AllocatedNativeObject.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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package sun.nio.ch;     // Formerly in sun.misc

/**
 * ## In the fullness of time, this class will be eliminated
 */
// 代表一块本地内存（含有释放内存的操作）
class AllocatedNativeObject extends NativeObject {
    
    /**
     * Allocates a memory area of at least {@code size} bytes outside of the
     * Java heap and creates a native object for that area.
     *
     * @param size        Number of bytes to allocate
     * @param pageAligned If {@code true} then the area will be aligned on a hardware
     *                    page boundary
     *
     * @throws OutOfMemoryError If the request cannot be satisfied
     */
    AllocatedNativeObject(int size, boolean pageAligned) {
        super(size, pageAligned);
    }
    
    /**
     * Frees the native memory area associated with this object.
     */
    // 释放当前内存块（需要知道当前内存块的真实起始地址allocationAddress）
    synchronized void free() {
        if(allocationAddress != 0) {
            unsafe.freeMemory(allocationAddress);
            allocationAddress = 0;
        }
    }
    
}