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import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import com.googlecode.javaewah.datastructure.BitSet;
import com.googlecode.javaewah.datastructure.ImmutableBitSet;
public class BitSetMemoryMappingExample {
public static void main(String[] args) throws IOException {
File tmpfile = File.createTempFile("javaewah", "bin");
tmpfile.deleteOnExit();
final FileOutputStream fos = new FileOutputStream(tmpfile);
BitSet Bitmap = BitSet.bitmapOf(0, 2, 55, 64, 512);
System.out.println("Created the bitmap " + Bitmap);
Bitmap.serialize(new DataOutputStream(fos));
long totalcount = fos.getChannel().position();
System.out.println("Serialized total count = " + totalcount + " bytes");
fos.close();
RandomAccessFile memoryMappedFile = new RandomAccessFile(tmpfile, "r");
ByteBuffer bb = memoryMappedFile.getChannel().map(
FileChannel.MapMode.READ_ONLY, 0, totalcount);
ImmutableBitSet mapped = new ImmutableBitSet(bb.asLongBuffer());
System.out.println("Mapped the bitmap " + mapped);
memoryMappedFile.close();
if (!mapped.equals(Bitmap))
throw new RuntimeException("Will not happen");
}
}
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