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:

1.1

• Field Summary

  Fields

  The underlying character-input stream.

• Constructor Summary

  Constructors

  protected

  Creates a new filtered reader.

• Method Summary

  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

  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()

  long

  skip(long n)

  Methods declared in class java.lang.Object

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

• Field Details

  • in

    The underlying character-input stream.

• Constructor Details

  • 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 Details

  • read

    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. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

    If len is zero, then no characters are read and 0 is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value -1 is returned; otherwise, at least one character is read and stored into cbuf.

    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:

    IndexOutOfBoundsException - If off is negative, or len is negative, or len is greater than cbuf.length - off

    IOException - If an I/O error occurs

  • skip

    Skips characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached. If the stream is already at its end before this method is invoked, then no characters are skipped and zero is returned.

    Overrides:

    skip in class Reader

    Parameters:

    n - The number of characters to skip

    Returns:

    The number of characters actually skipped

    Throws:

    IllegalArgumentException - If n is negative and the contained Reader's skip method throws an IllegalArgumentException for a negative parameter

    IOException - If an I/O error occurs

  • ready

    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

  • reset

    Resets the stream.

    Overrides:

    reset in class Reader

    Throws:

    IOException - If an I/O error occurs

  • close

    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 AutoCloseable

    Specified by:

    close in interface Closeable

    Specified by:

    close in class Reader

    Throws:

    IOException - If an I/O error occurs