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<TITLE>Persisting Changes to a Memory-Mapped ByteBuffer
(Java Developers Almanac Example)
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<h3>
e167.
Persisting Changes to a Memory-Mapped ByteBuffer</h3>
Changes to a memory-mapped <code>ByteBuffer</code> are not necessarily sent
immediately to the underlying storage device. In some applications,
such as with a memory-mapped register, the change should be sent
immediately. The <code>MappedByteBuffer.force()</code> method is used to
force all changes to the underlying storage device immediately.
<pre>
try {
// Create a ByteBuffer on a memory-mapped file
File file = new File(<font color="#0066ff"><i>"filename"</i></font>);
FileChannel channel = new RandomAccessFile(file, "rw").getChannel();
MappedByteBuffer buf = channel.map(FileChannel.MapMode.READ_WRITE, 0, (int)channel.size());
// Make a change to the ByteBuffer
<font color="#0066ff"><i>buf.put(0, (byte)0xFF);</i></font>
// Force the change to the file system
buf.force();
// Close the file
channel.close();
} catch (IOException e) {
}
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Related Examples
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e166. <a class="eglink" href="CreateMemMap.html?l=rel">
Creating a Memory-Mapped File
</a>
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e168. <a class="eglink" href="IsDirect.html?l=rel">
Determining If a ByteBuffer Is Direct
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e169. <a class="eglink" href="ReadChannel.html?l=rel">
Reading from a Channel with a ByteBuffer
</a>
<br>
e170. <a class="eglink" href="WriteChannel.html?l=rel">
Writing to a Channel with a ByteBuffer
</a>
<br>
e171. <a class="eglink" href="WriteBuffer.html?l=rel">
Writing and Appending a ByteBuffer to a File
</a>
<br>
e172. <a class="eglink" href="File2File.html?l=rel">
Copying One File to Another
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See also:
<a class="eglink" href="/egs/java.nio/pkg.html?l=rel#Byte%20Buffers">
Byte Buffers
</a>
<a class="eglink" href="/egs/java.nio/pkg.html?l=rel#File%20Locking">
File Locking
</a>
<a class="eglink" href="/egs/java.nio/pkg.html?l=rel#Sockets">
Sockets
</a>
<a class="eglink" href="/egs/java.nio/pkg.html?l=rel#Streams">
Streams
</a>
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