Re: Trouble with custom InputStream being used by Readers

From:
Daniele Futtorovic <da.futt.news@laposte.invalid>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 06 Aug 2008 04:28:52 +0200
Message-ID:
<g7b29q$2n9$1@registered.motzarella.org>
On 06/08/2008 02:04, Tom Anderson allegedly wrote:

On Tue, 5 Aug 2008, Chase Preuninger wrote:

Well how does any other console stop blocking so that a BufferedReader
can stop buffering? Does it just return -1 when it has more data. But
what if it acquires more later on?


I suspect, but am not certain, that Daniele is wrong about
BufferedReader's behaviour.


Might always be the case.

But:

     private static class BogusInputStream
     extends InputStream
     {
         private final int size;
         private int pos;

         public BogusInputStream(int size){
             this.size = size;
         }

         public int read()
         throws IOException
         {
             if( pos < size ){
                 pos++; return 'a';
             }
             else{
                 for(;;);
             }
         }
     }

     public static void main(String[] ss)
     throws Exception
     {
         Reader r1 = new InputStreamReader(new BogusInputStream(1<<13));
         Reader r2 = new InputStreamReader(new BogusInputStream(1<<12));

         r1.read(); // <- works

         r2.read(); // <- blocks
     }

 From which we can infer that on my machine, the sun.nio.cs.StreamDecoder
has an 8k buffer.

Granted, that's not the BufferedReader, but I think it's pretty much a
given that that infinite loop is the root of the problem. That, and not
overriding int read(byte[], int, int) or int read(char[], int, int).

--
DF.

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