Example usage for java.nio.channels AsynchronousFileChannel lock

Introduction

In this page you can find the example usage for java.nio.channels AsynchronousFileChannel lock.

Prototype

public final <A> void lock(A attachment, CompletionHandler<FileLock, ? super A> handler) 

Source Link

Document

Acquires an exclusive lock on this channel's file.

Usage

From source file:ubicrypt.core.Utils.java

public static Observable<Long> write(final Path fullPath, final InputStream inputStream) {
    return Observable.create(subscriber -> {
        try {/*  www  . ja  va2  s  .  c o m*/
            final AtomicLong offset = new AtomicLong(0);
            final AsynchronousFileChannel afc = AsynchronousFileChannel.open(fullPath, StandardOpenOption.WRITE,
                    StandardOpenOption.CREATE);
            afc.lock(new Object(), new CompletionHandler<FileLock, Object>() {
                @Override
                public void completed(final FileLock lock, final Object attachment) {
                    //acquired lock
                    final byte[] buf = new byte[1 << 16];
                    try {
                        final int len = inputStream.read(buf);
                        if (len == -1) {
                            unsubscribe(subscriber, inputStream, lock);
                            return;
                        }
                        afc.write(ByteBuffer.wrap(Arrays.copyOfRange(buf, 0, len)), offset.get(), null,
                                new CompletionHandler<Integer, Object>() {
                                    @Override
                                    public void completed(final Integer result, final Object attachment) {
                                        //written chunk of bytes
                                        subscriber.onNext(offset.addAndGet(result));
                                        final byte[] buf = new byte[1 << 16];
                                        int len;
                                        try {
                                            len = inputStream.read(buf);
                                            if (len == -1) {
                                                unsubscribe(subscriber, inputStream, lock);
                                                log.debug("written:{}", fullPath);
                                                return;
                                            }
                                        } catch (final IOException e) {
                                            subscriber.onError(e);
                                            return;
                                        }
                                        if (len == -1) {
                                            unsubscribe(subscriber, inputStream, lock);
                                            log.debug("written:{}", fullPath);
                                            return;
                                        }
                                        afc.write(ByteBuffer.wrap(Arrays.copyOfRange(buf, 0, len)),
                                                offset.get(), null, this);
                                    }

                                    @Override
                                    public void failed(final Throwable exc, final Object attachment) {
                                        subscriber.onError(exc);
                                    }
                                });
                    } catch (final Exception e) {
                        close(inputStream, lock);
                        subscriber.onError(e);
                    }
                }

                @Override
                public void failed(final Throwable exc, final Object attachment) {
                    log.error("error on getting lock for:{}, error:{}", fullPath, exc.getMessage());
                    try {
                        inputStream.close();
                    } catch (final IOException e) {
                    }
                    subscriber.onError(exc);
                }
            });

        } catch (final Exception e) {
            log.error("error on file:{}", fullPath);
            subscriber.onError(e);
        }
    });
}

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