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From "Uwe Schindler" <...@thetaphi.de>
Subject Problem with CharStream and Tokenizers with custom reset(Reader) method
Date Thu, 10 Sep 2009 14:54:26 GMT
When reviewing the new CharStream code added to Tokenizers, I found a
serious problem with backwards compatibility and other Tokenizers, that do
not override reset(CharStream).

The problem is, that e.g. CharTokenizer only overrides reset(Reader):

  public void reset(Reader input) throws IOException {
    super.reset(input);
    bufferIndex = 0;
    offset = 0;
    dataLen = 0;
  }

If you reset such a Tokenizer with another CharStream (not a Reader), this
method will never be called and breaking the whole Tokenizer.

As CharStream extends Reader, I propose to remove this reset(CharStream
method) and simply do an instanceof check to detect if the supplied Reader
is no CharStream and wrap it. We could also remove the extra ctor (because
most Tokenizers have no support for passing CharStreams). If the ctor also
checks with instanceof and warps as needed the code is backwards compatible
and we do not need to add additional ctors in subclasses.

As this instanceof check is always done in CharReader.get() why not remove
ctor(CharStream) and reset(CharStream) completely?

Any thoughts?

I would like to fix this somehow before RC4, I', sorry :(

Uwe

-----
Uwe Schindler
H.-H.-Meier-Allee 63, D-28213 Bremen
http://www.thetaphi.de
eMail: uwe@thetaphi.de




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