ivory.core.data.stat

Class DocLengthTable2B

java.lang.Object

ivory.core.data.stat.DocLengthTable2B

All Implemented Interfaces:

DocLengthTable

public class DocLengthTable2B
extends Object
implements DocLengthTable

Object that keeps track of the length of each document in the collection as a two-byte integer (shorts). Document lengths are measured in number of terms.

Document length data is stored in a serialized data file, in the following format:

• An integer that specifies the docno offset d, where d + 1 is the first docno in the collection.
• An integer that specifies the number of documents in the collection n.
• Exactly n shorts, one for each document in the collection.

Since the documents are numbered sequentially starting at d + 1, each short corresponds unambiguously to a particular document.

Author:

Jimmy Lin

Constructor Summary

Constructors

Constructor and Description
DocLengthTable2B(Path file) Creates a new DocLengthTable2B.
DocLengthTable2B(Path file, FileSystem fs) Creates a new DocLengthTable2B.

Method Summary

Methods

Modifier and Type	Method and Description
float	getAvgDocLength() Returns the average document length.
int	getDocCount() Returns number of documents in the collection.
int	getDocLength(int docno) Returns the length of a document.
int	getDocnoOffset() Returns the first docno in this collection.
static void	main(String[] args)

Methods inherited from class java.lang.Object

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

Constructor Detail

DocLengthTable2B

public DocLengthTable2B(Path file)
                 throws IOException

Creates a new DocLengthTable2B.

Parameters:

file - document length data file

Throws:

IOException

DocLengthTable2B

public DocLengthTable2B(Path file,
                FileSystem fs)
                 throws IOException

Creates a new DocLengthTable2B.

Parameters:

file - document length data file

fs - FileSystem to read from

Throws:

IOException

Method Detail

getAvgDocLength

public float getAvgDocLength()

Description copied from interface: DocLengthTable

Returns the average document length.

Specified by:

getAvgDocLength in interface DocLengthTable

getDocCount

public int getDocCount()

Description copied from interface: DocLengthTable

Returns number of documents in the collection.

Specified by:

getDocCount in interface DocLengthTable

getDocLength

public int getDocLength(int docno)

Description copied from interface: DocLengthTable

Returns the length of a document.

Specified by:

getDocLength in interface DocLengthTable

getDocnoOffset

public int getDocnoOffset()

Description copied from interface: DocLengthTable

Returns the first docno in this collection. All documents are number consecutively from this value.

Specified by:

getDocnoOffset in interface DocLengthTable

main

public static void main(String[] args)
                 throws Exception

Throws:

Exception