utils/misc/src/main/java/org/onlab/metrics/MetricsComponent.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.onlab.metrics;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 * Components to register for metrics.
 */
public class MetricsComponent implements MetricsComponentRegistry {
    private final String name;

    /**
     * Registry to hold the Features defined in this Component.
     */
    private final ConcurrentMap<String, MetricsFeature> featuresRegistry =
            new ConcurrentHashMap<>();

    /**
     * Constructs a component from a name.
     *
     * @param newName name of the component
     */
    MetricsComponent(final String newName) {
        name = newName;
    }

    @Override
    public String getName() {
        return name;
    }

    @Override
    public MetricsFeature registerFeature(final String featureName) {
        MetricsFeature feature = featuresRegistry.get(featureName);
        if (feature == null) {
            final MetricsFeature createdFeature =
                new MetricsFeature(featureName);
            feature = featuresRegistry.putIfAbsent(featureName, createdFeature);
            if (feature == null) {
                feature = createdFeature;
            }
        }
        return feature;
    }
}