Greetings, i was purusing old mailing list emails, and stumbled onto the following email sent some time ago :)

Luckily, from a quick perusal of the code, it appears that the email still applies.

I have a question about the implementation of SymbolTable

As expected, it appears to me to that it does hashing to find a bucket, then walks the chain of pointers from the bucket to find a string that is 'equals'

Only if it doesn't exist is a new one added. All of this makes sense.

The question i have then, is why when you add an entry

public Entry(String symbol, Entry next) {
   this.symbol = symbol.intern();
   characters = new char[symbol.length()];
   symbol.getChars(0, characters.length, characters, 0);
   this.next = next;
}

does the code intern the string? Isn't the point of this class to stop pollution of the constant pool and perm gen? (besides allowing for alternate hashing?) Given that the one String that lives in the SymbolTable is returned, i would think intern is redundant.

thanks,
dave

----- Original Message ----- From: "Michael Glavassevich" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, July 24, 2005 11:57 AM
Subject: Re: Interning strategy


Elliotte Harold <[EMAIL PROTECTED]> wrote on 07/22/2005 09:35:02 PM:

Suppose I turn on interning in the parser by setting the SAX property
http://xml.org/sax/features/string-interning to true. Will Xerces simply

invoke the String.intern() method on the strings it creates or does it
do something fancier like maintaining its own pool of string constants
and reuse those?

It maintains a pool. See org.apache.xerces.util.SymbolTable, specifically
the addSymbol() methods.

--
Elliotte Rusty Harold  [EMAIL PROTECTED]
XML in a Nutshell 3rd Edition Just Published!
http://www.cafeconleche.org/books/xian3/
http://www.amazon.com/exec/obidos/ISBN=0596007647/cafeaulaitA/ref=nosim

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Michael Glavassevich
XML Parser Development
IBM Toronto Lab
E-mail: [EMAIL PROTECTED]
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