Package org.apache.lucene.codecs

Class MultiLevelSkipListReader

java.lang.Object
org.apache.lucene.codecs.MultiLevelSkipListReader
All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
Lucene40SkipListReader
public abstract class MultiLevelSkipListReader extends Object implements Closeable
This abstract class reads skip lists with multiple levels. See MultiLevelSkipListWriter for the information about the encoding of the multi level skip lists. Subclasses must implement the abstract method readSkipData(int, IndexInput) which defines the actual format of the skip data.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected int
    maxNumberOfSkipLevels
    the maximum number of skip levels possible for this index
    protected int[]
    skipDoc
    Doc id of current skip entry per level.

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    MultiLevelSkipListReader(IndexInput skipStream, int maxSkipLevels, int skipInterval)
    Creates a MultiLevelSkipListReader, where skipInterval and skipMultiplier are the same.
    protected
    MultiLevelSkipListReader(IndexInput skipStream, int maxSkipLevels, int skipInterval, int skipMultiplier)
    Creates a MultiLevelSkipListReader.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
     
    int
    getDoc()
    Returns the id of the doc to which the last call of skipTo(int) has skipped.
    void
    init(long skipPointer, int df)
    Initializes the reader, for reuse on a new term.
    protected abstract int
    readSkipData(int level, IndexInput skipStream)
    Subclasses must implement the actual skip data encoding in this method.
    protected void
    seekChild(int level)
    Seeks the skip entry on the given level
    protected void
    setLastSkipData(int level)
    Copies the values of the last read skip entry on this level
    int
    skipTo(int target)
    Skips entries to the first beyond the current whose document number is greater than or equal to target.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • maxNumberOfSkipLevels

      protected int maxNumberOfSkipLevels
      the maximum number of skip levels possible for this index

    • skipDoc

      protected int[] skipDoc
      Doc id of current skip entry per level.

  • Constructor Details

    • MultiLevelSkipListReader

      protected MultiLevelSkipListReader(IndexInput skipStream, int maxSkipLevels, int skipInterval, int skipMultiplier)
      Creates a MultiLevelSkipListReader.

    • MultiLevelSkipListReader

      protected MultiLevelSkipListReader(IndexInput skipStream, int maxSkipLevels, int skipInterval)
      Creates a MultiLevelSkipListReader, where skipInterval and skipMultiplier are the same.

  • Method Details

    • getDoc

      public int getDoc()
      Returns the id of the doc to which the last call of skipTo(int) has skipped.

    • skipTo

      public int skipTo(int target) throws IOException
      Skips entries to the first beyond the current whose document number is greater than or equal to target. Returns the current doc count.
      Throws:
      IOException

    • seekChild

      protected void seekChild(int level) throws IOException
      Seeks the skip entry on the given level
      Throws:
      IOException

    • close

      public void close() throws IOException
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Throws:
      IOException

    • init

      public void init(long skipPointer, int df)
      Initializes the reader, for reuse on a new term.

    • readSkipData

      protected abstract int readSkipData(int level, IndexInput skipStream) throws IOException
      Subclasses must implement the actual skip data encoding in this method.
      Parameters:
      level - the level skip data shall be read from
      skipStream - the skip stream to read from
      Throws:
      IOException

    • setLastSkipData

      protected void setLastSkipData(int level)
      Copies the values of the last read skip entry on this level