com.azure.cosmos.implementation.guava25.hash.LongAddables Maven / Gradle / Ivy

/*
 * Copyright (C) 2008 The Guava Authors
 *
 * 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.
 */

/*
 * Portions Copyright (c) Microsoft Corporation
 */

package com.azure.cosmos.implementation.guava25.hash;

import com.azure.cosmos.implementation.guava25.base.Supplier;

import java.util.concurrent.atomic.AtomicLong;

/**
 * Source of {@link LongAddable} objects that deals with GWT, Unsafe, and all that.
 *
 * @author Louis Wasserman
 */
final class LongAddables {
    private static final Supplier SUPPLIER;

    static {
        Supplier supplier;
        try {
            new LongAdder(); // trigger static initialization of the LongAdder class, which may fail
            supplier =
                new Supplier() {
                    @Override
                    public LongAddable get() {
                        return new LongAdder();
                    }
                };
        } catch (Throwable t) { // we really want to catch *everything*
            supplier =
                new Supplier() {
                    @Override
                    public LongAddable get() {
                        return new PureJavaLongAddable();
                    }
                };
        }
        SUPPLIER = supplier;
    }

    public static LongAddable create() {
        return SUPPLIER.get();
    }

    private static final class PureJavaLongAddable extends AtomicLong implements LongAddable {
        @Override
        public void increment() {
            getAndIncrement();
        }

        @Override
        public void add(long x) {
            getAndAdd(x);
        }

        @Override
        public long sum() {
            return get();
        }
    }
}