java.io
Class 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 according to a specified character encoding. 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.

For top efficiency, consider wrapping an InputStreamReader within a BufferedReader. For example:

 BufferedReader in
   = new BufferedReader(new InputStreamReader(System.in));
 
Version:
1.25, 00/02/02
Author:
Mark Reinhold
Since:
JDK1.1
See Also:
BufferedReader
InputStream
Character encodings
Constructor Detail

InputStreamReader

public InputStreamReader(InputStream in)
Create an InputStreamReader that uses the default character encoding.
Parameters:
in - An InputStream

InputStreamReader

public InputStreamReader(InputStream in,
                         String enc)
Create an InputStreamReader that uses the named character encoding.
Parameters:
in - An InputStream
enc - The name of a supported character encoding
Throws:
UnsupportedEncodingException - If the named encoding is not supported

InputStreamReader

private InputStreamReader(InputStream in,
                          ByteToCharConverter btc)
Create an InputStreamReader that uses the specified byte-to-character converter. The converter is assumed to have been reset.
Parameters:
in - An InputStream
btc - A ByteToCharConverter

Method Detail

getEncoding

public String getEncoding()
Returns the canonical name of the character encoding being used by this stream. If this InputStreamReader was created with the {@link #InputStreamReader(InputStream, String)} constructor then the returned encoding name, being canonical, may differ from the encoding name passed to the constructor. May return null if the stream has been closed.
Returns:
a String representing the encoding name, or possibly null if the stream has been closed
See Also:
Character encodings

inReady

private boolean inReady()
Tell whether the underlying byte stream is ready to be read. Return false for those streams that do not support available(), such as the Win32 console stream.

ensureOpen

private void ensureOpen()
Check to make sure that the stream has not been closed

read

public int read()
Read a single character.
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)
Read characters into a portion of an array.
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()
Tell whether this stream is ready to be read. An InputStreamReader is ready if its input buffer is not empty, or if bytes are available to be read from the underlying byte stream.
Throws:
IOException - If an I/O error occurs

close

public void close()
Close the stream.
Throws:
IOException - If an I/O error occurs