modules/core/src/main/java/org/apache/ignite/internal/util/GridUnsafe.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.ignite.internal.util;

import sun.misc.*;

import java.lang.reflect.*;
import java.security.*;

/**
 * Provides handle on Unsafe class from SUN which cannot be instantiated directly.
 */
public class GridUnsafe {
    /**
     * Ensure singleton.
     */
    private GridUnsafe() {
        // No-op.
    }

    /**
     * @return Instance of Unsafe class.
     */
    public static Unsafe unsafe() {
        try {
            return Unsafe.getUnsafe();
        }
        catch (SecurityException ignored) {
            try {
                return AccessController.doPrivileged
                    (new PrivilegedExceptionAction<Unsafe>() {
                        @Override public Unsafe run() throws Exception {
                            Field f = Unsafe.class.getDeclaredField("theUnsafe");

                            f.setAccessible(true);

                            return (Unsafe)f.get(null);
                        }
                    });
            }
            catch (PrivilegedActionException e) {
                throw new RuntimeException("Could not initialize intrinsics.", e.getCause());
            }
        }
    }
}