On Wed, 3 Nov 2021 17:23:51 GMT, Claes Redestad <redestad@openjdk.org> wrote:
Prompted by a request from Volkan Yazıcı I took a look at why the java.time formatters are less efficient for some common patterns than custom formatters in apache-commons and log4j. This patch reduces the gap, without having looked at the third party implementations.
When printing times: - Avoid turning integral values into `String`s before appending them to the buffer - Specialize `appendFraction` for `NANO_OF_SECOND` to avoid use of `BigDecimal`
This means a speed-up and reduction in allocations when formatting almost any date or time pattern, and especially so when including sub-second parts (`S-SSSSSSSSS`).
Much of the remaining overhead can be traced to the need to create a `DateTimePrintContext` and adjusting `Instant`s into a `ZonedDateTime` internally. We could likely also win performance by specializing some common patterns.
Testing: tier1-3
Claes Redestad has updated the pull request incrementally with one additional commit since the last revision:
Minor cleanup
test/jdk/java/time/test/java/time/format/TestFractionPrinterParser.java line 80:
78: 79: /** 80: * Test FractionPrinterParser.
OK, then I'd add some comments that the test covers `NanoPrinterParser` as well. ------------- PR: https://git.openjdk.java.net/jdk/pull/6188