org.terrier.structures.postings
Class BasicPostingImpl

java.lang.Object
  org.terrier.structures.postings.BasicPostingImpl

All Implemented Interfaces:

org.apache.hadoop.io.Writable, Posting, WritablePosting

Direct Known Subclasses:

BasicIterablePosting, BlockPostingImpl, FieldPostingImpl

public class BasicPostingImpl
extends java.lang.Object
implements WritablePosting

Implementation of a Posting that is non-iterable.

Since:

3.0

Author:

Craig Macdonald

Field Summary

protected int	id id of the posting
protected int	tf frequency of this posting

Constructor Summary

BasicPostingImpl()
Empty constructor - needed for Writable

BasicPostingImpl(int docid, int frequency)
Constructor that sets both id and frequency

Method Summary

WritablePosting	asWritablePosting() Copies this posting to one free of an iterator.
int	getDocumentLength() Returns 0
int	getFrequency() Return the frequency of the term in the current document
int	getId() Return the id of the current posting.
void	readFields(java.io.DataInput in) Reads the a single posting (not an iterable posting - use BitPostingIndex for that)
void	setId(int _id) Set the id of this posting
java.lang.String	toString() Makes a human readable form of this posting
void	write(java.io.DataOutput out) Writes the current posting (not an iterable posting - use DirectInvertedOutputStream for that).

Methods inherited from class java.lang.Object

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

Field Detail

id

protected int id

id of the posting

tf

protected int tf

frequency of this posting

Constructor Detail

BasicPostingImpl

public BasicPostingImpl()

Empty constructor - needed for Writable

BasicPostingImpl

public BasicPostingImpl(int docid,
                        int frequency)

Constructor that sets both id and frequency

Method Detail

getId

public int getId()

Return the id of the current posting. For the inverted index, this is the docid; for the direct index it corresponds to the term id

Specified by:

getId in interface Posting

Returns:

id of the posting

getFrequency

public int getFrequency()

Return the frequency of the term in the current document

Specified by:

getFrequency in interface Posting

Returns:

frequency of posting, in tokens

readFields

public void readFields(java.io.DataInput in)
                throws java.io.IOException

Reads the a single posting (not an iterable posting - use BitPostingIndex for that)

Specified by:

readFields in interface org.apache.hadoop.io.Writable

Throws:

java.io.IOException

write

public void write(java.io.DataOutput out)
           throws java.io.IOException

Writes the current posting (not an iterable posting - use DirectInvertedOutputStream for that). Compression using this method is not expected to be comparable to bit-level compression.

Specified by:

write in interface org.apache.hadoop.io.Writable

Throws:

java.io.IOException

setId

public void setId(int _id)

Set the id of this posting

Specified by:

setId in interface Posting

getDocumentLength

public int getDocumentLength()

Returns 0

Specified by:

getDocumentLength in interface Posting

Returns:

length of the document of the current posting in tokens.

asWritablePosting

public WritablePosting asWritablePosting()

Copies this posting to one free of an iterator. Kind of like a clone.

Specified by:

asWritablePosting in interface Posting

Returns:

an identical posting, but which can be maniulated free of this iterator

toString

public java.lang.String toString()

Makes a human readable form of this posting

Overrides:

toString in class java.lang.Object