Package com.jalios.io

Class LineDelimiterFilterInputStream

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable
    public class LineDelimiterFilterInputStream
extends java.io.FilterInputStream
    This class is an input stream filter that provides the added functionality of converting all types of line delimiter into unix line delimiter '\n'.

    A line is a sequence of bytes ending with a carriage return character ('\r'), a newline character ('\n'), or a carriage return character followed immediately by a linefeed character. In all three cases, the line terminating character(s) are returned as a single newline character.

    Since:
    jcms-5.7.4

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.lang.String REVISION  

      • Fields inherited from class java.io.FilterInputStream

        in

    • Constructor Summary

      Constructors 
      Constructor Description
      LineDelimiterFilterInputStream​(java.io.InputStream in)
      Constructs a newline number input stream that reads its input from the specified input stream.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int available()
      Returns the number of bytes that can be read from this input stream without blocking.
      void mark​(int readlimit)
      Marks the current position in this input stream.
      int read()
      Reads the next byte of data from this input stream.
      int read​(byte[] b, int off, int len)
      Reads up to len bytes of data from this input stream into an array of bytes.
      void reset()
      Repositions this stream to the position at the time the mark method was last called on this input stream.
      long skip​(long n)
      Skips over and discards n bytes of data from this input stream.

      • Methods inherited from class java.io.FilterInputStream

        close, markSupported, read

      • Methods inherited from class java.io.InputStream

        nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • LineDelimiterFilterInputStream

        public LineDelimiterFilterInputStream​(java.io.InputStream in)
        Constructs a newline number input stream that reads its input from the specified input stream.
        Parameters:
        in - the underlying input stream.

    • Method Detail

      • read

        public int read()
         throws java.io.IOException
        Reads the next byte of data from this input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

        The read method of LineDelimiterFilterInputStream calls the read method of the underlying input stream. It checks for carriage returns and newline characters in the input, a carriage-return character or a carriage return followed by a newline character are both converted into a single newline character.

        Overrides:
        read in class java.io.FilterInputStream
        Returns:
        the next byte of data, or -1 if the end of this stream is reached.
        Throws:
        java.io.IOException - if an I/O error occurs.

      • read

        public int read​(byte[] b,
                int off,
                int len)
         throws java.io.IOException
        Reads up to len bytes of data from this input stream into an array of bytes. This method blocks until some input is available.

        The read method of LineDelimiterFilterInputStream repeatedly calls the read method of zero arguments to fill in the byte array.

        Overrides:
        read in class java.io.FilterInputStream
        Parameters:
        b - the buffer into which the data is read.
        off - the start offset of the data.
        len - the maximum number of bytes read.
        Returns:
        the total number of bytes read into the buffer, or -1 if there is no more data because the end of this stream has been reached.
        Throws:
        java.io.IOException - if an I/O error occurs.
        See Also:
        read()

      • skip

        public long skip​(long n)
          throws java.io.IOException
        Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped.

        The skip method of LineDelimiterFilterInputStream creates a byte array and then repeatedly reads into it until n bytes have been read or the end of the stream has been reached.

        Overrides:
        skip in class java.io.FilterInputStream
        Parameters:
        n - the number of bytes to be skipped.
        Returns:
        the actual number of bytes skipped.
        Throws:
        java.io.IOException - if an I/O error occurs.

      • available

        public int available()
              throws java.io.IOException
        Returns the number of bytes that can be read from this input stream without blocking.

        Note that if the underlying input stream is able to supply k input characters without blocking, the LineDelimiterFilterInputStream can guarantee only to provide k/2 characters without blocking, because the k characters from the underlying input stream might consist of k/2 pairs of '\r' and '\n', which are converted to just k/2 '\n' characters.

        Overrides:
        available in class java.io.FilterInputStream
        Returns:
        the number of bytes that can be read from this input stream without blocking.
        Throws:
        java.io.IOException - if an I/O error occurs.

      • mark

        public void mark​(int readlimit)
        Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.

        The mark method of LineDelimiterFilterInputStream remembers the current line in a private variable, and then calls the mark method of the underlying input stream.

        Overrides:
        mark in class java.io.FilterInputStream
        Parameters:
        readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.
        See Also:
        reset()

      • reset

        public void reset()
           throws java.io.IOException
        Repositions this stream to the position at the time the mark method was last called on this input stream.

        The reset method of LineDelimiterFilterInputStream resets the current line to be the line at the time the mark method was called, and then calls the reset method of the underlying input stream.

        Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parser, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails, which, if it happens within readlimit bytes, allows the outer code to reset the stream and try another parser.

        Overrides:
        reset in class java.io.FilterInputStream
        Throws:
        java.io.IOException - if an I/O error occurs.
        See Also:
        mark(int)