java.io

Class FilterReader

  • All Implemented Interfaces:
    Closeable, AutoCloseable, Readable
    Direct Known Subclasses:
    PushbackReader 

    public abstract class FilterReader
extends Reader
    Abstract class for reading filtered character streams. The abstract class FilterReader itself provides default methods that pass all requests to the contained stream. Subclasses of FilterReader should override some of these methods and may also provide additional methods and fields.
    Since:
    JDK1.1

    • Field Summary

      Fields

      Modifier and Type Field and Description
      protected Reader in
      The underlying character-input stream.

    • Constructor Summary

      Constructors

      Modifier Constructor and Description
      protected FilterReader(Reader in)
      Creates a new filtered reader.

    • Method Summary

      Modifier and Type Method and 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.
      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.
      long skip(long n)
      Skips characters.

    • Field Detail

      • in

        protected Reader in
        The underlying character-input stream.

    • Constructor Detail

      • FilterReader

        protected FilterReader(Reader in)
        Creates a new filtered reader.
        Parameters:
        in - a Reader object providing the underlying stream.
        Throws:
        NullPointerException - if in is null

    • Method Detail

      • read

        public int read()
         throws IOException
        Reads a single character.
        Overrides:
        read in class  Reader
        Returns:
        The character read, as an integer in the range 0 to 65535 ( 0x00-0xffff), 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 storing 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

      • skip

        public long skip(long n)
          throws IOException
        Skips characters.
        Overrides:
        skip in class  Reader
        Parameters:
        n - 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, false otherwise. Note that returning false does not guarantee that the next read will block.
        Throws:
        IOException - If an I/O error occurs

      • markSupported

        public boolean markSupported()
        Tells whether this stream supports the mark() operation.
        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.
        Overrides:
        mark in class  Reader
        Parameters:
        readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail.
        Throws:
        IOException - If an I/O error occurs

      • close

        public void close()
           throws IOException
        Description copied from class: Reader
        Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect.
        Specified by:
        close in interface  Closeable
        Specified by:
        close in interface  AutoCloseable
        Specified by:
        close in class  Reader
        Throws:
        IOException - If an I/O error occurs