Module java.base
Package java.io

Class StringReader

    • Field Summary

    • Constructor Summary

      Constructors 
      Constructor Description
      StringReader​(String s)
      Creates a new string reader.

    • Method Summary

      Modifier and Type Method Description
      void close()
      Closes the stream and releases any system resources associated with it.
      void mark​(int readAheadLimit)
      Marks the present position in the stream.
      boolean markSupported()
      Tells whether this stream supports the mark() operation, which it does.
      int read()
      Reads a single character.
      int read​(char[] cbuf, int off, int len)
      Reads characters into a portion of an array.
      boolean ready()
      Tells whether this stream is ready to be read.
      void reset()
      Resets the stream to the most recent mark, or to the beginning of the string if it has never been marked.
      long skip​(long ns)
      Skips the specified number of characters in the stream.

    • Constructor Detail

      • StringReader

        public StringReader​(String s)
        Creates a new string reader.
        Parameters:
        s - String providing the character stream.

    • Method Detail

      • read

        public int read()
         throws IOException
        Reads a single character.
        Overrides:
        read in class Reader
        Returns:
        The character read, or -1 if the end of the stream has been reached
        Throws:
        IOException - If an I/O error occurs

      • read

        public int read​(char[] cbuf,
                int off,
                int len)
         throws IOException
        Reads characters into a portion of an array.
        Specified by:
        read in class Reader
        Parameters:
        cbuf - Destination buffer
        off - Offset at which to start writing characters
        len - Maximum number of characters to read
        Returns:
        The number of characters read, or -1 if the end of the stream has been reached
        Throws:
        IOException - If an I/O error occurs
        IndexOutOfBoundsException - If an I/O error occurs

      • skip

        public long skip​(long ns)
          throws IOException
        Skips the specified number of characters in the stream. Returns the number of characters that were skipped.

        The ns parameter may be negative, even though the skip method of the Reader superclass throws an exception in this case. Negative values of ns cause the stream to skip backwards. Negative return values indicate a skip backwards. It is not possible to skip backwards past the beginning of the string.

        If the entire string has been read or skipped, then this method has no effect and always returns 0.

        Overrides:
        skip in class Reader
        Parameters:
        ns - The number of characters to skip
        Returns:
        The number of characters actually skipped
        Throws:
        IOException - If an I/O error occurs

      • ready

        public boolean ready()
              throws IOException
        Tells whether this stream is ready to be read.
        Overrides:
        ready in class Reader
        Returns:
        True if the next read() is guaranteed not to block for input
        Throws:
        IOException - If the stream is closed

      • markSupported

        public boolean markSupported()
        Tells whether this stream supports the mark() operation, which it does.
        Overrides:
        markSupported in class Reader
        Returns:
        true if and only if this stream supports the mark operation.

      • mark

        public void mark​(int readAheadLimit)
          throws IOException
        Marks the present position in the stream. Subsequent calls to reset() will reposition the stream to this point.
        Overrides:
        mark in class Reader
        Parameters:
        readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. Because the stream's input comes from a string, there is no actual limit, so this argument must not be negative, but is otherwise ignored.
        Throws:
        IllegalArgumentException - If readAheadLimit < 0
        IOException - If an I/O error occurs

      • reset

        public void reset()
           throws IOException
        Resets the stream to the most recent mark, or to the beginning of the string if it has never been marked.
        Overrides:
        reset in class Reader
        Throws:
        IOException - If an I/O error occurs

      • close

        public void close()
        Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), or reset() invocations will throw an IOException. Closing a previously closed stream has no effect. This method will block while there is another thread blocking on the reader.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Specified by:
        close in class Reader