Class CharStreams



  • @Beta
    public final class CharStreams
    extends Object
    Provides utility methods for working with character streams.

    All method parameters must be non-null unless documented otherwise.

    Some of the methods in this class take arguments with a generic type of Readable & Closeable. A Reader implements both of those interfaces. Similarly for Appendable & Closeable and Writer.

    Since:
    1.0
    • Method Detail

      • copy

        public static long copy(Readable from,
                                Appendable to)
                         throws IOException
        Copies all characters between the Readable and Appendable objects. Does not close or flush either object.
        Parameters:
        from - the object to read from
        to - the object to write to
        Returns:
        the number of characters copied
        Throws:
        IOException - if an I/O error occurs
      • toString

        public static String toString(Readable r)
                               throws IOException
        Reads all characters from a Readable object into a String. Does not close the Readable.
        Parameters:
        r - the object to read from
        Returns:
        a string containing all the characters
        Throws:
        IOException - if an I/O error occurs
      • readLines

        public static <T> T readLines(Readable readable,
                                      LineProcessor<T> processor)
                               throws IOException
        Streams lines from a Readable object, stopping when the processor returns false or all lines have been read and returning the result produced by the processor. Does not close readable. Note that this method may not fully consume the contents of readable if the processor stops processing early.
        Throws:
        IOException - if an I/O error occurs
        Since:
        14.0
      • skipFully

        public static void skipFully(Reader reader,
                                     long n)
                              throws IOException
        Discards n characters of data from the reader. This method will block until the full amount has been skipped. Does not close the reader.
        Parameters:
        reader - the reader to read from
        n - the number of characters to skip
        Throws:
        EOFException - if this stream reaches the end before skipping all the characters
        IOException - if an I/O error occurs
      • nullWriter

        public static Writer nullWriter()
        Returns a Writer that simply discards written chars.
        Since:
        15.0
      • asWriter

        public static Writer asWriter(Appendable target)
        Returns a Writer that sends all output to the given Appendable target. Closing the writer will close the target if it is Closeable, and flushing the writer will flush the target if it is Flushable.
        Parameters:
        target - the object to which output will be sent
        Returns:
        a new Writer object, unless target is a Writer, in which case the target is returned