Package org.terrier.structures

Class LexiconEntry

java.lang.Object

org.terrier.structures.LexiconEntry

All Implemented Interfaces:

java.io.Serializable, org.apache.hadoop.io.Writable, EntryStatistics, Pointer

Direct Known Subclasses:

BasicLexiconEntry, BasicTermStatsLexiconEntry, MemoryLexiconEntry, MultiLexiconEntry, Tr4BasicLexiconEntry, Tr4BasicTermStatsLexiconEntry

public abstract class LexiconEntry
extends java.lang.Object
implements EntryStatistics, Pointer, org.apache.hadoop.io.Writable

Base class for all LexiconEntry implementations. A LexiconEntry represents the statistics of a term in the Lexicon, and a pointer to the term's location in a PostingIndex. For these reasons, this class implements Pointer and EntryStatistics.

Author:

Craig Macdonald

See Also:

Lexicon, Pointer, EntryStatistics, Serialized Form

Constructor Summary

Constructors

Constructor	Description
LexiconEntry()

Method Summary

Modifier and Type	Method	Description
boolean	equals(java.lang.Object obj)	Does this refer to the same term
int	getNumberOfEntries()	Pointer implementation: how many entries in the inverted index.
EntryStatistics	getWritableEntryStatistics()	Get a writable copy of the EntryStatistics.
int	hashCode()	hash this object based on termid
java.lang.String	pointerToString()	Returns a textual representation of the pointer alone
void	setNumberOfEntries(int n)	Update the number of entries in the pointer
void	setPointer(Pointer p)	Update the pointer
abstract void	setStatistics(int n_t, int TF)	Update the document frequency and term frequency
abstract void	setTermId(int newTermId)	Set the term ID, the integer representation of the term in the index, e.g.
java.lang.String	toString()	returns a string representation of this lexicon entry

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.terrier.structures.EntryStatistics

add, getDocumentFrequency, getFrequency, getMaxFrequencyInDocuments, getTermId, setDocumentFrequency, setFrequency, setMaxFrequencyInDocuments, subtract

Methods inherited from interface org.apache.hadoop.io.Writable

readFields, write

Constructor Detail

LexiconEntry

public LexiconEntry()

Method Detail

toString

public java.lang.String toString()

returns a string representation of this lexicon entry

Overrides:

toString in class java.lang.Object

setTermId

public abstract void setTermId(int newTermId)

Set the term ID, the integer representation of the term in the index, e.g. as used in direct index posting structures.

setStatistics

public abstract void setStatistics(int n_t,
                                   int TF)

Update the document frequency and term frequency

getNumberOfEntries

public int getNumberOfEntries()

Pointer implementation: how many entries in the inverted index. Usually the same as getDocumentFrequency().

Specified by:

getNumberOfEntries in interface Pointer

Returns:

the number of "things" that this pointer refers to.

setNumberOfEntries

public void setNumberOfEntries(int n)

Update the number of entries in the pointer

Specified by:

setNumberOfEntries in interface Pointer

Parameters:

n - the number of "things" that the pointer refers to.

pointerToString

public java.lang.String pointerToString()

Description copied from interface: Pointer

Returns a textual representation of the pointer alone

Specified by:

pointerToString in interface Pointer

setPointer

public void setPointer(Pointer p)

Update the pointer

Specified by:

setPointer in interface Pointer

Parameters:

p - other pointer to update the pointer in this object.

getWritableEntryStatistics

public EntryStatistics getWritableEntryStatistics()

Get a writable copy of the EntryStatistics. Just returns itself.

Specified by:

getWritableEntryStatistics in interface EntryStatistics

Returns:

an identical entry statistics, but which can be reused.

equals

public boolean equals(java.lang.Object obj)

Does this refer to the same term

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

hash this object based on termid

Overrides:

hashCode in class java.lang.Object