[jbosscache-dev] Re: Any reason not to use ExposedByteArrayOutputStream instead of ByteArrayOutputStream ?
Manik Surtani wrote:
cc'ing JBC-dev.
The stream looks good, except that getting the raw buffer would mean
that the buffer returned would "almost certainly be longer than the
data written to it" (quoted from Brian's excellent javadocs). Bela,
how would JGroups behave with this? Would it attempt to stream the
entire buffer, including uninitialized values?
Yes, good point, this is not good ! You would have to return an
org.jgroups.util.Buffer which has the byte[] buffer but also offset and
length:
public class Buffer {
private final byte[] buf;
private final int offset;
private final int length;
public Buffer(byte[] buf, int offset, int length) {
this.buf=buf;
this.offset=offset;
this.length=length;
}
public byte[] getBuf() {
return buf;
}
public int getOffset() {
return offset;
}
public int getLength() {
return length;
}
public Buffer copy() {
byte[] new_buf=buf != null? new byte[length] : null;
int new_length=new_buf != null? new_buf.length : 0;
if(new_buf != null)
System.arraycopy(buf, offset, new_buf, 0, length);
return new Buffer(new_buf, 0, new_length);
}
public String toString() {
StringBuilder sb=new StringBuilder();
sb.append(length).append(" bytes");
if(offset > 0)
sb.append(" (offset=").append(offset).append(")");
return sb.toString();
}
}
In addition, I would have to change Marshaller to use a Buffer :
public interface Marshaller {
*Buffer* objectToByteBuffer(Object obj) throws Exception;
Object objectFromByteBuffer(*Buffer* buf) throws Exception;
}
This should have far-reaching consequences as I'm not aware of anyone
else but JBossCache to use Marshaller. Or maybe, to be on the safe side,
I could create a Marshaller2 so existing code doesn't break (extending
Marshaller)... http://jira.jboss.com/jira/browse/JGRP-796That should
Will need to see how this gets de-serialized as well. Also, since
all
cacheloaders use the same marshaller, will need to see how they deal
with this as well. Any code that relies on buf.length may end up at
best writing unnecessary data and at worst breaking when deserializing.
That
shouldn't be an issue because your JBC marshalling code creates
local variables, and doesn't reuse ByteArrayOutputStream instances
--
Bela Ban
Lead JGroups / Clustering Team
JBoss - a division of Red Hat