Package org.apache.lucene.codecs.uniformsplit

Class IntersectBlockReader.AutomatonNextTermCalculator

java.lang.Object
org.apache.lucene.codecs.uniformsplit.IntersectBlockReader.AutomatonNextTermCalculator
Enclosing class:
IntersectBlockReader
protected class IntersectBlockReader.AutomatonNextTermCalculator extends Object
This is mostly a copy of AutomatonTermsEnum. Since it's an inner class, the outer class can call methods that ATE does not expose. It'd be nice if ATE's logic could be more extensible.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected short
    curGen
     
    protected boolean
    linear
     
    protected final BytesRef
    linearUpperBound
     
    protected final IntsRefBuilder
    savedStates
     
    protected final BytesRefBuilder
    seekBytesRef
     
    protected final Transition
    transition
     
    protected final short[]
    visited
     

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    AutomatonNextTermCalculator(CompiledAutomaton compiled)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    protected int
    backtrack(int position)
    Attempts to backtrack thru the string after encountering a dead end at some given position.
    protected boolean
    isLinearState(BytesRef term)
    True if the current state of the automata is best iterated linearly (without seeking).
    protected boolean
    isVisited(int state)
    Indicates whether the given state has been visited.
    protected BytesRef
    nextSeekTerm(BytesRef term)
     
    protected boolean
    nextString()
    Increments the byte buffer to the next String in binary order after s that will not put the machine into a reject state.
    protected boolean
    nextString(int state, int position)
    Returns the next String in lexicographic order that will not put the machine into a reject state.
    protected void
    setLinear(int position)
    Sets the enum to operate in linear fashion, as we have found a looping transition at position: we set an upper bound and act like a TermRangeQuery for this portion of the term space.
    protected void
    setVisited(int state)
    Records the given state has been visited.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • visited

      protected final short[] visited

    • curGen

      protected short curGen

    • seekBytesRef

      protected final BytesRefBuilder seekBytesRef

    • linear

      protected boolean linear

    • linearUpperBound

      protected final BytesRef linearUpperBound

    • transition

      protected final Transition transition

    • savedStates

      protected final IntsRefBuilder savedStates

  • Constructor Details

    • AutomatonNextTermCalculator

      protected AutomatonNextTermCalculator(CompiledAutomaton compiled)

  • Method Details

    • setVisited

      protected void setVisited(int state)
      Records the given state has been visited.

    • isVisited

      protected boolean isVisited(int state)
      Indicates whether the given state has been visited.

    • isLinearState

      protected boolean isLinearState(BytesRef term)
      True if the current state of the automata is best iterated linearly (without seeking).

    • nextSeekTerm

      protected BytesRef nextSeekTerm(BytesRef term)
      See Also:

    • setLinear

      protected void setLinear(int position)
      Sets the enum to operate in linear fashion, as we have found a looping transition at position: we set an upper bound and act like a TermRangeQuery for this portion of the term space.

    • nextString

      protected boolean nextString()
      Increments the byte buffer to the next String in binary order after s that will not put the machine into a reject state. If such a string does not exist, returns false.

      The correctness of this method depends upon the automaton being deterministic, and having no transitions to dead states.

      Returns:
      true if more possible solutions exist for the DFA

    • nextString

      protected boolean nextString(int state, int position)
      Returns the next String in lexicographic order that will not put the machine into a reject state.

      This method traverses the DFA from the given position in the String, starting at the given state.

      If this cannot satisfy the machine, returns false. This method will walk the minimal path, in lexicographic order, as long as possible.

      If this method returns false, then there might still be more solutions, it is necessary to backtrack to find out.

      Parameters:
      state - current non-reject state
      position - useful portion of the string
      Returns:
      true if more possible solutions exist for the DFA from this position

    • backtrack

      protected int backtrack(int position)
      Attempts to backtrack thru the string after encountering a dead end at some given position. Returns false if no more possible strings can match.
      Parameters:
      position - current position in the input String
      Returns:
      position >= 0 if more possible solutions exist for the DFA