[ZOOKEEPER-4032] Use `Map.computeIfAbsent` instead of `if Map.get is null then put value`

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: server
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: LiAoNan
• Created: 22/Dec/20 08:50
• Updated: 23/Dec/20 00:52

Description

In this method

WatchManager.addWatch(String path, Watcher watcher, WatcherMode watcherMode)

use

Map.computeIfAbsent

simplify code like

        Set<String> paths = watch2Paths.get(watcher);
        if (paths == null) {
            paths = new HashSet<>();
            watch2Paths.put(watcher, paths);
        }

result:

Set<String> paths = watch2Paths.computeIfAbsent(watcher, k -> new HashSet<>());

Issue Links

• links to: GitHub Pull Request #1561