Looking into this I noticed another strange thing. Look at the
following example:
SerialBlob blob = new SerialBlob(new byte[255]);
blob.setBytes(1, new byte[]{1}, 0, 1); // works fine
blob.setBytes(1, new byte[]{}, 0, 1); // throws SerialException
the third line throws SerialException with the following message on RI:
javax.sql.rowset.serial.SerialException: Invalid OffSet. Cannot have
combined offset and length that is greater that the Blob buffer
It says that the blob buffer is too small, but it is large in fact!
The only difference with the second line is that the bytes array
became too small. So this message is invalid.
I think that the check of the form ((pos - 1+ length) <=
this.length()) is simply missing in RI, which results in the
ArrayIndexOutOfBoundsException's.
+1 for having this check and throwing SerialException instead of
following RI in this case.
On 12/18/06, Andrew Zhang <[EMAIL PROTECTED]> wrote:
Hi guys,
It's SerialBlob again. It's the third time to ask similar question about
SerialBlob class. :)
Let's take a look at the spec of setBytes(long pos,byte [] bytes, int
offset, int length). Throws SerialException - if there is an error
accessing the BLOB value; if an invalid position is set; if an invalid
offset value is set; if number of bytes to be written is greater than the
SerialBlob length; or the combined values of the length and offset is
greater than the Blob buffer
As my understanding, the tortuous words shows that setBytes should throw
SerialException if there's any array index outbound. But following code
shows that RI's behaviour looks weird:
public void testSetBytes() throws Exception {
byte[] buf = { 1, 2, 3, 4, 5, 6, 7, 8 };
byte[] theBytes = { 9, 9, 9 };
SerialBlob serialBlob = new SerialBlob(buf);
serialBlob.setBytes(7, theBytes); // ArrayIndexOutOfBoundsException
serialBlob.setBytes(7, theBytes, 0, 3); //
ArrayIndexOutOfBoundsException
serialBlob.setBytes(7, theBytes, 0, 10); // SerialException
}
Let's look at the spec again, what does "the combined values of the length
and offset is greater than the Blob buffer " mean? The previous sentence
already says "if number of bytes to be written (length) is greater than the
SerialBlob length(Blob buffer)".
The spec of another similar method setBytes(long pos, byte[] bytes) looks
more interesting:
SerialException - if there is an error accessing the BLOB value; or if an
invalid position is set; if an invalid offset value is set
But who can tell me what does "if an invalid offset value is set" mean? :-)
The SerialBlob class looks scary to me. What shall we do for setBytes?
Follow RI or always throw SerialException for invalid array index?
Personally I prefer to the latter one, and if it breaks any existing
application or fails TCK tests later, then let's fix it. Any
suggestions/comments? Thanks in advance!
--
Best regards,
Andrew Zhang
