[PATCH] 8247402: Rewrite the implementation requirements for Map::compute()

[林自均]

Hi Martin,

I see your point. Thank you for demostrating this for me.

Here's my updated patch:

# HG changeset patch
# User John Lin <johnlinp at gmail.com>
# Date 1591923561 -28800
#      Fri Jun 12 08:59:21 2020 +0800
# Node ID e01d9d020506a88d3d585bd3264594a26450c659
# Parent  49a68abdb0ba68351db0f140ddac793b1c391bd5
8247402: Rewrite the implementation requirements for Map::compute()

diff --git a/src/java.base/share/classes/java/util/Map.java
b/src/java.base/share/classes/java/util/Map.java
--- a/src/java.base/share/classes/java/util/Map.java
+++ b/src/java.base/share/classes/java/util/Map.java
@@ -1113,17 +1113,12 @@ public interface Map<K, V> {
      * <pre> {@code
      * V oldValue = map.get(key);
      * V newValue = remappingFunction.apply(key, oldValue);
-     * if (oldValue != null) {
-     *    if (newValue != null)
-     *       map.put(key, newValue);
-     *    else
-     *       map.remove(key);
+     * if (newValue != null) {
+     *     map.put(key, newValue);
      * } else {
-     *    if (newValue != null)
-     *       map.put(key, newValue);
-     *    else
-     *       return null;
+     *     map.remove(key);
      * }
+     * return newValue;
      * }</pre>
      *
      * <p>The default implementation makes no guarantees about detecting if the

By the way, I saw everyone in this mailing list is using webrev.
However, the tutorial https://openjdk.java.net/guide/codeReview.html
says that only the users with push access to the OpenJDK Mercurial
server can use webrev. Can I apply for push access to the OpenJDK
Mercurial server too?

Best,
John Lin

Martin Buchholz <martinrb at google.com> 於 2020年6月13日 週六 上午12:36寫道：
>
> If I rub that program, I get:
>
> HashMap false
> HashMap1 false
> HashMap2 true
>
> which suggests that HashMap2's implementation is wrong.