org.apache.xerces.impl.io
Class UCSReader

java.lang.Object
  extended by java.io.Reader
      extended by org.apache.xerces.impl.io.UCSReader
All Implemented Interfaces:
java.io.Closeable, java.lang.Readable

public class UCSReader
extends java.io.Reader

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

Version:
$Id: UCSReader.java 449317 2006-09-23 22:12:30Z mrglavas $
Author:
Neil Graham, IBM

Field Summary
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).
static short UCS2BE
           
static short UCS2LE
           
static short UCS4BE
           
static short UCS4LE
           
 
Constructor Summary
UCSReader(java.io.InputStream inputStream, byte[] buffer, short encoding)
          Constructs a UCS reader from the specified input stream and buffer.
UCSReader(java.io.InputStream inputStream, int size, short encoding)
          Constructs a UCS reader from the specified input stream and buffer size.
UCSReader(java.io.InputStream inputStream, short encoding)
          Constructs a UCS reader from the specified input stream using the default buffer size.
 
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[] 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
equals, 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
Constructor Detail

UCSReader

public UCSReader(java.io.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(java.io.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(java.io.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 java.io.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 java.io.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:
java.io.IOException - If an I/O error occurs

read

public int read(char[] ch,
                int offset,
                int length)
         throws java.io.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 java.io.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:
java.io.IOException - If an I/O error occurs

skip

public long skip(long n)
          throws java.io.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 java.io.Reader
Parameters:
n - The number of characters to skip
Returns:
The number of characters actually skipped
Throws:
java.io.IOException - If an I/O error occurs

ready

public boolean ready()
              throws java.io.IOException
Tell whether this stream is ready to be read.

Overrides:
ready in class java.io.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:
java.io.IOException - If an I/O error occurs

markSupported

public boolean markSupported()
Tell whether this stream supports the mark() operation.

Overrides:
markSupported in class java.io.Reader

mark

public void mark(int readAheadLimit)
          throws java.io.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 java.io.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:
java.io.IOException - If the stream does not support mark(), or if some other I/O error occurs

reset

public void reset()
           throws java.io.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 java.io.Reader
Throws:
java.io.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 java.io.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 java.io.Closeable
Specified by:
close in class java.io.Reader
Throws:
java.io.IOException - If an I/O error occurs