org.egothor.merger
Class ConcatLists

java.lang.Object
  org.egothor.merger.ConcatLists

All Implemented Interfaces:

IListItem, IListReader

Direct Known Subclasses:

ConcatListReader

public abstract class ConcatLists
extends java.lang.Object
implements IListReader

A ConcatIListReader is some collection (array) of IListReaders. Essentially, this is an array of inverted lists. This class can be implemented as sub-class of ConcatEnums, but we have not got the IListReaders to Enumerations, so it must wait.

Author:

Leo Galambos

Constructor Summary

ConcatLists()
Constructor for the ConcatListReader object

Method Summary

void	close() Does nothing by default.
long	getPostings() Return the number of postings.
java.lang.String	getTerm() Return the term for this ConcatListReader.
boolean	next() Move to the next item in the inverted list.
Proximities	openProx() Return an access object to the proximity list.
void	setTerm(java.lang.String term) Sets the term attribute of the ConcatLists object
boolean	skipTo(long uid) Skip to the given position in the inverted list.
abstract void	switchContext() This method would close the current list reader, and set new values for current and current_offset attributes.
long	uid() Identification of the document.
int	weight() Calculated vector value.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConcatLists

public ConcatLists()

Constructor for the ConcatListReader object

Method Detail

setTerm

public void setTerm(java.lang.String term)

Sets the term attribute of the ConcatLists object

Parameters:

term - The new term value

getPostings

public long getPostings()

Return the number of postings.

Specified by:

getPostings in interface IListReader

Returns:

the number of postings

getTerm

public java.lang.String getTerm()

Return the term for this ConcatListReader. The term is initiated in the constructor.

Specified by:

getTerm in interface IListReader

Returns:

the term

switchContext

public abstract void switchContext()

This method would close the current list reader, and set new values for current and current_offset attributes. If there is not any next list, then current must be set to null .

next

public boolean next()

Description copied from interface: IListReader

Move to the next item in the inverted list.

Specified by:

next in interface IListReader

Returns:

true if the next item exists

skipTo

public boolean skipTo(long uid)

Skip to the given position in the inverted list.

Specified by:

skipTo in interface IListReader

Parameters:

uid - the position to skip to

Returns:

Description of the Return Value

close

public void close()

Does nothing by default.

Specified by:

close in interface IListReader

openProx

public Proximities openProx()

Description copied from interface: IListItem

Return an access object to the proximity list.

Specified by:

openProx in interface IListItem

Returns:

a Proximities object

uid

public long uid()

Description copied from interface: IListItem

Identification of the document. If this value is lower than 0, then this item ought to be supposed to be invalid.

Specified by:

uid in interface IListItem

weight

public int weight()

Description copied from interface: IListItem

Calculated vector value.

Specified by:

weight in interface IListItem