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From Raghu Angadi <rang...@yahoo-inc.com>
Subject Re: Problem with InputStream.skip()
Date Tue, 29 May 2007 22:34:18 GMT

We should force subclasses of FSInputStream to implement skip if skip is 
  expected to be used. Only way I could think of achieving is to define

long skip(long len)  throws IOException {
    throw new IOException("Subclasses of FSInputStream should implement 
skip");
}

This makes sense for all the current FSInputStreams. But not sure if 
there is any way for subclasses to call InputStream.skip() is that makes 
sense.

Raghu.

Doug Cutting wrote:
> Raghu Angadi wrote:
>> Also, reading from block supports 'real skip', ie, it does not check 
>> checksum if an entire checksum block (usually 512 bytes) falls within 
>> the skip range. Another reason to implement our own skip.
> 
> Yes, I don't see an alternative to implementing skip ourselves.  The 
> optimization in InputStream#skip(), of using a static buffer, requires 
> this.  Hopefully this method, like much of the checksum code, will be 
> shared between the generic ChecksumFileSystem and DFS's optimized 
> checksum implementation.
> 
> Doug


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