ChunkedNioFile Class — netty Architecture

Source Code

handler/src/main/java/io/netty/handler/stream/ChunkedNioFile.java lines 38–181

public class ChunkedNioFile implements ChunkedInput<ByteBuf> {

    private final FileChannel in;
    private final long startOffset;
    private final long endOffset;
    private final int chunkSize;
    private long offset;

    /**
     * Creates a new instance that fetches data from the specified file.
     */
    public ChunkedNioFile(File in) throws IOException {
        this(new RandomAccessFile(in, "r").getChannel());
    }

    /**
     * Creates a new instance that fetches data from the specified file.
     *
     * @param chunkSize the number of bytes to fetch on each
     *                  {@link #readChunk(ChannelHandlerContext)} call
     */
    public ChunkedNioFile(File in, int chunkSize) throws IOException {
        this(new RandomAccessFile(in, "r").getChannel(), chunkSize);
    }

    /**
     * Creates a new instance that fetches data from the specified file.
     */
    public ChunkedNioFile(FileChannel in) throws IOException {
        this(in, ChunkedStream.DEFAULT_CHUNK_SIZE);
    }

    /**
     * Creates a new instance that fetches data from the specified file.
     *
     * @param chunkSize the number of bytes to fetch on each
     *                  {@link #readChunk(ChannelHandlerContext)} call
     */
    public ChunkedNioFile(FileChannel in, int chunkSize) throws IOException {
        this(in, 0, in.size(), chunkSize);
    }

    /**
     * Creates a new instance that fetches data from the specified file.
     *
     * @param offset the offset of the file where the transfer begins
     * @param length the number of bytes to transfer
     * @param chunkSize the number of bytes to fetch on each
     *                  {@link #readChunk(ChannelHandlerContext)} call
     */
    public ChunkedNioFile(FileChannel in, long offset, long length, int chunkSize)
            throws IOException {
        ObjectUtil.checkNotNull(in, "in");
        ObjectUtil.checkPositiveOrZero(offset, "offset");
        ObjectUtil.checkPositiveOrZero(length, "length");
        ObjectUtil.checkPositive(chunkSize, "chunkSize");
        if (!in.isOpen()) {
            throw new ClosedChannelException();
        }
        this.in = in;
        this.chunkSize = chunkSize;
        this.offset = startOffset = offset;
        endOffset = offset + length;
    }

    /**
     * Returns the offset in the file where the transfer began.
     */
    public long startOffset() {
        return startOffset;
    }

    /**
     * Returns the offset in the file where the transfer will end.
     */
    public long endOffset() {
        return endOffset;
    }

    /**
     * Returns the offset in the file where the transfer is happening currently.