org.terrier.structures.postings

Class PostingUtil

java.lang.Object

org.terrier.structures.postings.PostingUtil

public class PostingUtil
extends Object

Handy methods for Posting classes, such as obtaining all ids in a posting list, or selecting the minimum id in an array of posting lists.

Since:

3.0

Author:

Craig Macdonald

Constructor Summary

Constructors

Constructor and Description
PostingUtil()

Method Summary

Modifier and Type	Method and Description
static int[][]	getAllPostings(IterablePosting ip) Get an array of all the ids in a given IterablePosting stream, where the length of the stream is known
static int[][]	getAllPostings(IterablePosting ip, int numPointers) Get an array of all the ids and frequencies in a given IterablePosting stream, where the length of the stream is unknown
static int[][]	getAllPostingsWithFields(IterablePosting ip, int numPointers, int fieldCount) Get an array of all the ids in a given IterablePosting stream, where the length of the stream is known
static int[]	getIds(IterablePosting ip) Get an array of all the ids in a given IterablePosting stream
static int[]	getIds(IterablePosting ip, int numPointers) Get an array of all the ids in a given IterablePosting stream, where the length of the stream is known
static int	selectMinimumDocId(IterablePosting[] postingListArray) Returns the minimum docid of the current postings in the array of IterablePostings

Methods inherited from class java.lang.Object

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

Constructor Detail

PostingUtil

public PostingUtil()

Method Detail

getIds

public static int[] getIds(IterablePosting ip)
                    throws IOException

Get an array of all the ids in a given IterablePosting stream

Throws:

IOException

getIds

public static int[] getIds(IterablePosting ip,
                           int numPointers)
                    throws IOException

Get an array of all the ids in a given IterablePosting stream, where the length of the stream is known

Throws:

IOException

getAllPostings

public static int[][] getAllPostings(IterablePosting ip,
                                     int numPointers)
                              throws IOException

Get an array of all the ids and frequencies in a given IterablePosting stream, where the length of the stream is unknown

Throws:

IOException

getAllPostingsWithFields

public static int[][] getAllPostingsWithFields(IterablePosting ip,
                                               int numPointers,
                                               int fieldCount)
                                        throws IOException

Get an array of all the ids in a given IterablePosting stream, where the length of the stream is known

Throws:

IOException

getAllPostings

public static int[][] getAllPostings(IterablePosting ip)
                              throws IOException

Get an array of all the ids in a given IterablePosting stream, where the length of the stream is known

Throws:

IOException

selectMinimumDocId

public static int selectMinimumDocId(IterablePosting[] postingListArray)

Returns the minimum docid of the current postings in the array of IterablePostings

Returns:

minimum docid, or -1 if all postings have ended.