[FLUME-3229] CounterGroup#counters use ConcurrentHashMap instead of HashMap

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: yangkun
• Created: 11/Apr/18 13:29
• Updated: 03/May/18 04:49

Description

Currently, The CounterGroup#counters use HashMap, so this class all methods use the synchronized, if not use HashMap, change to use ConcurrentHashMap , some methods, for example: get(String)、incrementAndGet(String)、addAndGet(String, Long)、set(String, Long)、getCounter(String), etc. can remove the synchronized, because they are thread safe.This can take a little performance improvement.

// use ConcurrentHashMap instead of HashMap
private ConcurrentHashMap<String, AtomicLong> counters;

public CounterGroup()

{ counters = new ConcurrentHashMap<>(); }

// no need use synchronized
public Long get(String name)

{ return getCounter(name).get(); }

// no need use synchronized
public Long incrementAndGet(String name)

{ return getCounter(name).incrementAndGet(); }

// no need use synchronized
public AtomicLong getCounter(String name) {
if (!counters.containsKey(name))

{ // use putIfAbsent method counters.putIfAbsent(name, new AtomicLong()); }

return counters.get(name);
}

Issue Links

• links to: GitHub Pull Request #207