IOException

      • getNumerics

        org.apache.lucene.index.NumericDocValues getNumerics​(org.apache.lucene.index.LeafReader reader,
                                                     String field,
                                                     FieldCache.Parser parser)
                                              throws IOException
        Returns a NumericDocValues over the values found in documents in the given field. If the field was indexed as NumericDocValuesField, it simply uses LeafReader.getNumericDocValues(String) to read the values. Otherwise, it checks the internal cache for an appropriate entry, and if none is found, reads the terms/points in field as longs and returns an array of size reader.maxDoc() of the value each document has in the given field.
        Parameters:
        reader - Used to get field values.
        field - Which field contains the longs.
        parser - Computes long for string values. May be null if the requested field was indexed as NumericDocValuesField or LegacyLongField.
        Returns:
        The values in the given field for each document.
        Throws:
        IOException - If any error occurs.

      • getTerms

        org.apache.lucene.index.BinaryDocValues getTerms​(org.apache.lucene.index.LeafReader reader,
                                                 String field)
                                          throws IOException
        Checks the internal cache for an appropriate entry, and if none is found, reads the term values in field and returns a BinaryDocValues instance, providing a method to retrieve the term (as a BytesRef) per document.
        Parameters:
        reader - Used to get field values.
        field - Which field contains the strings.
        Returns:
        The values in the given field for each document.
        Throws:
        IOException - If any error occurs.

      • getTerms

        org.apache.lucene.index.BinaryDocValues getTerms​(org.apache.lucene.index.LeafReader reader,
                                                 String field,
                                                 float acceptableOverheadRatio)
                                          throws IOException
        Expert: just like getTerms(org.apache.lucene.index.LeafReader,String), but you can specify whether more RAM should be consumed in exchange for faster lookups (default is "true"). Note that the first call for a given reader and field "wins", subsequent calls will share the same cache entry.
        Throws:
        IOException

      • getTermsIndex

        org.apache.lucene.index.SortedDocValues getTermsIndex​(org.apache.lucene.index.LeafReader reader,
                                                      String field)
                                               throws IOException
        Checks the internal cache for an appropriate entry, and if none is found, reads the term values in field and returns a SortedDocValues instance, providing methods to retrieve sort ordinals and terms (as a ByteRef) per document.
        Parameters:
        reader - Used to get field values.
        field - Which field contains the strings.
        Returns:
        The values in the given field for each document.
        Throws:
        IOException - If any error occurs.

      • getTermsIndex

        org.apache.lucene.index.SortedDocValues getTermsIndex​(org.apache.lucene.index.LeafReader reader,
                                                      String field,
                                                      float acceptableOverheadRatio)
                                               throws IOException
        Expert: just like getTermsIndex(org.apache.lucene.index.LeafReader,String), but you can specify whether more RAM should be consumed in exchange for faster lookups (default is "true"). Note that the first call for a given reader and field "wins", subsequent calls will share the same cache entry.
        Throws:
        IOException

      • getDocTermOrds

        org.apache.lucene.index.SortedSetDocValues getDocTermOrds​(org.apache.lucene.index.LeafReader reader,
                                                          String field,
                                                          org.apache.lucene.util.BytesRef prefix)
                                                   throws IOException
        Checks the internal cache for an appropriate entry, and if none is found, reads the term values in field and returns a DocTermOrds instance, providing a method to retrieve the terms (as ords) per document.
        Parameters:
        reader - Used to build a DocTermOrds instance
        field - Which field contains the strings.
        prefix - prefix for a subset of the terms which should be uninverted. Can be null or INT32_TERM_PREFIX or INT64_TERM_PREFIX
        Returns:
        a DocTermOrds instance
        Throws:
        IOException - If any error occurs.

      • getCacheEntries

        FieldCache.CacheEntry[] getCacheEntries()
        EXPERT: Generates an array of CacheEntry objects representing all items currently in the FieldCache.

        NOTE: These CacheEntry objects maintain a strong reference to the Cached Values. Maintaining references to a CacheEntry the AtomicIndexReader associated with it has garbage collected will prevent the Value itself from being garbage collected when the Cache drops the WeakReference.

        WARNING: This API is experimental and might change in incompatible ways in the next release.

      • purgeAllCaches

        void purgeAllCaches()

        EXPERT: Instructs the FieldCache to forcibly expunge all entries from the underlying caches. This is intended only to be used for test methods as a way to ensure a known base state of the Cache (with out needing to rely on GC to free WeakReferences). It should not be relied on for "Cache maintenance" in general application code.

        WARNING: This API is experimental and might change in incompatible ways in the next release.

      • purgeByCacheKey

        void purgeByCacheKey​(org.apache.lucene.index.IndexReader.CacheKey coreCacheKey)
        Expert: drops all cache entries associated with this reader IndexReader.CacheHelper.getKey(). NOTE: this cache key must precisely match the reader that the cache entry is keyed on. If you pass a top-level reader, it usually will have no effect as Lucene now caches at the segment reader level.