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nschlimm/gist:2506857

Created April 27, 2012 07:22
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Revisions

  1. nschlimm created this gist Apr 27, 2012.
    54 changes: 54 additions & 0 deletions gistfile1.java
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,54 @@
    public class ReadWriteAll {

    public static void main(String[] args) throws InterruptedException, IOException {
    try (AsynchronousFileChannel outputfile = AsynchronousFileChannel.open(Paths.get("E:/temp/afile.out"),
    StandardOpenOption.READ, StandardOpenOption.WRITE, StandardOpenOption.CREATE,
    StandardOpenOption.DELETE_ON_CLOSE)) {
    writeFully(outputfile, (ByteBuffer) ByteBuffer.allocateDirect(1048576).put(new byte[1048576]).flip(), 0L);
    readAll(outputfile, (ByteBuffer) ByteBuffer.allocateDirect(1000).put(new byte[1000]).flip(), 1000L);
    } catch (Exception e) {
    e.printStackTrace();
    }
    }

    static void readAll(final AsynchronousFileChannel ch, final ByteBuffer dst, long filePosition)
    throws InterruptedException {
    final CountDownLatch latch = new CountDownLatch(1);

    ch.read(dst, filePosition, filePosition, new CompletionHandler<Integer, Long>() {
    public void completed(Integer bytesTransferred, Long filePosition) {
    if (bytesTransferred > 0) {
    long p = filePosition + bytesTransferred;
    ch.read(dst, p, p, this);
    } else {
    latch.countDown();
    }
    }

    public void failed(Throwable exc, Long position) {
    }
    });

    latch.await();
    }

    static void writeFully(final AsynchronousFileChannel ch, final ByteBuffer src, long filePosition)
    throws InterruptedException {
    final CountDownLatch latch = new CountDownLatch(1);
    ch.write(src, filePosition, filePosition, new CompletionHandler<Integer, Long>() {
    public void completed(Integer bytesTransferred, Long filePosition) {
    if (src.hasRemaining()) {
    long newFilePosition = filePosition + bytesTransferred;
    ch.write(src, newFilePosition, newFilePosition, this);
    } else {
    latch.countDown();
    }
    }

    public void failed(Throwable exc, Long position) {
    }
    });
    latch.await();
    }

    }