java.io
Class FilterReader

java.lang.Object
  |
  +--java.io.Reader
        |
        +--java.io.FilterReader
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, or null if the stream has been closed.
 
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
 
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, or null if the stream has been closed.

 

Constructor Detail

 

 

FilterReader

protected FilterReader(Reader in)
Create a new filtered reader.

Parameters:
in - a Reader object providing the underlying stream.

 

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 class Reader
Throws:
IOException - If an I/O error occurs