net.sf.saxon.regex

Class UnicodeString

java.lang.Object

net.sf.saxon.regex.UnicodeString

All Implemented Interfaces:

CharSequence, Comparable<UnicodeString>

Direct Known Subclasses:

BMPString, EmptyString, GeneralUnicodeString, LatinString

public abstract class UnicodeString
extends Object
implements CharSequence, Comparable<UnicodeString>

An abstract class that efficiently handles Unicode strings including non-BMP characters; it has three subclasses, respectively handling strings whose maximum character code is 255, 65535, or 1114111.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) int	cachedHash

Constructor Summary

Constructors

Constructor and Description
UnicodeString()

Method Summary

Modifier and Type	Method and Description
int	compareTo(UnicodeString other) Compare two unicode strings in codepoint collating sequence
static boolean	containsSurrogatePairs(CharSequence value) Test whether a CharSequence contains Unicode codepoints outside the BMP range
boolean	equals(Object obj) Implementations of UnicodeString can be compared with each other, but not with other implementations of CharSequence
byte[]	getCodepointCollationKey() Get the codepoints of the string as a byte array, allocating three bytes per character.
static int	getMaxWidth(CharSequence value) Get the maximum width of codepoints in this string, in bytes
int	hashCode() Implementations of UnicodeString can be compared with each other, but not with other implementations of CharSequence
abstract boolean	isEnd(int pos) Ask whether a given position is at (or beyond) the end of the string
static UnicodeString	makeUnicodeString(CharSequence in) Make a UnicodeString for a given CharSequence
static UnicodeString	makeUnicodeString(int[] in) Make a UnicodeString for a given array of codepoints
abstract int	uCharAt(int pos) Get the character at a specified position
abstract int	uIndexOf(int search, int start) Get the first match for a given character
abstract int	uLength() Get the length of the string, in Unicode codepoints
abstract UnicodeString	uSubstring(int beginIndex, int endIndex) Get a substring of this string

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.CharSequence

charAt, chars, codePoints, length, subSequence, toString

Field Detail

cachedHash

int cachedHash

Constructor Detail

UnicodeString

public UnicodeString()

Method Detail

makeUnicodeString

public static UnicodeString makeUnicodeString(CharSequence in)

Make a UnicodeString for a given CharSequence

Parameters:

in - the input CharSequence

Returns:

a UnicodeString using an appropriate implementation class

makeUnicodeString

public static UnicodeString makeUnicodeString(int[] in)

Make a UnicodeString for a given array of codepoints

Parameters:

in - the input CharSequence

Returns:

a UnicodeString using an appropriate implementation class

containsSurrogatePairs

public static boolean containsSurrogatePairs(CharSequence value)

Test whether a CharSequence contains Unicode codepoints outside the BMP range

Parameters:

value - the string to be tested

Returns:

true if the string contains non-BMP codepoints

getMaxWidth

public static int getMaxWidth(CharSequence value)

Get the maximum width of codepoints in this string, in bytes

Parameters:

value - the string to be examined

Returns:

1, 2, or 4 depending on whether the string contains characters with codepoints >255 and/or >65535

uSubstring

public abstract UnicodeString uSubstring(int beginIndex,
                                         int endIndex)

Get a substring of this string

Parameters:

beginIndex - the index of the first character to be included (counting codepoints, not 16-bit characters)

endIndex - the index of the first character to be NOT included (counting codepoints, not 16-bit characters)

Returns:

a substring

Throws:

IndexOutOfBoundsException - if the selection goes off the start or end of the string (this function follows the semantics of String.substring(), not the XPath semantics)

uIndexOf

public abstract int uIndexOf(int search,
                             int start)

Get the first match for a given character

Parameters:

search - the character to look for

start - the first position to look

Returns:

the position of the first occurrence of the sought character, or -1 if not found

uCharAt

public abstract int uCharAt(int pos)

Get the character at a specified position

Parameters:

pos - the index of the required character (counting codepoints, not 16-bit characters)

Returns:

a character (Unicode codepoint) at the specified position.

uLength

public abstract int uLength()

Get the length of the string, in Unicode codepoints

Returns:

the number of codepoints in the string

isEnd

public abstract boolean isEnd(int pos)

Ask whether a given position is at (or beyond) the end of the string

Parameters:

pos - the index of the required character (counting codepoints, not 16-bit characters)

Returns:

true iff if the specified index is after the end of the character stream

hashCode

public int hashCode()

Implementations of UnicodeString can be compared with each other, but not with other implementations of CharSequence

Overrides:

hashCode in class Object

Returns:

a hashCode that distinuishes this UnicodeString from others

equals

public boolean equals(Object obj)

Implementations of UnicodeString can be compared with each other, but not with other implementations of CharSequence

Overrides:

equals in class Object

Parameters:

obj - the object to be compared

Returns:

true if obj is a UnicodeString containing the same codepoints

compareTo

public int compareTo(UnicodeString other)

Compare two unicode strings in codepoint collating sequence

Specified by:

compareTo in interface Comparable<UnicodeString>

Parameters:

other - the object to be compared

Returns:

less than 0, 0, or greater than 0 depending on the ordering of the two strings

getCodepointCollationKey

public final byte[] getCodepointCollationKey()

Get the codepoints of the string as a byte array, allocating three bytes per character. (Max unicode codepoint = x10FFFF)

Returns:

a byte array that can act as a collation key