[ZOOKEEPER-4000] use the computeIfAbsent to simplify the Leader#processSync method

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.7.0
• Component/s: server
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: Ling Mao
• Created: 13/Nov/20 01:51
• Updated: 28/Mar/21 08:54
• Resolved: 17/Nov/20 17:38

Description

Look at the Leader#processSync method:

public synchronized void processSync(LearnerSyncRequest r) {
    if (outstandingProposals.isEmpty()) {
        sendSync(r);
    } else {
        List<LearnerSyncRequest> l = pendingSyncs.get(lastProposed);
        if (l == null) {
            l = new ArrayList<LearnerSyncRequest>();
        }
        l.add(r);
        pendingSyncs.put(lastProposed, l);
    }
}

we can use the computeIfAbsent to make the code more clean and elegant. For example(just one line code):

pendingSyncs.computeIfAbsent(lastProposed, k -> new ArrayList<>()).add(r);

Issue Links

• links to: GitHub Pull Request #1538