Module java.base

Package java.io

Class FilterReader

java.lang.Object

java.io.Reader

java.io.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:

1.1

Field Summary

Fields

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

Fields declared in class java.io.Reader

lock

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
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.

Methods declared in class java.io.Reader

close, nullReader, read, read, transferTo

Methods declared in 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)

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

IndexOutOfBoundsException - 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

reset

public void reset()
           throws IOException

Resets the stream.

Overrides:

reset in class Reader

Throws:

IOException - If an I/O error occurs