org.apache.lucene.mark

Class BasicWordIter

Object

BasicWordIter

All Implemented Interfaces:

Cloneable, WordIter

Direct Known Subclasses:

BoundedWordIter, ChunkedWordIter

public class BasicWordIter
extends Object
implements WordIter, Cloneable

Utility class used to iterate either forward or backward through the tokens in a single string of text.

Created: Dec 13, 2004

Author:

Martin Haye

Field Summary

Fields

Modifier and Type	Field and Description
protected int	maxWordPos Word position of the last token
protected String	text The original text to which the tokens refer
protected Token[]	tokens Array of tokens, holding words from the current chunk
protected int	tokNum Current token this iterator is pointed at
protected int	wordPos Word position of the curren token

Fields inherited from interface WordIter

FIELD_END, FIELD_START, TERM_END, TERM_END_PLUS, TERM_START

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BasicWordIter() Do-nothing constructor - should only be used by derived classes that perform their own initialization.
	BasicWordIter(String text, TokenStream stream) Construct the iterator and read in tokens from the given stream.

Method Summary

Modifier and Type	Method and Description
Object	clone() Make an exact, independent, copy of this iterator
MarkPos	getPos(int startOrEnd) Retrieve the start or end of the current position.
void	getPos(MarkPos pos, int startOrEnd) Replace the position within a MarkPos created by WordIter.getPos(int) using the iterator's current position.
boolean	next(boolean force) Advance to the next word.
boolean	prev(boolean force) Back up to the previous word.
void	seekFirst(int targetPos, boolean force) Reposition the iterator at the first word whose position is greater than or equal to 'wordPos'.
void	seekLast(int targetPos, boolean force) Reposition the iterator at the last word whose position is less than or equal to 'wordPos'.
String	term() Retrieve the text of the term at the current position

Methods inherited from class Object

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

Field Detail

text

protected String text

The original text to which the tokens refer

tokens

protected Token[] tokens

Array of tokens, holding words from the current chunk

tokNum

protected int tokNum

Current token this iterator is pointed at

wordPos

protected int wordPos

Word position of the curren token

maxWordPos

protected int maxWordPos

Word position of the last token

Constructor Detail

BasicWordIter

public BasicWordIter(String text,
                     TokenStream stream)
              throws IOException

Construct the iterator and read in tokens from the given stream.

Parameters:

text - text represented by the tokens

stream - stream of tokens from the text

Throws:

IOException - If something goes wrong reading from 'stream'

BasicWordIter

protected BasicWordIter()

Do-nothing constructor - should only be used by derived classes that perform their own initialization.

Method Detail

clone

public Object clone()

Description copied from interface: WordIter

Make an exact, independent, copy of this iterator

Specified by:

clone in interface WordIter

Overrides:

clone in class Object

next

public boolean next(boolean force)

Description copied from interface: WordIter

Advance to the next word. If 'force' is set, ignore any section boundary between this word and the next.

Specified by:

next in interface WordIter

Parameters:

force - true to ignore section boundaries

Returns:

true if there was another word to advance to, false if we've reached then end (or, if 'force' is false, a section boundary).

prev

public boolean prev(boolean force)

Description copied from interface: WordIter

Back up to the previous word. If 'force' is set, ignore any section boundary between this word and the previous.

Specified by:

prev in interface WordIter

Parameters:

force - true to ignore section boundaries

Returns:

true if there was room to back up, false if we've reached the start (or, if 'force' is false, a section boundary).

seekFirst

public void seekFirst(int targetPos,
                      boolean force)

Description copied from interface: WordIter

Reposition the iterator at the first word whose position is greater than or equal to 'wordPos'.

Specified by:

seekFirst in interface WordIter

Parameters:

targetPos - Position to seek to

force - true to ignore section boundaries

seekLast

public void seekLast(int targetPos,
                     boolean force)

Description copied from interface: WordIter

Reposition the iterator at the last word whose position is less than or equal to 'wordPos'.

Specified by:

seekLast in interface WordIter

Parameters:

targetPos - Position to seek to

force - true to ignore section boundaries

getPos

public MarkPos getPos(int startOrEnd)

Description copied from interface: WordIter

Retrieve the start or end of the current position.

Specified by:

getPos in interface WordIter

Parameters:

startOrEnd - FIELD_START for the very start of the field; TERM_START for the first character of the word; TERM_END for the last character of the word; TERM_END_PLUS for the last character plus any trailing punctuation and/or spaces; FIELD_END for the very last end of the field.

getPos

public void getPos(MarkPos pos,
                   int startOrEnd)

Description copied from interface: WordIter

Replace the position within a MarkPos created by WordIter.getPos(int) using the iterator's current position.

Specified by:

getPos in interface WordIter

startOrEnd - FIELD_START for the very start of the field; TERM_START for the first character of the word; TERM_END for the last character of the word; TERM_END_PLUS for the last character plus any trailing punctuation and/or spaces; FIELD_END for the very last end of the field.

term

public final String term()

Description copied from interface: WordIter

Retrieve the text of the term at the current position

Specified by:

term in interface WordIter