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https://issues.apache.org/jira/browse/HBASE-10564?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13903979#comment-13903979
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Feng Honghua commented on HBASE-10564:
--------------------------------------
It would be better the code owner who first introduced this method helps
confirm that this method is meant to be used somewhere, by design it's meant to
be used where only positive random integer is allowed.
> HRegionServer.nextLong should be removed since it's not used anywhere, or
> should be used somewhere it meant to
> --------------------------------------------------------------------------------------------------------------
>
> Key: HBASE-10564
> URL: https://issues.apache.org/jira/browse/HBASE-10564
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Reporter: Feng Honghua
> Assignee: Feng Honghua
> Priority: Minor
> Attachments: HBASE-10564-trunk_v1.patch
>
>
> HRegionServer has its own nextLong method as below:
> {code}
> /**
> * Generate a random positive long number
> *
> * @return a random positive long number
> */
> protected long nextLong() {
> long n = rand.nextLong();
> if (n == 0) {
> return nextLong();
> }
> if (n < 0) {
> n = -n;
> }
> return n;
> }
> {code}
> # It's never called anywhere, if we can ensure it's really useless, it should
> be removed
> # Looks likely below should use *nextLong* rather than *rand.nextLong*(but
> not sure):
> {code}
> protected long addScanner(RegionScanner s, HRegion r) throws
> LeaseStillHeldException {
> long scannerId = -1;
> while (true) {
> scannerId = Math.abs(rand.nextLong() << 24) ^ startcode;
> String scannerName = String.valueOf(scannerId);
> RegionScannerHolder existing =
> scanners.putIfAbsent(scannerName, new RegionScannerHolder(s, r));
> if (existing == null) {
> this.leases.createLease(scannerName, this.scannerLeaseTimeoutPeriod,
> new ScannerListener(scannerName));
> break;
> }
> }
> return scannerId;
> }
> {code}
> # Its implemenation would be better if
> {code}
> if (n == 0) {
> return nextLong();
> }
> {code}
> is changed to below (with better readability and (possible) less call-stacks
> by removing recursion)
> {code}
> while (n == 0) {
> n = rand.nextLong();
> }
> {code}
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