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## java.io
Class FilterReader

    java.lang.Object
      java.io.Reader
          java.io.FilterReader

All Implemented Interfaces:
  Closeable, 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
`protected Reader` | `in` The underlying character-input stream.

Fields inherited from class java.io.Reader
`lock`

Constructor Summary
`protected` | `FilterReader(Reader in)` Create a new filtered reader.

Method Summary
`void` | `close()` Close the stream.
`void` | `mark(int readAheadLimit)` Mark the present position in the stream.
`boolean` | `markSupported()` Tell whether this stream supports the mark() operation.
`int` | `read()` Read a single character.
`int` | `read(char[] cbuf, int off, int len)` Read characters into a portion of an array.
`boolean` | `ready()` Tell whether this stream is ready to be read.
`void` | `reset()` Reset the stream.
`long` | `skip(long n)` Skip characters.

Methods inherited from class java.io.Reader
`read, read`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### in

    protected Reader in

  The underlying character-input stream.

Constructor Detail

### FilterReader

    protected FilterReader(Reader in)

  Create 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

  Read 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

  Read 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

  Skip 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

  Tell 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()

  Tell 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

  Mark 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

### reset

    public void reset()
               throws IOException

  Reset the stream.

  Overrides:
    `reset` in class `Reader`
  Throws:
    `IOException` - If an I/O error occurs

### close

    public void close()
               throws IOException

  Close the stream.

  Specified by:
    `close` in interface `Closeable`
  Specified by:
    `close` in class `Reader`
  Throws:
    `IOException` - If an I/O error occurs

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.