org.fife.io

Class UnicodeReader

java.lang.Object

java.io.Reader

org.fife.io.UnicodeReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

public class UnicodeReader
extends Reader

A reader capable of identifying Unicode streams by their BOMs. This class will recognize the following encodings:

• UTF-8
• UTF-16LE
• UTF-16BE
• UTF-32LE
• UTF-32BE

If the stream is not found to be any of the above, then a default encoding is used for reading. The user can specify this default encoding, or a system default will be used.

For optimum performance, it is recommended that you wrap all instances of UnicodeReader with a java.io.BufferedReader.

This class is mostly ripped off from the workaround in the description of Java Bug 4508058.

Version:

0.9

Author:

Robert Futrell

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor and Description
UnicodeReader(File file) This utility constructor is here because you will usually use a UnicodeReader on files.
UnicodeReader(File file, String defaultEncoding) This utility constructor is here because you will usually use a UnicodeReader on files.
UnicodeReader(InputStream in) Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a system default encoding is used.
UnicodeReader(InputStream in, String defaultEncoding) Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then defaultEncoding is used.
UnicodeReader(String file) This utility constructor is here because you will usually use a UnicodeReader on files.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes this reader.
String	getEncoding() Returns the encoding being used to read this input stream (i.e., the encoding of the file).
protected void	init(InputStream in, String defaultEncoding) Read-ahead four bytes and check for BOM marks.
int	read(char[] cbuf, int off, int len) Read characters into a portion of an array.

Methods inherited from class java.io.Reader

mark, markSupported, read, read, read, ready, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

UnicodeReader

public UnicodeReader(String file)
              throws IOException,
                     FileNotFoundException,
                     SecurityException

This utility constructor is here because you will usually use a UnicodeReader on files.

Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a system default encoding is used.

Parameters:

file - The file from which you want to read.

Throws:

IOException - If an error occurs when checking for/reading the BOM.

FileNotFoundException - If the file does not exist, is a directory, or cannot be opened for reading.

SecurityException - If a security manager exists and its checkRead method denies read access to the file.

UnicodeReader

public UnicodeReader(File file)
              throws IOException,
                     FileNotFoundException,
                     SecurityException

This utility constructor is here because you will usually use a UnicodeReader on files.

Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a system default encoding is used.

Parameters:

file - The file from which you want to read.

Throws:

IOException - If an error occurs when checking for/reading the BOM.

FileNotFoundException - If the file does not exist, is a directory, or cannot be opened for reading.

SecurityException - If a security manager exists and its checkRead method denies read access to the file.

UnicodeReader

public UnicodeReader(File file,
             String defaultEncoding)
              throws IOException,
                     FileNotFoundException,
                     SecurityException

This utility constructor is here because you will usually use a UnicodeReader on files.

Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a specified default encoding is used.

Parameters:

file - The file from which you want to read.

defaultEncoding - The encoding to use if no BOM is found. If this value is null, a system default is used.

Throws:

IOException - If an error occurs when checking for/reading the BOM.

FileNotFoundException - If the file does not exist, is a directory, or cannot be opened for reading.

SecurityException - If a security manager exists and its checkRead method denies read access to the file.

UnicodeReader

public UnicodeReader(InputStream in)
              throws IOException

Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then a system default encoding is used.

Parameters:

in - The input stream from which to read.

Throws:

IOException - If an error occurs when checking for/reading the BOM.

UnicodeReader

public UnicodeReader(InputStream in,
             String defaultEncoding)
              throws IOException

Creates a reader using the encoding specified by the BOM in the file; if there is no recognized BOM, then defaultEncoding is used.

Parameters:

in - The input stream from which to read.

defaultEncoding - The encoding to use if no recognized BOM is found. If this value is null, a system default is used.

Throws:

IOException - If an error occurs when checking for/reading the BOM.

Method Detail

close

public void close()
           throws IOException

Closes this reader.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class Reader

Throws:

IOException

getEncoding

public String getEncoding()

Returns the encoding being used to read this input stream (i.e., the encoding of the file). If a BOM was recognized, then the specific Unicode type is returned; otherwise, either the default encoding passed into the constructor or the system default is returned.

Returns:

The encoding of the stream.

init

protected void init(InputStream in,
        String defaultEncoding)
             throws IOException

Read-ahead four bytes and check for BOM marks. Extra bytes are unread back to the stream, only BOM bytes are skipped.

Parameters:

defaultEncoding - The encoding to use if no BOM was recognized. If this value is null, then a system default is used.

Throws:

IOException - If an error occurs when trying to read a BOM.

read

public int read(char[] cbuf,
       int off,
       int len)
         throws IOException

Read characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

Specified by:

read in class Reader

Parameters:

cbuf - The buffer into which to read.

off - The offset at which to start storing characters.

len - The 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