google.registry.monitoring.metrics.MetricsUtils.java Source code

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Here is the source code for google.registry.monitoring.metrics.MetricsUtils.java

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// Copyright 2016 The Nomulus Authors. All Rights Reserved.
//
// 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 google.registry.monitoring.metrics;

import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.collect.ImmutableList;
import java.util.concurrent.ConcurrentHashMap;

/** Static helper methods for the Metrics library. */
final class MetricsUtils {

    private static final Double NEGATIVE_ZERO = -0.0;
    private static final String LABEL_SIZE_ERROR = "The count of labelValues must be equal to the underlying Metric's count of labels.";

    /**
     * The below constants replicate the default initial capacity, load factor, and concurrency level
     * for {@link ConcurrentHashMap} as of Java SE 7. They are recorded here so that a {@link
     * com.google.common.util.concurrent.Striped} object can be constructed with a concurrency level
     * matching the default concurrency level of a {@link ConcurrentHashMap}.
     */
    private static final int HASHMAP_INITIAL_CAPACITY = 16;
    private static final float HASHMAP_LOAD_FACTOR = 0.75f;
    static final int DEFAULT_CONCURRENCY_LEVEL = 16;

    private MetricsUtils() {
    }

    /**
     * Check that the given {@code labelValues} match in count with the count of {@link
     * LabelDescriptor} instances on the given {@code metric}
     *
     * @throws IllegalArgumentException if there is a count mismatch.
     */
    static void checkLabelValuesLength(Metric<?> metric, String[] labelValues) {
        checkArgument(labelValues.length == metric.getMetricSchema().labels().size(), LABEL_SIZE_ERROR);
    }

    /**
     * Check that the given {@code labelValues} match in count with the count of {@link
     * LabelDescriptor} instances on the given {@code metric}
     *
     * @throws IllegalArgumentException if there is a count mismatch.
     */
    static void checkLabelValuesLength(Metric<?> metric, ImmutableList<String> labelValues) {
        checkArgument(labelValues.size() == metric.getMetricSchema().labels().size(), LABEL_SIZE_ERROR);
    }

    /** Check that the given double is not infinite, {@code NaN}, or {@code -0.0}. */
    static void checkDouble(double value) {
        checkArgument(!Double.isInfinite(value) && !Double.isNaN(value) && !NEGATIVE_ZERO.equals(value),
                "value must be finite, not NaN, and not -0.0");
    }

    static <K, V> ConcurrentHashMap<K, V> newConcurrentHashMap(int concurrencyLevel) {
        return new ConcurrentHashMap<>(HASHMAP_INITIAL_CAPACITY, HASHMAP_LOAD_FACTOR, concurrencyLevel);
    }
}