Name: gm110360 Date: 09/09/2002


FULL PRODUCT VERSION :
java version "1.4.1-rc"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1-rc-b19)
Java HotSpot(TM) Client VM (build 1.4.1-rc-b19, mixed mode)


FULL OPERATING SYSTEM VERSION :

Microsoft Windows 2000 [Version 5.00.2195] (sp2)



A DESCRIPTION OF THE PROBLEM :
bug: InputStreamReader doesn't call CharsetDecoder.flush
when it reaches the end of stream.

This is a problem for decoders which keep internal state and
need to
know when the end of stream is reached to flush the final
characters to the char buffer.

See CharsetDecoder
http://java.sun.com/j2se/1.4/docs/api/java/nio/charset/CharsetDecoder.html

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
  To verify this problem, run the code below. It uses a very
simple Charset that is instrumented to show calls to
implReset and implFlush.

EXPECTED VERSUS ACTUAL BEHAVIOR :
Actual: In j2se1.4.1rc1, I get the following output.
Decoder receives call to implReset at end of input stream.

Expected: Decoder should receive a call to implFlush at end
of input stream.

    <pre>

Testing Encoder...
before start: EncoderState: reset=true, flushed=true
between write and flush: EncoderState: reset=false,
flushed=false
after flush: EncoderState: reset=false, flushed=false
flushed encoder
after close: EncoderState: reset=false, flushed=true

Testing Decoder...
before start: DecoderState: reset=true, flushed=true
after read: DecoderState: reset=false, flushed=false
after read: DecoderState: reset=false, flushed=false
after read: DecoderState: reset=false, flushed=false
reset decoder <-----???
after done: DecoderState: reset=true, flushed=false
     </pre>


ERROR MESSAGES/STACK TRACES THAT OCCUR :
This stack trace shows that reset is being called from read.

java.lang.Exception: Stack trace
at java.lang.Thread.dumpStack(Thread.java:1071)
at
TestReaderFlushesCharset$TestDecoder.implReset(TestReaderFlushesCharset.java:123)
at java.nio.charset.CharsetDecoder.reset(CharsetDecoder.java:656)
at sun.nio.cs.StreamDecoder$CharsetSD.implRead(StreamDecoder.java:464)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:180)
at java.io.InputStreamReader.read(InputStreamReader.java:167)
at TestReaderFlushesCharset.testDecoder(TestReaderFlushesCharset.java:63)
at TestReaderFlushesCharset.main(TestReaderFlushesCharset.java:37)


REPRODUCIBILITY :
This bug can be reproduced always.

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

/** bug: InputStreamReader doesn't call CharsetDecoder.flush.

    <p>This is a problem for decoders which keep internal state and need to
    know when the end of stream is reached.

    <p>To verify this problem, run the code below.
    In j2se1.4.1rc1, I get the following output. Notice decoder
    receives call to implReset where it should receive a call to implFlush.

    <pre>

Testing Encoder...
before start: EncoderState: reset=true, flushed=true
between write and flush: EncoderState: reset=false, flushed=false
after flush: EncoderState: reset=false, flushed=false
flushed encoder
after close: EncoderState: reset=false, flushed=true

Testing Decoder...
before start: DecoderState: reset=true, flushed=true
after read: DecoderState: reset=false, flushed=false
after read: DecoderState: reset=false, flushed=false
after read: DecoderState: reset=false, flushed=false
reset decoder <-----???
after done: DecoderState: reset=true, flushed=false
     </pre>
**/

public class TestReaderFlushesCharset extends Charset{
  static TestReaderFlushesCharset testCharset = new TestReaderFlushesCharset();
  public static void main(String[] ignore) {
    testEncoder();
    testDecoder();
  }
  private static void testEncoder() {
    System.out.println("\nTesting Encoder...");
    ByteArrayOutputStream outStream = new ByteArrayOutputStream();
    TestEncoder testEncoder = (TestEncoder) testCharset.newEncoder();
    OutputStreamWriter writer = new OutputStreamWriter(outStream, testEncoder);
    try {
      System.out.println("before start: "+testEncoder.state());
      writer.write("hello world");
      System.out.println("between write and flush: "+testEncoder.state());
      writer.flush();
      System.out.println("after flush: "+testEncoder.state());
      writer.close();
      System.out.println("after close: "+testEncoder.state());
    } catch (IOException e) { e.printStackTrace(); }
  }
  private static void testDecoder() {
    System.out.println("\nTesting Decoder...");
    ByteArrayInputStream inStream = new ByteArrayInputStream
      (new byte[]{'h','i',' ','w','o','r','l','d'});
    TestDecoder testDecoder = (TestDecoder) testCharset.newDecoder();
    InputStreamReader reader = new InputStreamReader(inStream, testDecoder);
    try {
      System.out.println("before start: "+testDecoder.state());
      char[] buf = new char[3];
      while( reader.read(buf, 0, buf.length) > 0)
System.out.println("after read: "+testDecoder.state());
      System.out.println("after done: "+testDecoder.state());
    } catch (IOException e) { e.printStackTrace(); }
  }

  TestReaderFlushesCharset() { super("X-TestCharSet", new String[]{}); }
  public boolean contains(Charset cs) {
    return cs instanceof TestReaderFlushesCharset;
  }
  public CharsetEncoder newEncoder() {
    return new TestEncoder();
  }
  public CharsetDecoder newDecoder() {
    return new TestDecoder();
  }
  class TestEncoder extends CharsetEncoder {
    // some dummy internal state;
    boolean reset = true;
    boolean flushed = true;

    TestEncoder() {
      super(TestReaderFlushesCharset.this, 1.0f, 2.0f);
    }
    public String state() {
      return "EncoderState: reset="+reset+", flushed="+flushed; }

    protected void implReset() {
      reset = true;
      System.err.println("reset encoder");
    }
    protected CoderResult implFlush(ByteBuffer out) {
      flushed = true;
      System.err.println("flushed encoder");
      return CoderResult.UNDERFLOW;
    }
    protected CoderResult encodeLoop(CharBuffer in, ByteBuffer out) {
      // System.err.println("encode loop in.remaining="+in.remaining());
      while (in.hasRemaining()) {
if (!out.hasRemaining())
return CoderResult.OVERFLOW;
reset = false;
flushed = false;
out.put((byte) (in.get() & 0xff)); // test works only for latin-1.
      }
      return CoderResult.UNDERFLOW;
    }
  }
  class TestDecoder extends CharsetDecoder {
    // some dummy internal state;
    boolean reset = true;
    boolean flushed = true;

    TestDecoder() {
      super(TestReaderFlushesCharset.this, 1.0f, 1.0f);
    }
    public String state() {
      return "DecoderState: reset="+reset+", flushed="+flushed; }

    protected void implReset() {
      //Thread.dumpStack();
      reset = true;
      System.err.println("reset decoder");
    }
    protected CoderResult implFlush(CharBuffer out) {
      flushed = true;
      System.err.println("flushed decoder");
      return CoderResult.UNDERFLOW;
    }
    protected CoderResult decodeLoop(ByteBuffer in, CharBuffer out) {
      // System.err.println("decode loop in.remaining="+in.remaining());
      while (in.hasRemaining()) {
if (!out.hasRemaining())
return CoderResult.OVERFLOW;
reset = false;
flushed = false;
out.put((char) in.get()); // test works only for latin-1.
      }
      return CoderResult.UNDERFLOW;
    }
  }
}

---------- END SOURCE ----------
(Review ID: 164238)
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