com.opentable.metrics.graphite.MetricSets Maven / Gradle / Ivy

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/*
 * Licensed 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 com.opentable.metrics.graphite;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;

import com.codahale.metrics.Metric;
import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.MetricSet;
import com.google.common.annotations.Beta;

/**
 * Utility class for interacting with {@link MetricSet}s.
 */
@Beta
public final class MetricSets {
    private MetricSets() { }
    /**
     * Create a MetricSet view that returns the given set's metrics, with a name transformer
     * applied to each key.
     * @param set The set
     * @param nameTransformer The transforming function
     * @return MetricsSet metric Set
     */
    public static MetricSet transformNames(MetricSet set, Function nameTransformer) {
        return () -> {
            final Map innerMetrics = set.getMetrics();
            final Map result = new HashMap<>(innerMetrics.size());
            innerMetrics.forEach((k, v) -> result.put(nameTransformer.apply(k), v));
            return Collections.unmodifiableMap(result);
        };
    }

    /**
     * Create a view that is the summation of multiple {@link MetricSet}s.
     * If more than one metric set has a given key, the value is arbitrary.
     * @param sets sets to combine
     * @return MetricSet metricset
     */
    public static MetricSet combine(Iterable sets) {
        return () -> {
            final Map result = new HashMap<>();
            sets.forEach(ms -> result.putAll(ms.getMetrics()));
            return Collections.unmodifiableMap(result);
        };
    }

    /**
     * Create a view that is the summation of multiple {@link MetricSet}s.
     * If more than one metric set has a given key, the value is arbitrary.
     * @param sets a list of sets to combine
     * @return MetricSet
     */
    public static MetricSet combine(MetricSet... sets) {
        return combine(Arrays.asList(sets));
    }

    /**
     * Return new metric set view that prefixes the names of the entries.
     * @param prefix Prefix to apply to metric set
     * @param metricSet metric set to operate on
     * @return MetricSet metric set with prefix
     */
    public static MetricSet prefix(String prefix, MetricSet metricSet) {
        return transformNames(metricSet, k -> prefix + k);
    }

    /**
     * Combine multiple metric sets and prefix their names.
     * @param prefix Prefix to apply to metric sets
     * @param metricSets A set of metric sets to which the prefix is applied
     * @return MetricSet the resultant metric set
     */
    public static MetricSet combineAndPrefix(String prefix, MetricSet... metricSets) {
        return prefix(prefix, combine(metricSets));
    }

    /**
     * Remove all {@param metrics} from the given {@param metricRegistry}.
     * @param metricRegistry A Metric Registry to remove metrics from
     * @param metrics The set of metrics to remove
     */
    public static void removeAll(MetricRegistry metricRegistry, MetricSet metrics) {
        metrics.getMetrics().keySet().forEach(metricRegistry::remove);
    }
}