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Groups > comp.lang.java.programmer > #28500

Re: byte stream vs char stream buffer

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On Sun, 11 May 2014 11:50:24 -0700, markspace
<markspace@nospam.nospam> wrote, quoted or indirectly quoted someone
who said :

>       ByteBuffer bb = ByteBuffer.allocateDirect( 64 * 1024 );
>       RandomAccessFile f = new RandomAccessFile( "blet", "rw" );
>       FileChannel fc = f.getChannel();
>       readToCapacity( fc, bb );
>       bb.flip();
>       ByteBuffer b2 = bb.slice();
>       b2.asReadOnlyBuffer();

I would like this as an example of nio. I wonder why each step is
necessary.


// sample use of NIO to read a text file very rapidly
// by Mark Space

// alloc buffer suited for direct physical I/O
ByteBuffer bb = ByteBuffer.allocateDirect( 64 * 1024 ); 

RandomAccessFile f = new RandomAccessFile( "blet", "rw" );

FileChannel fc = f.getChannel();

// A user method to consume one chunk of data
// It would have to convert bytes to chars, fretting over boundaries.
readToCapacity( fc, bb ); 

// request the next chunk of data
bb.flip();

// ? 
ByteBuffer b2 = bb.slice();  

// creates readonly version and discards
b2.asReadOnlyBuffer(); 

-- 
Roedy Green Canadian Mind Products http://mindprod.com
Young man, in mathematics you don’t understand things.
You just get used to them. 
~ John von Neumann (born: 1903-12-28 died: 1957-02-08 at age: 53)

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byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-06 23:48 -0700
  Re: byte stream vs char stream buffer Andreas Leitgeb <avl@auth.logic.tuwien.ac.at> - 2014-05-08 13:30 +0000
    Re: byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-09 09:34 -0700
      Re: byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-10 13:18 -0700
        Re: byte stream vs char stream buffer Robert Klemme <shortcutter@googlemail.com> - 2014-05-10 23:24 +0200
          Re: byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-10 16:08 -0700
            Re: byte stream vs char stream buffer Robert Klemme <shortcutter@googlemail.com> - 2014-05-11 16:02 +0200
              Re: byte stream vs char stream buffer markspace <markspace@nospam.nospam> - 2014-05-11 11:50 -0700
                Re: byte stream vs char stream buffer markspace <markspace@nospam.nospam> - 2014-05-11 12:10 -0700
                Re: byte stream vs char stream buffer Robert Klemme <shortcutter@googlemail.com> - 2014-05-11 21:34 +0200
                Re: byte stream vs char stream buffer markspace <markspace@nospam.nospam> - 2014-05-11 12:55 -0700
                Re: byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-16 16:55 -0700
                Re: byte stream vs char stream buffer markspace <markspace@nospam.nospam> - 2014-05-16 17:36 -0700
                Re: byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-16 19:52 -0700
              Re: byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-16 16:37 -0700
          Re: byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-10 17:21 -0700
            Re: byte stream vs char stream buffer Martin Gregorie <martin@address-in-sig.invalid> - 2014-05-11 09:05 +0000
              Re: byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-12 02:07 -0700
                Re: byte stream vs char stream buffer Silvio <silvio@internet.com> - 2014-05-12 12:20 +0200
                Re: byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-16 20:19 -0700
                Re: byte stream vs char stream buffer Roedy Green <see_website@mindprod.com.invalid> - 2014-05-18 05:28 -0700
                Re: byte stream vs char stream buffer Silvio <silvio@internet.com> - 2014-05-18 23:54 +0200

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