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From "Arun Thomas" <arun.tho...@paybytouch.com>
Subject RE: [lang] [Bug 22692] - StringUtils.split ignores empty items
Date Fri, 14 Nov 2003 23:30:52 GMT
I'm a bit confused (should have expressed this in earlier comments) on the importance of whitespace.
 Why is it so important?  As far as I can see, what's needs to be identified for the tokenization
is:

	token separator                 
		separates tokens in the string
      non-separated region delimiter  
		begins/ends a portion of the string to be treated as one token
	escape
		used in such a delimited region to remove the "special" nature of a delimiter or escape

Also, is there a reason that any of these should be constrained to characters.  (I speak from
an interface perspective.)  There might be good reasons (performance or otherwise) for particular
implementations to handle only characters, etc.  

-AMT

-----Original Message-----
From: Inger, Matthew [mailto:inger@Synygy.com] 
Sent: Friday, November 14, 2003 2:46 PM
To: 'Jakarta Commons Developers List'
Subject: RE: [lang] [Bug 22692] - StringUtils.split ignores empty items


I see what you mean.  It appears, as robust as CharSet it, is does way too much, and is slow
for what we need it for.

I'm going back to DelimiterSet, but rather than an interface, it will be an inner class with
several constructors:

	public DelimiterSet(char[]);
      public DelimiterSet(String);
      public DelimiterSet(char);

and two useful methods:

	public boolean contains(char);
      public char[] getChars();

This will be an immutable object.  The
constructor sorts the character array
using Arrays.sort, and the contains method
uses Arrays.binarySearch.  This should give
us a pretty efficient algorithm for the
contains method.  There's also a predefined
whitespace delimiter set "WHITESPACE_DELIMITERSET"
so people don't have to construct their own
all the time.

-----Original Message-----
From: Stephen Colebourne [mailto:scolebourne@btopenworld.com]
Sent: Friday, November 14, 2003 5:26 PM
To: Jakarta Commons Developers List
Subject: Re: [lang] [Bug 22692] - StringUtils.split ignores empty items


An interesting idea, although the performance would be very poor without some effort in the
CharSet class. Stephen

From: "Todd V. Jonker" <todd@consciouscode.com>
> Or just use lang.CharSet
>
>
> On Fri, 14 Nov 2003 16:58:45 -0500, "Inger, Matthew" 
> <inger@Synygy.com>
> said:
> > What about an interface:
> >
> > public class DelimitedTokenizer {
> >
> >    public static interface DelimiterSet {
> >        public boolean isDelimiter(char c);
> >    }
> > }
> >
> > and having the ability to pass in this
> > interface.  Of course, we'd still have a
> > single char version as well, so someone
> > might pass either a single char or an implementation
> > of this interface as the delimiter.  I suppose I could
> > do the same thing for quotes, but i find that less useful.
>
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