com.sun.labs.minion.indexer.dictionary
Class DictionaryHeader

java.lang.Object
  com.sun.labs.minion.indexer.dictionary.DictionaryHeader

public class DictionaryHeader
extends java.lang.Object

A class that contains the header information for a dictionary.

Field Summary

protected static int	BAD_MAGIC
protected int	entryInfoOffsetsBytes The number of bytes used to encode the offsets for the term information.
protected long	entryInfoOffsetsPos The position of the entry info offsets buffer.
protected int	entryInfoOffsetsSize The size of the entry info offsets buffer.
protected long	entryInfoPos The position of the entry info buffer.
protected int	entryInfoSize The size of the entry info buffer.
protected static int	GOOD_MAGIC Good magic.
protected int	idToPosnBytes The number of bytes that each ID to posn map entry requires.
protected long	idToPosnPos The offset of the ID to position map in the file.
protected int	idToPosnSize The size of the map from ID to position in the dictionary.
protected int	magic A magic number, written last.
protected int	maxEntryID The maximum ID assigned to an entry, which may be different than the size.
protected int	nameOffsetsBytes The number of bytes used to encode the offsets for the uncompressed names.
protected long	nameOffsetsPos The position of the names offset buffer.
protected int	nameOffsetsSize The size of the names offset buffer.
protected long	namesPos The position of the names buffer.
protected int	namesSize The size of the names buffer.
protected int	nOffsets The number of name offsets.
protected long[]	postEnd The ending offsets for postings associated with this dictionary.
protected long[]	postStart The starting offsets for postings associated with this dictionary.
protected int	size The number of entries in the dictionary.

Constructor Summary

DictionaryHeader(int n)
Creates an empty header, suitable for filling during dumping.

DictionaryHeader(java.io.RandomAccessFile dictFile)
Creates a dictionary header by reading it from the provided channel.

Method Summary

protected void	computeValues() Computes derived values.
int	getMaxID() Gets the maximum ID in the dictionary.
void	goodMagic() Tells the header that the magic is good.
void	read(java.io.RandomAccessFile dictFile) Reads a dictionary header from the given channel.
java.lang.String	toString()
void	write(java.io.RandomAccessFile dictFile) Writes a dictionary header to the given channel.

Methods inherited from class java.lang.Object

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

Field Detail

magic

protected int magic

A magic number, written last.

size

protected int size

The number of entries in the dictionary.

maxEntryID

protected int maxEntryID

The maximum ID assigned to an entry, which may be different than the size.

idToPosnPos

protected long idToPosnPos

The offset of the ID to position map in the file.

idToPosnSize

protected int idToPosnSize

The size of the map from ID to position in the dictionary.

idToPosnBytes

protected int idToPosnBytes

The number of bytes that each ID to posn map entry requires.

nameOffsetsPos

protected long nameOffsetsPos

The position of the names offset buffer.

nameOffsetsSize

protected int nameOffsetsSize

The size of the names offset buffer.

nameOffsetsBytes

protected int nameOffsetsBytes

The number of bytes used to encode the offsets for the uncompressed names.

namesPos

protected long namesPos

The position of the names buffer.

namesSize

protected int namesSize

The size of the names buffer.

nOffsets

protected int nOffsets

The number of name offsets.

entryInfoOffsetsPos

protected long entryInfoOffsetsPos

The position of the entry info offsets buffer.

entryInfoOffsetsSize

protected int entryInfoOffsetsSize

The size of the entry info offsets buffer.

entryInfoOffsetsBytes

protected int entryInfoOffsetsBytes

The number of bytes used to encode the offsets for the term information.

entryInfoPos

protected long entryInfoPos

The position of the entry info buffer.

entryInfoSize

protected int entryInfoSize

The size of the entry info buffer.

postStart

protected long[] postStart

The starting offsets for postings associated with this dictionary.

postEnd

protected long[] postEnd

The ending offsets for postings associated with this dictionary.

GOOD_MAGIC

protected static final int GOOD_MAGIC

Good magic.

See Also:

Constant Field Values

BAD_MAGIC

protected static final int BAD_MAGIC

See Also:

Constant Field Values

Constructor Detail

DictionaryHeader

public DictionaryHeader(int n)

Creates an empty header, suitable for filling during dumping.

Parameters:

n - The number of postings channels associated with the dictionary for which this is a header.

DictionaryHeader

public DictionaryHeader(java.io.RandomAccessFile dictFile)
                 throws java.io.IOException

Creates a dictionary header by reading it from the provided channel.

Throws:

java.io.IOException

Method Detail

computeValues

protected void computeValues()

Computes derived values.

goodMagic

public void goodMagic()

Tells the header that the magic is good.

read

public void read(java.io.RandomAccessFile dictFile)
          throws java.io.IOException

Reads a dictionary header from the given channel.

Throws:

java.io.IOException

write

public void write(java.io.RandomAccessFile dictFile)
           throws java.io.IOException

Writes a dictionary header to the given channel.

Throws:

java.io.IOException

getMaxID

public int getMaxID()

Gets the maximum ID in the dictionary.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object