Package org.apache.lucene.util.fst

Class FST.Arc<T>

  • Enclosing class:
    FST<T>
    public static final class FST.Arc<T>
extends java.lang.Object
    Represents a single arc.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      (package private) static class  FST.Arc.BitTable
      Helper methods to read the bit-table of a direct addressing node.

    • Constructor Summary

      Constructors 
      Constructor Description
      Arc()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int arcIdx()
      Where we are in the array; only valid if bytesPerArc != 0.
      int bytesPerArc()
      Non-zero if this arc is part of a node with fixed length arcs, which means all arcs for the node are encoded with a fixed number of bytes so that we binary search or direct address.
      FST.Arc<T> copyFrom​(FST.Arc<T> other)
      Returns this
      (package private) int firstLabel()
      First label of a direct addressing node.
      (package private) boolean flag​(int flag)  
      byte flags()  
      boolean isFinal()  
      boolean isLast()  
      int label()  
      (package private) long nextArc()
      Address (into the byte[]) of the next arc - only for list of variable length arc.
      T nextFinalOutput()  
      byte nodeFlags()
      Node header flags.
      int numArcs()
      How many arcs; only valid if bytesPerArc != 0 (fixed length arcs).
      T output()  
      long posArcsStart()
      Where the first arc in the array starts; only valid if bytesPerArc != 0
      long target()
      Ord/address to target node.
      java.lang.String toString()  

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • label

        private int label

      • output

        private T output

      • target

        private long target

      • flags

        private byte flags

      • nextFinalOutput

        private T nextFinalOutput

      • nextArc

        private long nextArc

      • nodeFlags

        private byte nodeFlags

      • bytesPerArc

        private int bytesPerArc

      • posArcsStart

        private long posArcsStart

      • arcIdx

        private int arcIdx

      • numArcs

        private int numArcs

      • bitTableStart

        private long bitTableStart
        Start position in the FST.BytesReader of the presence bits for a direct addressing node, aka the bit-table

      • firstLabel

        private int firstLabel
        First label of a direct addressing node.

      • presenceIndex

        private int presenceIndex
        Index of the current label of a direct addressing node. While arcIdx is the current index in the label range, presenceIndex is its corresponding index in the list of actually present labels. It is equal to the number of bits set before the bit at arcIdx in the bit-table. This field is a cache to avoid to count bits set repeatedly when iterating the next arcs.

    • Constructor Detail

      • Arc

        public Arc()

    • Method Detail

      • flag

        boolean flag​(int flag)

      • isLast

        public boolean isLast()

      • isFinal

        public boolean isFinal()

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • label

        public int label()

      • output

        public T output()

      • target

        public long target()
        Ord/address to target node.

      • flags

        public byte flags()

      • nextFinalOutput

        public T nextFinalOutput()

      • nextArc

        long nextArc()
        Address (into the byte[]) of the next arc - only for list of variable length arc. Or ord/address to the next node if label == FST.END_LABEL.

      • arcIdx

        public int arcIdx()
        Where we are in the array; only valid if bytesPerArc != 0.

      • posArcsStart

        public long posArcsStart()
        Where the first arc in the array starts; only valid if bytesPerArc != 0

      • bytesPerArc

        public int bytesPerArc()
        Non-zero if this arc is part of a node with fixed length arcs, which means all arcs for the node are encoded with a fixed number of bytes so that we binary search or direct address. We do when there are enough arcs leaving one node. It wastes some bytes but gives faster lookups.

      • numArcs

        public int numArcs()
        How many arcs; only valid if bytesPerArc != 0 (fixed length arcs). For a node designed for binary search this is the array size. For a node designed for direct addressing, this is the label range.