On Sep 12, 2008, at 12:55 AM, Antony Bowesman wrote:
There was a message from Kirk Roberts, 18/4/2007 - MultiSearcher vs
MultiReader
Grant mentioned the visibility of the readerIndex() method in
MultiReader, but nothing seems ever came of it.
Kirk never followed up, AFAICT.
Is there any reason why the following could not be put into
MultiReader? Something like this seems necessary when handling
multiple indices to solve the BitSet caching issue I raised on the
user thread.
It's slightly more efficient for a Filter implementation bits()
method to know these reader numbers in the filter (as the doc id
always seems to increment) rather than delegating back to the reader
to resolve it each call. However, it gives useful utility methods
for doing so, and gives freedom to the underlying implementation in
case that needs to change.
Antony
/** Fetches the IndexReader instance where the specified document
exists
* @param n the MultiReader document number
* @return the reader index
*/
public int readerIndex(int n) { // find reader for doc n:
return MultiSegmentReader.readerIndex(n, this.starts,
this.subReaders.length);
}
/** Fetches the document number in the specified reader for the
given document
number.
* @param i the reader index obtained from [EMAIL PROTECTED] #readerIndex(int)}
* @param n the MultiReader document number
* @return the mapped document number
*/
public int id(int i, int n) { // find true doc for doc n:
return n - this.starts[i];
}
/** Fetches the document number in the specified reader for the
given document
number.
* @param n the MultiReader document number
* @return the mapped document number
*/
public int id(int n) { // find true doc for doc n:
return n - this.starts[readerIndex(n)];
}
Is the readerIndex being public all that useful, though? Would it
make sense to just add the last id method here? What other uses for
the readerIndex() is there?
-Grant
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