Re: RFR: 8282178: Replace simple iterations of Map.entrySet with Map.forEach calls
On Wed, 23 Feb 2022 22:33:42 GMT, liach wrote: > Replaces simple `for (Map.Entry entry : map.entrySet())` with > `map.forEach((k, v) ->)` calls. This change is better for thread-safety and > reduces allocation for some map implementations. > > A more in-depth description of benefits is available at > https://mail.openjdk.java.net/pipermail/core-libs-dev/2022-February/086201.html > and at the JBS issue itself. > > A [jmh > comparison](https://jmh.morethan.io/?sources=https://gist.githubusercontent.com/liach/0c0f79f0c0b9b78f474d65cda2c5f7b5/raw/4f2a160c51164aefdfac6ab5a19bdbc8c65f5fcf/base-results.json,https://gist.githubusercontent.com/liach/0c0f79f0c0b9b78f474d65cda2c5f7b5/raw/4f2a160c51164aefdfac6ab5a19bdbc8c65f5fcf/head-results.json) > on the performance of the existing `HashMapBench` shows that the performance > of `putAll` for `HashMap` has not significantly changed. In a short summary, on mailing list, stuart says this doesn't benefit concurrent maps; Remi proposed to deprecate the synchronized collections for the peculiarities of iteration; kevin said that this change improves code clarity. Hence, I still believe changing to foreach calls in putAll can potentially benefit adding from maps that have expensive iterators and entry wrappers. - PR: https://git.openjdk.java.net/jdk/pull/7601
Re: RFR: 8282178: Replace simple iterations of Map.entrySet with Map.forEach calls
On Wed, 23 Feb 2022 23:50:49 GMT, PROgrm_JARvis wrote:
>> Replaces simple `for (Map.Entry entry : map.entrySet())` with
>> `map.forEach((k, v) ->)` calls. This change is better for thread-safety and
>> reduces allocation for some map implementations.
>>
>> A more in-depth description of benefits is available at
>> https://mail.openjdk.java.net/pipermail/core-libs-dev/2022-February/086201.html
>> and at the JBS issue itself.
>>
>> A [jmh
>> comparison](https://jmh.morethan.io/?sources=https://gist.githubusercontent.com/liach/0c0f79f0c0b9b78f474d65cda2c5f7b5/raw/4f2a160c51164aefdfac6ab5a19bdbc8c65f5fcf/base-results.json,https://gist.githubusercontent.com/liach/0c0f79f0c0b9b78f474d65cda2c5f7b5/raw/4f2a160c51164aefdfac6ab5a19bdbc8c65f5fcf/head-results.json)
>> on the performance of the existing `HashMapBench` shows that the
>> performance of `putAll` for `HashMap` has not significantly changed.
>
> src/java.base/share/classes/java/util/AbstractMap.java line 881:
>
>> 879: * used before indy and lambda expressions are ready in initPhase1.
>> 880: * Regular code can safely use {@code map::put} instead.
>> 881: */
>
> Looks like `@param ` and `@param ` are missing although Javadoc-comment
> is used.
This javadoc-style comment is designed like the javadoc for `jdk.internal.`
packages or package-private elements in `java.` packages, which only talks
about cautions and rationale for this class. It is not rendered in the
generated API documentations and not a public API.
-
PR: https://git.openjdk.java.net/jdk/pull/7601
Re: RFR: 8282178: Replace simple iterations of Map.entrySet with Map.forEach calls
On Wed, 23 Feb 2022 22:33:42 GMT, liach wrote:
> Replaces simple `for (Map.Entry entry : map.entrySet())` with
> `map.forEach((k, v) ->)` calls. This change is better for thread-safety and
> reduces allocation for some map implementations.
>
> A more in-depth description of benefits is available at
> https://mail.openjdk.java.net/pipermail/core-libs-dev/2022-February/086201.html
> and at the JBS issue itself.
>
> A [jmh
> comparison](https://jmh.morethan.io/?sources=https://gist.githubusercontent.com/liach/0c0f79f0c0b9b78f474d65cda2c5f7b5/raw/4f2a160c51164aefdfac6ab5a19bdbc8c65f5fcf/base-results.json,https://gist.githubusercontent.com/liach/0c0f79f0c0b9b78f474d65cda2c5f7b5/raw/4f2a160c51164aefdfac6ab5a19bdbc8c65f5fcf/head-results.json)
> on the performance of the existing `HashMapBench` shows that the performance
> of `putAll` for `HashMap` has not significantly changed.
Changes requested by jarviscr...@github.com (no known OpenJDK username).
src/java.base/share/classes/java/util/AbstractMap.java line 881:
> 879: * used before indy and lambda expressions are ready in initPhase1.
> 880: * Regular code can safely use {@code map::put} instead.
> 881: */
Looks like `@param ` and `@param ` are missing although Javadoc-comment
is used.
-
PR: https://git.openjdk.java.net/jdk/pull/7601
