org.apache.derbyTesting.functionTests.util.streams
Class ByteAlphabet

java.lang.Object
  org.apache.derbyTesting.functionTests.util.streams.ByteAlphabet

public class ByteAlphabet
extends java.lang.Object

A looping alphabet, returning bytes in a specified encoding. The alphabet loops over a list of bytes representing characters. The alphabet-object is used by looping stream, which in turn is used for testing methods requiring streaming inputs. The following alphabets have been defined:

• Modern latin, lowercase ; letters a - z (26)
• Norwegian/Danish, lowercase ; letters a - z, plus three additional letters (29)
• Tamil ; 46 Tamil letters from UNICODE U0B80
• CJK subset ; 12 letter from UNICODE CJK U4E00

Field Summary

private int	boff Offset into the byte array.
private int	byteCount The number of byes in the alphabet.
private byte[]	bytes The bytes representing the characters in the alphabet.
private int	charCount The number of characters in the alphabet.
private java.lang.String	encoding The encoding used to represent characters as bytes.
private java.lang.String	name The name of the alphabet.

Constructor Summary

private

ByteAlphabet(java.lang.String name, char[] chars, java.lang.String encoding) Create an alphabet with the given name, the given characters and using the specified encoding to represent the characters as bytes.

Method Summary

int	byteCount() Return the number of bytes in the alphabet.
int	charCount() Return the number of characters in the alphabet.
static ByteAlphabet	cjkSubsetUTF16BE() Create an alphabet returning bytes representing a subset of the CJK alphabet in the UTF-16BE encoding.
static ByteAlphabet	cjkSubsetUTF8() Create an alphabet returning bytes representing a subset of the CJK alphabet in the UTF-8 encoding.
java.lang.String	getEncoding() Return the encoding used to represent characters as bytes.
java.lang.String	getName() Return the name of the alphabet.
static ByteAlphabet	modernLatinLowercase() Create an alphabet returning bytes representing the lowercase letters a-z in the "US-ASCII" encoding.
byte	nextByte() Return the next byte in the alphabet.
int	nextByteToRead(int bytesRead) Compute the next byte to read after reading the specified number of bytes.
static ByteAlphabet	norwegianLowercase() Create an alphabet returning bytes representing the 29 lowercase letters in the Norwegian/Danish alphabet in the "ISO-8859-1" encoding.
void	reset() Reset the alphabet, the next byte returned is the first byte in the alphabet, which might not be a complete character.
static ByteAlphabet	tamilUTF16BE() Create an alphabet returning bytes representing a subset of the Tamil alphabet in the UTF-16BE encoding.
static ByteAlphabet	tamilUTF8() Create an alphabet returning bytes representing a subset of the Tamil alphabet in the UTF-8 encoding.

Methods inherited from class java.lang.Object

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

Field Detail

name

private final java.lang.String name

The name of the alphabet.

encoding

private final java.lang.String encoding

The encoding used to represent characters as bytes.

bytes

private final byte[] bytes

The bytes representing the characters in the alphabet.

charCount

private final int charCount

The number of characters in the alphabet.

byteCount

private final int byteCount

The number of byes in the alphabet.

boff

private int boff

Offset into the byte array.

Constructor Detail

ByteAlphabet

private ByteAlphabet(java.lang.String name,
                     char[] chars,
                     java.lang.String encoding)

Create an alphabet with the given name, the given characters and using the specified encoding to represent the characters as bytes.

Parameters:

name - the name of the alphabet

chars - the characters in the alphabet

encoding - the encoding to use to represent characters as bytes

Method Detail

modernLatinLowercase

public static ByteAlphabet modernLatinLowercase()

Create an alphabet returning bytes representing the lowercase letters a-z in the "US-ASCII" encoding.

norwegianLowercase

public static ByteAlphabet norwegianLowercase()

Create an alphabet returning bytes representing the 29 lowercase letters in the Norwegian/Danish alphabet in the "ISO-8859-1" encoding.

tamilUTF8

public static ByteAlphabet tamilUTF8()

Create an alphabet returning bytes representing a subset of the Tamil alphabet in the UTF-8 encoding.

tamilUTF16BE

public static ByteAlphabet tamilUTF16BE()

Create an alphabet returning bytes representing a subset of the Tamil alphabet in the UTF-16BE encoding.

cjkSubsetUTF8

public static ByteAlphabet cjkSubsetUTF8()

Create an alphabet returning bytes representing a subset of the CJK alphabet in the UTF-8 encoding.

cjkSubsetUTF16BE

public static ByteAlphabet cjkSubsetUTF16BE()

Create an alphabet returning bytes representing a subset of the CJK alphabet in the UTF-16BE encoding.

getName

public java.lang.String getName()

Return the name of the alphabet.

getEncoding

public java.lang.String getEncoding()

Return the encoding used to represent characters as bytes.

charCount

public int charCount()

Return the number of characters in the alphabet.

byteCount

public int byteCount()

Return the number of bytes in the alphabet. The number of bytes in the alphabet is noramlly different from the number of characters in the alphabet, but it depends on the characters in the alphabet and encoding used to represent them as bytes.

nextByte

public byte nextByte()

Return the next byte in the alphabet.

reset

public void reset()

Reset the alphabet, the next byte returned is the first byte in the alphabet, which might not be a complete character.

nextByteToRead

public int nextByteToRead(int bytesRead)

Compute the next byte to read after reading the specified number of bytes. Besides from returning the index, the internal state of the alphabet is updated.

Parameters:

bytesRead - the number of bytes read

Returns:

the index of the next byte