Thread: [Htmlparser-developer] Method to check if TextNode is just whitespace

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htmlparser-developer

[Htmlparser-developer] Method to check if TextNode is just whitespace

From: Ian M. <ian...@gm...> - 2005-11-01 10:56:44

I was thinking it might be worthwhile adding a method to Text/TextNode
along the lines of:

boolean isWhiteSpace()

Which would return if the TextNode consisted of solely white space
characters (or was the empty String).

Now this could simply be done using String.trim().equals(""), however
that wouldn't account for:

- the non-breaking space character (#160)
- The HTML code &nbsp; (also &nbsp as Firefox/IE do)
- The HTML code &#160; (also &#160 as Firefox/IE do)

So my question is, do you think should this method should treat those
as spaces and remove/ignore them also for purposes of determining if
the TextNode is white space? Or should it only trim normal whitespace
(space, tab, carriage returns, etc).

Thanks for your advice

Ian Macfarlane

Re: [Htmlparser-developer] Method to check if TextNode is just whitespace

From: Axel <ax...@gm...> - 2005-11-02 22:07:16

On 11/1/05, Ian Macfarlane <ian...@gm...> wrote:
> I was thinking it might be worthwhile adding a method to Text/TextNode
> along the lines of:
>
> boolean isWhiteSpace()
>
> Which would return if the TextNode consisted of solely white space
> characters (or was the empty String).
>
> Now this could simply be done using String.trim().equals(""), however
> that wouldn't account for:
>
> - the non-breaking space character (#160)
> - The HTML code &nbsp; (also &nbsp as Firefox/IE do)
> - The HTML code &#160; (also &#160 as Firefox/IE do)
>
> So my question is, do you think should this method should treat those
> as spaces and remove/ignore them also for purposes of determining if
> the TextNode is white space? Or should it only trim normal whitespace
> (space, tab, carriage returns, etc).
I think, if every character (or entity converted to a
unicode-character) in the TextNode is true for
Character#isWhitespace() the boolean isWhiteSpace() should return
true;
IMO the TextNode shouldn't be trimmed automatically. Only a special
function should allow this to do.

--
Axel Kramer
http://www.plog4u.org - Wikipedia Eclipse Plugin

Re: [Htmlparser-developer] Method to check if TextNode is just whitespace

From: Ian M. <ian...@gm...> - 2005-11-03 12:44:59

Thanks for your reply,

I wasn't suggesting trimming the actual text of the text nodes
permanently, merely wondering if using the trim() method to see if the
resulting string was empty would be sufficient, or whether we should
also look for various white-space HTML entities (e.g. &tab; also) for
purposes of determining this.

Now I think about it some more, white space alone is probably what we
want to do. If we want to get things like &tab; we ought to write some
sort of method that would replace those types of HTML character
references with the actual characters, if that's feasible.

The only other question I've got - what do you all think should happen
if the contents of the text node is null? Should it return true
(because there's no characters), false (because it's not actually a
white space String) or throw a NullPointerException (which would
negate the value of this method by forcing the end-user to write lots
of code to use this method)? Can a text node ever be null without the
user changing the text ot be null?

Ian

String is immutable so String.trim().equals("") won't change the
original String object.

On 11/2/05, Axel <ax...@gm...> wrote:
> On 11/1/05, Ian Macfarlane <ian...@gm...> wrote:
> > I was thinking it might be worthwhile adding a method to Text/TextNode
> > along the lines of:
> >
> > boolean isWhiteSpace()
> >
> > Which would return if the TextNode consisted of solely white space
> > characters (or was the empty String).
> >
> > Now this could simply be done using String.trim().equals(""), however
> > that wouldn't account for:
> >
> > - the non-breaking space character (#160)
> > - The HTML code &nbsp; (also &nbsp as Firefox/IE do)
> > - The HTML code &#160; (also &#160 as Firefox/IE do)
> >
> > So my question is, do you think should this method should treat those
> > as spaces and remove/ignore them also for purposes of determining if
> > the TextNode is white space? Or should it only trim normal whitespace
> > (space, tab, carriage returns, etc).
> I think, if every character (or entity converted to a
> unicode-character) in the TextNode is true for
> Character#isWhitespace() the boolean isWhiteSpace() should return
> true;
> IMO the TextNode shouldn't be trimmed automatically. Only a special
> function should allow this to do.
>
> --
> Axel Kramer
> http://www.plog4u.org - Wikipedia Eclipse Plugin
>
>
> -------------------------------------------------------
> SF.Net email is sponsored by:
> Tame your development challenges with Apache's Geronimo App Server. Downl=
oad
> it for free - -and be entered to win a 42" plasma tv or your very own
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> _______________________________________________
> Htmlparser-developer mailing list
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> https://lists.sourceforge.net/lists/listinfo/htmlparser-developer
>

Re: [Htmlparser-developer] Method to check if TextNode is just whitespace

From: Derrick O. <Der...@Ro...> - 2005-11-03 14:28:06

Conversion of character references like &nbsp; is already performed by 
the util.Translate class.
There is no &tab; character reference as far as I'm aware (see 
http://www.w3.org/TR/REC-html40/sgml/entities.html).

Ian Macfarlane wrote:

>Thanks for your reply,
>
>I wasn't suggesting trimming the actual text of the text nodes
>permanently, merely wondering if using the trim() method to see if the
>resulting string was empty would be sufficient, or whether we should
>also look for various white-space HTML entities (e.g. &tab; also) for
>purposes of determining this.
>
>Now I think about it some more, white space alone is probably what we
>want to do. If we want to get things like &tab; we ought to write some
>sort of method that would replace those types of HTML character
>references with the actual characters, if that's feasible.
>
>The only other question I've got - what do you all think should happen
>if the contents of the text node is null? Should it return true
>(because there's no characters), false (because it's not actually a
>white space String) or throw a NullPointerException (which would
>negate the value of this method by forcing the end-user to write lots
>of code to use this method)? Can a text node ever be null without the
>user changing the text ot be null?
>
>Ian
>
>String is immutable so String.trim().equals("") won't change the
>original String object.
>
>On 11/2/05, Axel <ax...@gm...> wrote:
>  
>
>>On 11/1/05, Ian Macfarlane <ian...@gm...> wrote:
>>    
>>
>>>I was thinking it might be worthwhile adding a method to Text/TextNode
>>>along the lines of:
>>>
>>>boolean isWhiteSpace()
>>>
>>>Which would return if the TextNode consisted of solely white space
>>>characters (or was the empty String).
>>>
>>>Now this could simply be done using String.trim().equals(""), however
>>>that wouldn't account for:
>>>
>>>- the non-breaking space character (#160)
>>>- The HTML code &nbsp; (also &nbsp as Firefox/IE do)
>>>- The HTML code &#160; (also &#160 as Firefox/IE do)
>>>
>>>So my question is, do you think should this method should treat those
>>>as spaces and remove/ignore them also for purposes of determining if
>>>the TextNode is white space? Or should it only trim normal whitespace
>>>(space, tab, carriage returns, etc).
>>>      
>>>
>>I think, if every character (or entity converted to a
>>unicode-character) in the TextNode is true for
>>Character#isWhitespace() the boolean isWhiteSpace() should return
>>true;
>>IMO the TextNode shouldn't be trimmed automatically. Only a special
>>function should allow this to do.
>>
>>--
>>Axel Kramer
>>http://www.plog4u.org - Wikipedia Eclipse Plugin
>>
>>
>>-------------------------------------------------------
>>SF.Net email is sponsored by:
>>Tame your development challenges with Apache's Geronimo App Server. Download
>>it for free - -and be entered to win a 42" plasma tv or your very own
>>Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
>>_______________________________________________
>>Htmlparser-developer mailing list
>>Htm...@li...
>>https://lists.sourceforge.net/lists/listinfo/htmlparser-developer
>>
>>    
>>
>
>
>-------------------------------------------------------
>SF.Net email is sponsored by:
>Tame your development challenges with Apache's Geronimo App Server. Download
>it for free - -and be entered to win a 42" plasma tv or your very own
>Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
>_______________________________________________
>Htmlparser-developer mailing list
>Htm...@li...
>https://lists.sourceforge.net/lists/listinfo/htmlparser-developer
>
>  
>

Re: [Htmlparser-developer] Method to check if TextNode is just whitespace

From: Ian M. <ian...@gm...> - 2005-11-03 14:57:22

> Conversion of character references like &nbsp; is already performed by th=
e util.Translate class.
Oh good! No need for me to write it then :)

> There is no &tab; character reference as far as I'm aware
You're right, I just guessed a whitespace entity name, typed it into
Google and found references to it. Sorry, I ought to have checked it
out a bit better first.

Derrick, for a isWhiteSpace() method, what do you think it ought to do
when the String is null?

Ian

On 11/3/05, Derrick Oswald <Der...@ro...> wrote:
> Conversion of character references like &nbsp; is already performed by
> the util.Translate class.
> There is no &tab; character reference as far as I'm aware (see
> http://www.w3.org/TR/REC-html40/sgml/entities.html).
>
> Ian Macfarlane wrote:
>
> >Thanks for your reply,
> >
> >I wasn't suggesting trimming the actual text of the text nodes
> >permanently, merely wondering if using the trim() method to see if the
> >resulting string was empty would be sufficient, or whether we should
> >also look for various white-space HTML entities (e.g. &tab; also) for
> >purposes of determining this.
> >
> >Now I think about it some more, white space alone is probably what we
> >want to do. If we want to get things like &tab; we ought to write some
> >sort of method that would replace those types of HTML character
> >references with the actual characters, if that's feasible.
> >
> >The only other question I've got - what do you all think should happen
> >if the contents of the text node is null? Should it return true
> >(because there's no characters), false (because it's not actually a
> >white space String) or throw a NullPointerException (which would
> >negate the value of this method by forcing the end-user to write lots
> >of code to use this method)? Can a text node ever be null without the
> >user changing the text ot be null?
> >
> >Ian
> >
> >String is immutable so String.trim().equals("") won't change the
> >original String object.
> >
> >On 11/2/05, Axel <ax...@gm...> wrote:
> >
> >
> >>On 11/1/05, Ian Macfarlane <ian...@gm...> wrote:
> >>
> >>
> >>>I was thinking it might be worthwhile adding a method to Text/TextNode
> >>>along the lines of:
> >>>
> >>>boolean isWhiteSpace()
> >>>
> >>>Which would return if the TextNode consisted of solely white space
> >>>characters (or was the empty String).
> >>>
> >>>Now this could simply be done using String.trim().equals(""), however
> >>>that wouldn't account for:
> >>>
> >>>- the non-breaking space character (#160)
> >>>- The HTML code &nbsp; (also &nbsp as Firefox/IE do)
> >>>- The HTML code &#160; (also &#160 as Firefox/IE do)
> >>>
> >>>So my question is, do you think should this method should treat those
> >>>as spaces and remove/ignore them also for purposes of determining if
> >>>the TextNode is white space? Or should it only trim normal whitespace
> >>>(space, tab, carriage returns, etc).
> >>>
> >>>
> >>I think, if every character (or entity converted to a
> >>unicode-character) in the TextNode is true for
> >>Character#isWhitespace() the boolean isWhiteSpace() should return
> >>true;
> >>IMO the TextNode shouldn't be trimmed automatically. Only a special
> >>function should allow this to do.
> >>
> >>--
> >>Axel Kramer
> >>http://www.plog4u.org - Wikipedia Eclipse Plugin
> >>
> >>
> >>-------------------------------------------------------
> >>SF.Net email is sponsored by:
> >>Tame your development challenges with Apache's Geronimo App Server. Dow=
nload
> >>it for free - -and be entered to win a 42" plasma tv or your very own
> >>Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
> >>_______________________________________________
> >>Htmlparser-developer mailing list
> >>Htm...@li...
> >>https://lists.sourceforge.net/lists/listinfo/htmlparser-developer
> >>
> >>
> >>
> >
> >
> >-------------------------------------------------------
> >SF.Net email is sponsored by:
> >Tame your development challenges with Apache's Geronimo App Server. Down=
load
> >it for free - -and be entered to win a 42" plasma tv or your very own
> >Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
> >_______________________________________________
> >Htmlparser-developer mailing list
> >Htm...@li...
> >https://lists.sourceforge.net/lists/listinfo/htmlparser-developer
> >
> >
> >
>
>
>
> -------------------------------------------------------
> SF.Net email is sponsored by:
> Tame your development challenges with Apache's Geronimo App Server. Downl=
oad
> it for free - -and be entered to win a 42" plasma tv or your very own
> Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
> _______________________________________________
> Htmlparser-developer mailing list
> Htm...@li...
> https://lists.sourceforge.net/lists/listinfo/htmlparser-developer
>

Re: [Htmlparser-developer] Method to check if TextNode is just whitespace

From: Derrick O. <Der...@Ro...> - 2005-11-04 12:48:31

IMHO, the text shouldn't ever be null, but if it is, toHtml() would 
(should?) return an empty string, so isWhitespace() should also return true.

Ian Macfarlane wrote:

>>Conversion of character references like &nbsp; is already performed by the util.Translate class.
>>    
>>
>Oh good! No need for me to write it then :)
>
>  
>
>>There is no &tab; character reference as far as I'm aware
>>    
>>
>You're right, I just guessed a whitespace entity name, typed it into
>Google and found references to it. Sorry, I ought to have checked it
>out a bit better first.
>
>Derrick, for a isWhiteSpace() method, what do you think it ought to do
>when the String is null?
>
>Ian
>
>On 11/3/05, Derrick Oswald <Der...@ro...> wrote:
>  
>
>>Conversion of character references like &nbsp; is already performed by
>>the util.Translate class.
>>There is no &tab; character reference as far as I'm aware (see
>>http://www.w3.org/TR/REC-html40/sgml/entities.html).
>>
>>Ian Macfarlane wrote:
>>
>>    
>>
>>>Thanks for your reply,
>>>
>>>I wasn't suggesting trimming the actual text of the text nodes
>>>permanently, merely wondering if using the trim() method to see if the
>>>resulting string was empty would be sufficient, or whether we should
>>>also look for various white-space HTML entities (e.g. &tab; also) for
>>>purposes of determining this.
>>>
>>>Now I think about it some more, white space alone is probably what we
>>>want to do. If we want to get things like &tab; we ought to write some
>>>sort of method that would replace those types of HTML character
>>>references with the actual characters, if that's feasible.
>>>
>>>The only other question I've got - what do you all think should happen
>>>if the contents of the text node is null? Should it return true
>>>(because there's no characters), false (because it's not actually a
>>>white space String) or throw a NullPointerException (which would
>>>negate the value of this method by forcing the end-user to write lots
>>>of code to use this method)? Can a text node ever be null without the
>>>user changing the text ot be null?
>>>
>>>Ian
>>>
>>>String is immutable so String.trim().equals("") won't change the
>>>original String object.
>>>
>>>On 11/2/05, Axel <ax...@gm...> wrote:
>>>
>>>
>>>      
>>>
>>>>On 11/1/05, Ian Macfarlane <ian...@gm...> wrote:
>>>>
>>>>
>>>>        
>>>>
>>>>>I was thinking it might be worthwhile adding a method to Text/TextNode
>>>>>along the lines of:
>>>>>
>>>>>boolean isWhiteSpace()
>>>>>
>>>>>Which would return if the TextNode consisted of solely white space
>>>>>characters (or was the empty String).
>>>>>
>>>>>Now this could simply be done using String.trim().equals(""), however
>>>>>that wouldn't account for:
>>>>>
>>>>>- the non-breaking space character (#160)
>>>>>- The HTML code &nbsp; (also &nbsp as Firefox/IE do)
>>>>>- The HTML code &#160; (also &#160 as Firefox/IE do)
>>>>>
>>>>>So my question is, do you think should this method should treat those
>>>>>as spaces and remove/ignore them also for purposes of determining if
>>>>>the TextNode is white space? Or should it only trim normal whitespace
>>>>>(space, tab, carriage returns, etc).
>>>>>
>>>>>
>>>>>          
>>>>>
>>>>I think, if every character (or entity converted to a
>>>>unicode-character) in the TextNode is true for
>>>>Character#isWhitespace() the boolean isWhiteSpace() should return
>>>>true;
>>>>IMO the TextNode shouldn't be trimmed automatically. Only a special
>>>>function should allow this to do.
>>>>
>>>>--
>>>>Axel Kramer
>>>>http://www.plog4u.org - Wikipedia Eclipse Plugin
>>>>
>>>>
>>>>-------------------------------------------------------
>>>>SF.Net email is sponsored by:
>>>>Tame your development challenges with Apache's Geronimo App Server. Download
>>>>it for free - -and be entered to win a 42" plasma tv or your very own
>>>>Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
>>>>_______________________________________________
>>>>Htmlparser-developer mailing list
>>>>Htm...@li...
>>>>https://lists.sourceforge.net/lists/listinfo/htmlparser-developer
>>>>
>>>>
>>>>
>>>>        
>>>>
>>>-------------------------------------------------------
>>>SF.Net email is sponsored by:
>>>Tame your development challenges with Apache's Geronimo App Server. Download
>>>it for free - -and be entered to win a 42" plasma tv or your very own
>>>Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
>>>_______________________________________________
>>>Htmlparser-developer mailing list
>>>Htm...@li...
>>>https://lists.sourceforge.net/lists/listinfo/htmlparser-developer
>>>
>>>
>>>
>>>      
>>>
>>
>>-------------------------------------------------------
>>SF.Net email is sponsored by:
>>Tame your development challenges with Apache's Geronimo App Server. Download
>>it for free - -and be entered to win a 42" plasma tv or your very own
>>Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
>>_______________________________________________
>>Htmlparser-developer mailing list
>>Htm...@li...
>>https://lists.sourceforge.net/lists/listinfo/htmlparser-developer
>>
>>    
>>
>
>
>-------------------------------------------------------
>SF.Net email is sponsored by:
>Tame your development challenges with Apache's Geronimo App Server. Download
>it for free - -and be entered to win a 42" plasma tv or your very own
>Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
>_______________________________________________
>Htmlparser-developer mailing list
>Htm...@li...
>https://lists.sourceforge.net/lists/listinfo/htmlparser-developer
>
>  
>