package org.cinchapi.concourse.server.io;

import java.lang.reflect.Method;
import java.nio.MappedByteBuffer;

/**
 * An abstraction for the reflection hack that allows us to use internal JVM
 * cleaners to free memory "directly".
 * 
 * @author jnelson
 */
public final class Cleaners {

    /**
     * Force clean the {@code buffer} and unmap it from memory, if possible.
     * This method is not guaranteed to work and can cause bad things to
     * happen, so use with caution.
     * <p>
     * Inspired by <a href="http://stackoverflow.com/a/19447758/1336833">
     * http://stackoverflow.com/a/19447758/1336833</a>}
     * </p>
     * 
     * @param buffer
     */
    public static void freeMappedByteBuffer(MappedByteBuffer buffer) {
        if(supported) {
            try {
                sunMiscCleanerCleanMethod
                        .invoke(directByteBufferGetCleanerMethod.invoke(buffer));
            }
            catch (Exception e) {}
        }
    }

    // Reflection goodness
    private static Method sunMiscCleanerCleanMethod;
    private static Method directByteBufferGetCleanerMethod;
    private static boolean supported;
    static {
        try {
            directByteBufferGetCleanerMethod = Class.forName(
                    "java.nio.DirectByteBuffer").getMethod("cleaner");
            directByteBufferGetCleanerMethod.setAccessible(true);
            sunMiscCleanerCleanMethod = Class.forName("sun.misc.Cleaner")
                    .getMethod("clean");
            sunMiscCleanerCleanMethod.setAccessible(true);
            supported = true;
        }
        catch (Exception e) {
            supported = false;
        }
    }

    private Cleaners() {/* noop */}
}
@@ -1,8 +1,1191 @@
+/*%0A * The MIT License (MIT)%0A * %0A * Copyright (c) 2013-2014 Jeff Nelson, Cinchapi Software Collective%0A * %0A * Permission is hereby granted, free of charge, to any person obtaining a copy%0A * of this software and associated documentation files (the %22Software%22), to deal%0A * in the Software without restriction, including without limitation the rights%0A * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell%0A * copies of the Software, and to permit persons to whom the Software is%0A * furnished to do so, subject to the following conditions:%0A * %0A * The above copyright notice and this permission notice shall be included in%0A * all copies or substantial portions of the Software.%0A * %0A * THE SOFTWARE IS PROVIDED %22AS IS%22, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR%0A * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,%0A * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE%0A * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER%0A * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,%0A * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN%0A * THE SOFTWARE.%0A */%0A
 package 

add copyright