org.terrier.structures.indexing.singlepass

Class RunIterator

java.lang.Object

org.terrier.structures.indexing.singlepass.RunIterator

All Implemented Interfaces:

Closeable, AutoCloseable, Iterator<PostingInRun>

Direct Known Subclasses:

FileRunIterator, HadoopRunPostingIterator

public abstract class RunIterator
extends Object
implements Iterator<PostingInRun>, Closeable

An abstract base class which allows PostingInRuns to be iterated over. Implementations are typically more generic versions of RunReader from Terrier 2.0 and 2.1.

Since:

2.2

Author:

Craig Macdonald

Field Summary

Fields

Modifier and Type	Field and Description
protected int	flushNo Run/Flush that the current posting came from
protected int	numberOfFields
protected PostingInRun	posting current posting
protected Class<? extends PostingInRun>	postingClass class that new postings are derived from

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	RunIterator(Class<? extends PostingInRun> _postingClass, int _runNo, int _numberOfFields) create a new instance of this class.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() close this RunIterator
protected void	createPosting() Create a new posting
PostingInRun	current() returns the current posting
int	getRunNo() Get the run/flush number that the current posting came from
abstract boolean	hasNext() iterator implementation
abstract PostingInRun	next() iterator implementation
void	remove() unsupported iterator method

Methods inherited from class java.lang.Object

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

Field Detail

postingClass

protected Class<? extends PostingInRun> postingClass

class that new postings are derived from

posting

protected PostingInRun posting

current posting

flushNo

protected int flushNo

Run/Flush that the current posting came from

numberOfFields

protected int numberOfFields

Constructor Detail

RunIterator

protected RunIterator(Class<? extends PostingInRun> _postingClass,
           int _runNo,
           int _numberOfFields)

create a new instance of this class.

Parameters:

_postingClass - Class of the PostingInRun type that postings in this run have

_runNo - The run number currently being processed

Method Detail

createPosting

protected void createPosting()
                      throws Exception

Create a new posting

Throws:

Exception

getRunNo

public int getRunNo()

Get the run/flush number that the current posting came from

hasNext

public abstract boolean hasNext()

iterator implementation

Specified by:

hasNext in interface Iterator<PostingInRun>

next

public abstract PostingInRun next()

iterator implementation

Specified by:

next in interface Iterator<PostingInRun>

current

public PostingInRun current()

returns the current posting

remove

public void remove()

unsupported iterator method

Specified by:

remove in interface Iterator<PostingInRun>

close

public void close()
           throws IOException

close this RunIterator

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException