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java.io
Class InputStreamReader

java.lang.Object
 |
 +--java.io.Reader
 |
 +--java.io.InputStreamReader

Direct Known Subclasses:

FileReader

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public class InputStreamReader

extends Reader

Safe: An InputStreamReader is a bridge from byte streams to character streams: It reads bytes and decodes them into characters using a specified charset. The charset that it uses may be specified by name or may be given explicitly, or the platform's default charset 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));
 

Since:

JDK1.1

Version:

1.42, 01/12/03

Author:

Mark Reinhold

See Also:

BufferedReader, InputStream, java.nio.charset.Charset

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sd

private final sun.nio.cs.StreamDecoder sd

InputStreamReader

public InputStreamReader(InputStream in)

Enabled: Create an InputStreamReader that uses the default charset.

Parameters:

in - An InputStream

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InputStreamReader

public InputStreamReader(InputStream in,
 String charsetName)
 throws UnsupportedEncodingException

Suppressed: Create an InputStreamReader that uses the named charset.

Parameters:

in - An InputStream

charsetName - The name of a supported charset

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InputStreamReader

public InputStreamReader(InputStream in,
 java.nio.charset.Charset cs)

Suppressed: Create an InputStreamReader that uses the given charset.

Parameters:

in - An InputStream

cs - A charset

Since:

1.4

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InputStreamReader

public InputStreamReader(InputStream in,
 java.nio.charset.CharsetDecoder dec)

Suppressed: Create an InputStreamReader that uses the given charset decoder.

Parameters:

in - An InputStream

dec - A charset decoder

Since:

1.4

getEncoding

public String getEncoding()

Enabled: Return the name of the character encoding being used by this stream.

If the encoding has an historical name then that name is returned; otherwise the encoding's canonical name is returned.

If this instance was created with the InputStreamReader(InputStream, String) constructor then the returned name, being unique for the encoding, may differ from the name passed to the constructor. This method may return null if the stream has been closed.

Returns:

The historical name of this encoding, or possibly null if the stream has been closed

See Also:

java.nio.charset.Charset

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read

public int read()
 throws IOException

Enabled: Read a single character.

Overrides:

read in class Reader

Returns:

The character read, or -1 if the end of the stream has been reached

IOException

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read

public int read(char[] cbuf,
 int offset,
 int length)
 throws IOException

Enabled: Read characters into a portion of an array.

Specified by:

read in class Reader

Parameters:

cbuf - Destination buffer

offset - Offset at which to start storing characters

length - Maximum number of characters to read

Returns:

The number of characters read, or -1 if the end of the stream has been reached

IOException

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ready

public boolean ready()
 throws IOException

Enabled: 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.

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.

IOException

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close

public void close()
 throws IOException

Enabled: Close the stream.

Specified by:

close in class Reader

IOException

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