Class FileInputStream

lib/java/io/FileInputStream.java:35–339

A specialized InputStream that reads from a file in the file system. All read requests made by calling methods in this class are directly forwarded to the equivalent function of the underlying operating system. Since this may induce some performance penalty, in particular if many small read

 * @see FileOutputStream
 */
public class FileInputStream extends InputStream implements Closeable {
    /**
     * The {@link FileDescriptor} representing this {@code FileInputStream}.
     */
    FileDescriptor fd;

    // The unique file channel associated with this FileInputStream (lazily
    // initialized).
//    private FileChannel channel;

    private IFileSystem fileSystem = Platform.getFileSystem();

    private static class RepositioningLock {
    }

    private Object repositioningLock = new RepositioningLock();

    /**
     * Constructs a new {@code FileInputStream} based on {@code file}.
     * 
     * @param file
     *            the file from which this stream reads.
     * @throws FileNotFoundException
     *             if {@code file} does not exist.
     * @throws SecurityException
     *             if a {@code SecurityManager} is installed and it denies the
     *             read request.
     */
    public FileInputStream(File file) throws FileNotFoundException {
        super();
//        SecurityManager security = System.getSecurityManager();
//        if (security != null) {
//            // For compatibility, nulls are passed to the manager.
//            String filePath = (null == file ? null : file.getPath());
//            security.checkRead(filePath);
//        }
        if (file == null) {
            // luni.4D=Argument must not be null
            throw new NullPointerException(Messages.getString("luni.4D")); //$NON-NLS-1$
        }
        fd = new FileDescriptor();
        fd.readOnly = true;
        fd.descriptor = fileSystem.open(file.properPath(true),
                IFileSystem.O_RDONLY);
//        channel = FileChannelFactory.getFileChannel(this, fd.descriptor,
//                IFileSystem.O_RDONLY);
    }

    /**
     * Constructs a new {@code FileInputStream} on the {@link FileDescriptor}
     * {@code fd}. The file must already be open, therefore no
     * {@code FileNotFoundException} will be thrown.
     * 
     * @param fd
     *            the FileDescriptor from which this stream reads.
     * @throws NullPointerException
     *             if {@code fd} is {@code null}.
     * @throws SecurityException