Looks like a bug to me.
Can you file a JIRA ticket?
Thanks!
On 8/29/11 1:24 PM, "Yang" <teddyyyy...@gmail.com> wrote:
>if I read on a empty file with BinaryDecoder, I get EOF, good,
>
>but with the current code, if I read it again with the same decoder, I
>get a IndexOutofBoundException, not EOF.
>
>it seems that always giving EOF should be a more desirable behavior.
>
>you can see from this test code:
>
>import static org.junit.Assert.assertEquals;
>
>import java.io.IOException;
>
>import org.apache.avro.specific.SpecificRecord;
>import org.junit.Test;
>
>import myavro.Apple;
>
>import java.io.File;
>import java.io.FileInputStream;
>import java.io.FileNotFoundException;
>import java.io.FileOutputStream;
>import java.io.InputStream;
>import java.io.OutputStream;
>
>import org.apache.avro.io.Decoder;
>import org.apache.avro.io.DecoderFactory;
>import org.apache.avro.io.Encoder;
>import org.apache.avro.io.EncoderFactory;
>import org.apache.avro.specific.SpecificDatumReader;
>import org.apache.avro.specific.SpecificDatumWriter;
>
>class MyWriter {
>
> SpecificDatumWriter<SpecificRecord> wr;
> Encoder enc;
> OutputStream ostream;
>
> public MyWriter() throws FileNotFoundException {
> wr = new SpecificDatumWriter<SpecificRecord>(new
>Apple().getSchema());
> ostream = new FileOutputStream(new File("/tmp/testavro"));
> enc = EncoderFactory.get().binaryEncoder(ostream, null);
> }
>
> public synchronized void dump(SpecificRecord event) throws
>IOException {
> wr.write(event, enc);
> enc.flush();
> }
>
>}
>
>class MyReader {
>
> SpecificDatumReader<SpecificRecord> rd;
> Decoder dec;
> InputStream istream;
>
> public MyReader() throws FileNotFoundException {
> rd = new SpecificDatumReader<SpecificRecord>(new
>Apple().getSchema());
> istream = new FileInputStream(new File("/tmp/testavro"));
> dec = DecoderFactory.get().binaryDecoder(istream, null);
> }
>
> public synchronized SpecificRecord read() throws IOException {
> Object r = rd.read(null, dec);
> return (SpecificRecord) r;
> }
>
>}
>
>public class AvroWriteAndReadSameTime {
> @Test
> public void testWritingAndReadingAtSameTime() throws Exception {
>
> MyWriter dumper = new MyWriter();
> final Apple apple = new Apple();
> apple.taste = "sweet";
> dumper.dump(apple);
>
> final MyReader rd = new MyReader();
> rd.read();
>
>
> try {
> rd.read();
> } catch (Exception e) {
> e.printStackTrace();
> }
>
> // the second one somehow generates a NPE, we hope to get EOF...
> try {
> rd.read();
> } catch (Exception e) {
> e.printStackTrace();
> }
>
> }
>}
>
>
>
>
>
>the issue is in BinaryDecoder.readInt(), right now even when it hits
>EOF, it still advances the pos pointer.
>all the other APIs (readLong readFloat ...) do not do this. changing
>to the following makes it work:
>
>
> @Override
> public int readInt() throws IOException {
> ensureBounds(5); // won't throw index out of bounds
> int len = 1;
> int b = buf[pos] & 0xff;
> int n = b & 0x7f;
> if (b > 0x7f) {
> b = buf[pos + len++] & 0xff;
> n ^= (b & 0x7f) << 7;
> if (b > 0x7f) {
> b = buf[pos + len++] & 0xff;
> n ^= (b & 0x7f) << 14;
> if (b > 0x7f) {
> b = buf[pos + len++] & 0xff;
> n ^= (b & 0x7f) << 21;
> if (b > 0x7f) {
> b = buf[pos + len++] & 0xff;
> n ^= (b & 0x7f) << 28;
> if (b > 0x7f) {
> throw new IOException("Invalid int encoding");
> }
> }
> }
> }
> }
> if (pos+len > limit) {
> throw new EOFException();
> }
> pos += len; //<================== CHANGE, used to be
>above the EOF throw
>
> return (n >>> 1) ^ -(n & 1); // back to two's-complement
> }
