MultiReducedMetric.java

/**
 * 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.storm.metric.api;

import java.util.HashMap;
import java.util.Map;

public class MultiReducedMetric implements IMetric {
    final Map<String, ReducedMetric> value = new HashMap<>();
    final IReducer reducer;

    public MultiReducedMetric(IReducer reducer) {
        this.reducer = reducer;
    }

    public ReducedMetric scope(String key) {
        synchronized (value) {
            ReducedMetric val = value.get(key);
            if (val == null) {
                value.put(key, val = new ReducedMetric(reducer));
            }
            return val;
        }
    }

    @Override
    public Map<String, Object> getValueAndReset() {
        Map<String, Object> ret = new HashMap<>();
        synchronized (value) {
            for (Map.Entry<String, ReducedMetric> e : value.entrySet()) {
                Object val = e.getValue().getValueAndReset();
                if (val != null) {
                    ret.put(e.getKey(), val);
                }
            }
        }
        return ret;
    }
}