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  1. JDK
  2. JDK-4997655

(bf) CharBuffer.slice() on wrapped CharSequence results in wrong position()

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P3
    • Resolution: Fixed
    • Affects Version/s: 1.4.2
    • Fix Version/s: 6
    • Component/s: core-libs
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      b51
    • CPU:
      x86
    • OS:
      linux

      Description

      Name: rmT116609 Date: 02/19/2004


      FULL PRODUCT VERSION :
      java version "1.4.2_03"
      Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_03-b02)
      Java HotSpot(TM) Client VM (build 1.4.2_03-b02, mixed mode)


      ADDITIONAL OS VERSION INFORMATION :
      Linux ventana 2.4.22-1.2115.nptl #1 Wed Oct 29 15:42:51 EST 2003 i686 i686 i386 GNU/Linux


      A DESCRIPTION OF THE PROBLEM :
      As per javadoc, CharBuffer.slice() should return a "new buffer will start at this buffer's current position" and " The new buffer's position will be zero." The CharBuffer returned on the a call to CharBuffer.wrap( CharSequence ) appears to be the StringCharBuffer which appears to have a broken slice implementation. Slice in this case appears to return the same CharBuffer as would be returned via duplicate(): position() is same as original buffer.

      See test case below.



      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      (Test case output desired):
      Slice 1 position (fixed): 0
      Slice 2 position (correct): 0

      ACTUAL -
      Actual test case output:
      Slice 1 position (bug): 3
      Slice 2 position (correct): 0


      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      import java.nio.*;

      public class slicebug
      {
          public static void main( String[] args )
          {
              String in = "foobar";

              // This version of wrap appears to internally use a
              // StringCharBuffer, which has the problem:
              CharBuffer buff1 = CharBuffer.wrap( in );
              buff1.position( 3 );
              CharBuffer slice1 = buff1.slice();

              // Position of slice should be 0, but is 3 instead:
              System.out.println( "Slice 1 position (bug): "
                                  + slice1.position() );

              // Demonstrate workaround by copying to a char[] instead (and
              // thus avoiding StringCharBuffer.
              CharBuffer buff2 = CharBuffer.wrap( in.toCharArray() );
              buff2.position( 3 );
              CharBuffer slice2 = buff2.slice();
              System.out.println( "Slice 2 position (correct): "
                                  + slice2.position() );
          }
      }
      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      Copy sequence to char[] as demonstrated in test case above. However this has copy performance penalty.
      (Incident Review ID: 235819)
      ======================================================================

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              Assignee:
              sjiang Shanliang Jiang (Inactive)
              Reporter:
              rmandalasunw Ranjith Mandala (Inactive)
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