java.io
Class InputStreamReader

java.lang.Object
  java.io.Reader
      java.io.InputStreamReader

public class InputStreamReader
extends Reader

An InputStreamReader is a bridge from byte streams to character streams: It reads bytes and translates them into characters. The encoding that it uses may be specified by name, or the platform's default encoding may be accepted.

Each invocation of one of an InputStreamReader's read() methods may cause one or more bytes to be read from the underlying byte input stream. To enable the efficient conversion of bytes to characters, more bytes may be read ahead from the underlying stream than are necessary to satisfy the current read operation.

Since:

CLDC 1.0

Version:

12/17/01 (CLDC 1.1)

Author:

Nik Shaylor, Antero Taivalsaari

See Also:

Reader, UnsupportedEncodingException

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

InputStreamReader(InputStream is)
Create an InputStreamReader that uses the default character encoding.

InputStreamReader(InputStream is, String enc)
Create an InputStreamReader that uses the named character encoding.

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

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

Constructor Detail

InputStreamReader

public InputStreamReader(InputStream is)

Create an InputStreamReader that uses the default character encoding.

Parameters:

is - An InputStream

InputStreamReader

public InputStreamReader(InputStream is,
                         String enc)
                  throws UnsupportedEncodingException

Create an InputStreamReader that uses the named character encoding.

Parameters:

is - An InputStream

enc - The name of a supported character encoding

Throws:

UnsupportedEncodingException - If the named encoding is not supported

Method Detail

close

public void close()
           throws IOException

Close the stream. Closing a previously closed stream has no effect.

Specified by:

close in class Reader

Throws:

IOException - If an I/O error occurs

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 the stream does not support mark(), or if some other 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.

read

public int read()
         throws IOException

Read a single character.

Overrides:

read in class Reader

Returns:

The character read, 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

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

reset

public void reset()
           throws IOException

Reset the stream.

Overrides:

reset in class Reader

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:

IllegalArgumentException - If n is negative.

IOException - If an I/O error occurs