Package org.apache.lucene.codecs.uniformsplit

Class IntersectBlockReader

    • Field Detail

      • NUM_CONSECUTIVELY_REJECTED_TERMS_THRESHOLD

        protected final int NUM_CONSECUTIVELY_REJECTED_TERMS_THRESHOLD
        Threshold that controls when to attempt to jump to a block away.

        This counter is 0 when entering a block. It is incremented each time a term is rejected by the automaton. When the counter is greater than or equal to this threshold, then we compute the next term accepted by the automaton, with IntersectBlockReader.AutomatonNextTermCalculator, and we jump to a block away if the next term accepted is greater than the immediate next term in the block.

        A low value, for example 1, improves the performance of automatons requiring many jumps, for example FuzzyQuery and most WildcardQuery. A higher value improves the performance of automatons with less or no jump, for example PrefixQuery. A threshold of 4 seems to be a good balance.

        See Also:
        Constant Field Values

      • automaton

        protected final Automaton automaton

      • finite

        protected final boolean finite

      • commonSuffix

        protected final BytesRef commonSuffix

      • minTermLength

        protected final int minTermLength

      • seekTerm

        protected BytesRef seekTerm
        Set this when our current mode is seeking to this term. Set to null after.

      • numMatchedBytes

        protected int numMatchedBytes
        Number of bytes accepted by the automaton when validating the current term.

      • states

        protected int[] states
        Automaton states reached when validating the current term, from 0 to numMatchedBytes - 1.

      • numConsecutivelyRejectedTerms

        protected int numConsecutivelyRejectedTerms
        Counter of the number of consecutively rejected terms. Depending on NUM_CONSECUTIVELY_REJECTED_TERMS_THRESHOLD, this may trigger a jump to a block away.

    • Method Detail

      • getMinTermLength

        protected int getMinTermLength()
        Computes the minimal length of the terms accepted by the automaton. This speeds up the term scanning for automatons accepting a finite language.

      • nextTermInBlockMatching

        protected BytesRef nextTermInBlockMatching()
                                    throws IOException
        Finds the next block line that matches (accepted by the automaton), or null when at end of block.
        Returns:
        The next term in the current block that is accepted by the automaton; or null if none.
        Throws:
        IOException

      • endsWithCommonSuffix

        protected boolean endsWithCommonSuffix​(byte[] termBytes,
                                       int termLength)
        Indicates whether the given term ends with the automaton common suffix. This allows to quickly skip terms that the automaton would reject eventually.

      • nextBlock

        protected boolean nextBlock()
                     throws IOException
        Opens the next block. Depending on the blockIteration order, it may be the very next block, or a block away that may contain seekTerm.
        Returns:
        true if the next block is opened; false if there is no blocks anymore and the iteration is over.
        Throws:
        IOException