Ok thanks, this makes sense. It's safe to use for the same SortedDocValues
instance until the method is called again. I think changing the javadoc to
the following will help clear up the confusion:
/** Retrieves the value for the specified ordinal. The returned
* {@link BytesRef} may be re-used across calls on the same instance
to the {@link #lookupOrd(int)}
* so make sure to {@link BytesRef#deepCopyOf(BytesRef) copy it} if you want
* to keep it around.
* @param ord ordinal to lookup (must be >= 0 and < {@link
#getValueCount()})
* @see #ordValue()
*/
I can make this change if others agree.
Joel Bernstein
http://joelsolr.blogspot.com/
On Thu, May 14, 2020 at 4:37 PM Michael McCandless <
[email protected]> wrote:
> Hi Joel,
>
> You should trust the javadocs.
>
> Looking at our default Codec on master (Lucene84Codec), and at its default
> doc values implementation (Lucene80DocValuesProducer), it is clearly
> reusing the private "BytesRef term" instance.
>
> If your code is fully consuming this BytesRef before calling any other
> methods on the same SortedDocValues instance, you can safely reuse it for
> that duration.
>
> But if you want to call methods on that same SortedDocValues and continue
> using the previous BytesRef, you'll need to make a copy.
>
> Maybe improve the javadocs?
>
> Mike McCandless
>
> http://blog.mikemccandless.com
>
>
> On Thu, May 14, 2020 at 4:12 PM Joel Bernstein <[email protected]> wrote:
>
>> In the SortedDocValues.lookupOrd documentation it says that a deep copy is
>> needed for the returned BytesRef. I wanted to verify that this was actually
>> true. I'm
>>
>> trying to see a way that this BytesRef could be safely reused by the API but
>> I don't see one. Is there actually an implementation of lookupOrd that
>> somehow reuses the
>>
>> same BytesRef between invocations. The java doc is copied below:
>>
>> Thanks!
>>
>> /** Retrieves the value for the specified ordinal. The returned
>> * {@link BytesRef} may be re-used across calls to {@link #lookupOrd(int)}
>> * so make sure to {@link BytesRef#deepCopyOf(BytesRef) copy it} if you want
>> * to keep it around.
>> * @param ord ordinal to lookup (must be >= 0 and < {@link
>> #getValueCount()})
>> * @see #ordValue()
>> */
>> public abstract BytesRef lookupOrd(int ord) throws IOException;
>>
>>
>>
>> Joel Bernstein
>> http://joelsolr.blogspot.com/
>>
>
