org.apache.xerces.impl.io

Class UCSReader

java.lang.Object

java.io.Reader

org.apache.xerces.impl.io.UCSReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

public final class UCSReader
extends Reader

Reader for UCS-2 and UCS-4 encodings. (i.e., encodings from ISO-10646-UCS-(2|4)).

Version:

$Id$

Author:

Neil Graham, IBM

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_BUFFER_SIZE Default byte buffer size (8192, larger than that of ASCIIReader since it's reasonable to surmise that the average UCS-4-encoded file should be 4 times as large as the average ASCII-encoded file).
protected byte[]	fBuffer Byte buffer.
protected short	fEncoding
protected InputStream	fInputStream Input stream.
static short	UCS2BE
static short	UCS2LE
static short	UCS4BE
static short	UCS4LE

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor and Description
UCSReader(InputStream inputStream, byte[] buffer, short encoding) Constructs a UCS reader from the specified input stream and buffer.
UCSReader(InputStream inputStream, int size, short encoding) Constructs a UCS reader from the specified input stream and buffer size.
UCSReader(InputStream inputStream, short encoding) Constructs a UCS reader from the specified input stream using the default buffer size.

Method Summary

Methods

Modifier and Type	Method and Description
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[] ch, int offset, int length) 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, read

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_BUFFER_SIZE

public static final int DEFAULT_BUFFER_SIZE

Default byte buffer size (8192, larger than that of ASCIIReader since it's reasonable to surmise that the average UCS-4-encoded file should be 4 times as large as the average ASCII-encoded file).

See Also:

Constant Field Values

UCS2LE

public static final short UCS2LE

See Also:

Constant Field Values

UCS2BE

public static final short UCS2BE

See Also:

Constant Field Values

UCS4LE

public static final short UCS4LE

See Also:

Constant Field Values

UCS4BE

public static final short UCS4BE

See Also:

Constant Field Values

fInputStream

protected final InputStream fInputStream

Input stream.

fBuffer

protected final byte[] fBuffer

Byte buffer.

fEncoding

protected final short fEncoding

Constructor Detail

UCSReader

public UCSReader(InputStream inputStream,
         short encoding)

Constructs a UCS reader from the specified input stream using the default buffer size. The Endian-ness and whether this is UCS-2 or UCS-4 needs also to be known in advance.

Parameters:

inputStream - The input stream.

encoding - One of UCS2LE, UCS2BE, UCS4LE or UCS4BE.

UCSReader

public UCSReader(InputStream inputStream,
         int size,
         short encoding)

Constructs a UCS reader from the specified input stream and buffer size. The Endian-ness and whether this is UCS-2 or UCS-4 needs also to be known in advance.

Parameters:

inputStream - The input stream.

size - The initial buffer size.

encoding - One of UCS2LE, UCS2BE, UCS4LE or UCS4BE.

UCSReader

public UCSReader(InputStream inputStream,
         byte[] buffer,
         short encoding)

Constructs a UCS reader from the specified input stream and buffer. The Endian-ness and whether this is UCS-2 or UCS-4 needs also to be known in advance.

Parameters:

inputStream - The input stream.

buffer - The byte buffer.

encoding - One of UCS2LE, UCS2BE, UCS4LE or UCS4BE.

Method Detail

read

public int read()
         throws IOException

Read a single character. This method will block until a character is available, an I/O error occurs, or the end of the stream is reached.

Subclasses that intend to support efficient single-character input should override this method.

Overrides:

read in class Reader

Returns:

The character read, as an integer in the range 0 to 127 (0x00-0x7f), or -1 if the end of the stream has been reached

Throws:

IOException - If an I/O error occurs

read

public int read(char[] ch,
       int offset,
       int length)
         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:

ch - 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

Throws:

IOException - If an I/O error occurs

skip

public long skip(long n)
          throws IOException

Skip characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.

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

mark

public void mark(int readAheadLimit)
          throws IOException

Mark the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point. Not all character-input streams support the mark() operation.

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

reset

public void reset()
           throws IOException

Reset the stream. If the stream has been marked, then attempt to reposition it at the mark. If the stream has not been marked, then attempt to reset it in some way appropriate to the particular stream, for example by repositioning it to its starting point. Not all character-input streams support the reset() operation, and some support reset() without supporting mark().

Overrides:

reset in class Reader

Throws:

IOException - If the stream has not been marked, or if the mark has been invalidated, or if the stream does not support reset(), or if some other I/O error occurs

close

public void close()
           throws IOException

Close the stream. Once a stream has been closed, further read(), ready(), mark(), or reset() invocations will throw an IOException. Closing a previously-closed stream, however, has no effect.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class Reader

Throws:

IOException - If an I/O error occurs