/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.zookeeper.server.metric;

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.zookeeper.metrics.SummarySet;

/**
 * Generic set of long counters that keep track of min/max/avg
 * for different keys.
 * The counter is thread-safe
 */
public class AvgMinMaxCounterSet extends Metric implements SummarySet {

    private final String name;

    private ConcurrentHashMap<String, AvgMinMaxCounter> counters = new ConcurrentHashMap<>();

    public AvgMinMaxCounterSet(String name) {
        this.name = name;
    }

    private AvgMinMaxCounter getCounterForKey(String key) {
        AvgMinMaxCounter counter = counters.get(key);
        if (counter == null) {
            counters.putIfAbsent(key, new AvgMinMaxCounter(key + "_" + name));
            counter = counters.get(key);
        }

        return counter;
    }

    public void addDataPoint(String key, long value) {
        getCounterForKey(key).addDataPoint(value);
    }

    public void resetMax() {
        for (Map.Entry<String, AvgMinMaxCounter> entry : counters.entrySet()) {
            entry.getValue().resetMax();
        }
    }

    public void reset() {
        for (Map.Entry<String, AvgMinMaxCounter> entry : counters.entrySet()) {
            entry.getValue().reset();
        }
    }

    @Override
    public void add(String key, long value) {
        addDataPoint(key, value);
    }

    @Override
    public Map<String, Object> values() {
        Map<String, Object> m = new LinkedHashMap<>();
        for (Map.Entry<String, AvgMinMaxCounter> entry : counters.entrySet()) {
            m.putAll(entry.getValue().values());
        }
        return m;
    }

}

@@ -1470,96 +1470,14 @@
     
-AvgMinMaxCounter counter = counters.get(key);%0A        if (counter == null) %7B%0A           
+return
  cou
@@ -1482,19 +1482,23 @@
 ounters.
+com
 put
+e
 IfAbsent
@@ -1502,16 +1502,20 @@
 ent(key,
+ k-%3E
  new Avg
@@ -1529,18 +1529,16 @@
 ounter(k
-ey
  + %22_%22 +
@@ -1550,84 +1550,8 @@
 ));%0A
-            counter = counters.get(key);%0A        %7D%0A%0A        return counter;%0A
     

Use Map computeIfAbsent in AvgMinMaxCounterSet Class