Class ContentLengthInputStream

  • All Implemented Interfaces:
    Closeable, AutoCloseable

    public class ContentLengthInputStream
    extends InputStream
    Cuts the wrapped InputStream off after a specified number of bytes.

    Implementation note: Choices abound. One approach would pass through the InputStream.mark(int) and InputStream.reset() calls to the underlying stream. That's tricky, though, because you then have to start duplicating the work of keeping track of how much a reset rewinds. Further, you have to watch out for the "readLimit", and since the semantics for the readLimit leave room for differing implementations, you might get into a lot of trouble.

    Alternatively, you could make this class extend BufferedInputStream and then use the protected members of that class to avoid duplicated effort. That solution has the side effect of adding yet another possible layer of buffering.

    Then, there is the simple choice, which this takes - simply don't support InputStream.mark(int) and InputStream.reset(). That choice has the added benefit of keeping this class very simple.

    Since:
    2.0
    Author:
    Ortwin Glueck, Eric Johnson, Mike Bowler
    • Constructor Detail

      • ContentLengthInputStream

        public ContentLengthInputStream​(InputStream in,
                                        int contentLength)
        Deprecated.
        use ContentLengthInputStream(InputStream, long) Creates a new length limited stream
        Parameters:
        in - The stream to wrap
        contentLength - The maximum number of bytes that can be read from the stream. Subsequent read operations will return -1.
      • ContentLengthInputStream

        public ContentLengthInputStream​(InputStream in,
                                        long contentLength)
        Creates a new length limited stream
        Parameters:
        in - The stream to wrap
        contentLength - The maximum number of bytes that can be read from the stream. Subsequent read operations will return -1.
        Since:
        3.0
    • Method Detail

      • close

        public void close()
                   throws IOException

        Reads until the end of the known length of content.

        Does not close the underlying socket input, but instead leaves it primed to parse the next response.

        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Overrides:
        close in class InputStream
        Throws:
        IOException - If an IO problem occurs.
      • read

        public int read​(byte[] b,
                        int off,
                        int len)
                 throws IOException
        Does standard InputStream.read(byte[], int, int) behavior, but also notifies the watcher when the contents have been consumed.
        Overrides:
        read in class InputStream
        Parameters:
        b - The byte array to fill.
        off - Start filling at this position.
        len - The number of bytes to attempt to read.
        Returns:
        The number of bytes read, or -1 if the end of content has been reached.
        Throws:
        IOException - Should an error occur on the wrapped stream.
      • read

        public int read​(byte[] b)
                 throws IOException
        Read more bytes from the stream.
        Overrides:
        read in class InputStream
        Parameters:
        b - The byte array to put the new data in.
        Returns:
        The number of bytes read into the buffer.
        Throws:
        IOException - If an IO problem occurs
        See Also:
        InputStream.read(byte[])
      • skip

        public long skip​(long n)
                  throws IOException
        Skips and discards a number of bytes from the input stream.
        Overrides:
        skip in class InputStream
        Parameters:
        n - The number of bytes to skip.
        Returns:
        The actual number of bytes skipped. <= 0 if no bytes are skipped.
        Throws:
        IOException - If an error occurs while skipping bytes.
        See Also:
        InputStream.skip(long)