com.ibm.icu.text

Class UTF16.StringComparator

Enclosing Class:
UTF16
Implemented Interfaces:
Comparator

public static final class UTF16.StringComparator
extends Object
implements Comparator

UTF16 string comparator class. Allows UTF16 string comparison to be done with the various modes

The code unit or code point comparison differ only when comparing supplementary code points (\u10000..\u10ffff) to BMP code points near the end of the BMP (i.e., \ue000..\uffff). In code unit comparison, high BMP code points sort after supplementary code points because they are stored as pairs of surrogates which are at \ud800..\udfff.

See Also:
FOLD_CASE_DEFAULT, FOLD_CASE_EXCLUDE_SPECIAL_I

Field Summary

static int
FOLD_CASE_DEFAULT
Option value for case folding comparison:

Comparison is case insensitive, strings are folded using default mappings defined in Unicode data file CaseFolding.txt, before comparison.

static int
FOLD_CASE_EXCLUDE_SPECIAL_I
Option value for case folding comparison:

Comparison is case insensitive, strings are folded using modified mappings defined in Unicode data file CaseFolding.txt, before comparison.

Constructor Summary

StringComparator()
Default constructor that does code unit comparison and case sensitive comparison.
StringComparator(boolean codepointcompare, boolean ignorecase, int foldcaseoption)
Constructor that does comparison based on the argument options.

Method Summary

int
compare(Object a, Object b)
Compare two strings depending on the options selected during construction.
boolean
getCodePointCompare()
Checks if the comparison mode is code point compare.
boolean
getIgnoreCase()
Checks if Comparator is in the case insensitive mode.
int
getIgnoreCaseOption()
Gets the fold case options set in Comparator to be used with case insensitive comparison.
void
setCodePointCompare(boolean flag)
Sets the comparison mode to code point compare if flag is true.
void
setIgnoreCase(boolean ignorecase, int foldcaseoption)
Sets the Comparator to case-insensitive comparison mode if argument is true, otherwise case sensitive comparison mode if set to false.

Field Details

FOLD_CASE_DEFAULT

public static final int FOLD_CASE_DEFAULT
Option value for case folding comparison:

Comparison is case insensitive, strings are folded using default mappings defined in Unicode data file CaseFolding.txt, before comparison.

Field Value:
0

FOLD_CASE_EXCLUDE_SPECIAL_I

public static final int FOLD_CASE_EXCLUDE_SPECIAL_I
Option value for case folding comparison:

Comparison is case insensitive, strings are folded using modified mappings defined in Unicode data file CaseFolding.txt, before comparison.

The modified set of mappings is provided in a Unicode data file CaseFolding.txt to handle dotted I and dotless i appropriately for Turkic languages (tr, az).

Before Unicode 3.2, CaseFolding.txt contains mappings marked with 'I' that are to be included for default mappings and excluded for the Turkic-specific mappings.

Unicode 3.2 CaseFolding.txt instead contains mappings marked with 'T' that are to be excluded for default mappings and included for the Turkic-specific mappings.

Field Value:
1

Constructor Details

StringComparator

public StringComparator()
Default constructor that does code unit comparison and case sensitive comparison.

StringComparator

public StringComparator(boolean codepointcompare,
                        boolean ignorecase,
                        int foldcaseoption)
Constructor that does comparison based on the argument options.
Parameters:
codepointcompare - flag to indicate true for code point comparison or false for code unit comparison.
ignorecase - false for case sensitive comparison, true for case-insensitive comparison
foldcaseoption - FOLD_CASE_DEFAULT or FOLD_CASE_EXCLUDE_SPECIAL_I. This option is used only when ignorecase is set to true. If ignorecase is false, this option is ignored.

Method Details

compare

public int compare(Object a,
                   Object b)
Compare two strings depending on the options selected during construction.
Parameters:
a - first source string.
b - second source string.
Returns:
0 returned if a == b. If a <32b, a negative value is returned. Otherwise if a > b, a positive value is returned.

getCodePointCompare

public boolean getCodePointCompare()
Checks if the comparison mode is code point compare.
Returns:
true for code point compare, false for code unit compare

getIgnoreCase

public boolean getIgnoreCase()
Checks if Comparator is in the case insensitive mode.
Returns:
true if Comparator performs case insensitive comparison, false otherwise

getIgnoreCaseOption

public int getIgnoreCaseOption()
Gets the fold case options set in Comparator to be used with case insensitive comparison.
Returns:
either FOLD_CASE_DEFAULT or FOLD_CASE_EXCLUDE_SPECIAL_I

setCodePointCompare

public void setCodePointCompare(boolean flag)
Sets the comparison mode to code point compare if flag is true. Otherwise comparison mode is set to code unit compare
Parameters:
flag - true for code point compare, false for code unit compare

setIgnoreCase

public void setIgnoreCase(boolean ignorecase,
                          int foldcaseoption)
Sets the Comparator to case-insensitive comparison mode if argument is true, otherwise case sensitive comparison mode if set to false.
Parameters:
ignorecase - true for case-insitive comparison, false for case sensitive comparison
foldcaseoption - FOLD_CASE_DEFAULT or FOLD_CASE_EXCLUDE_SPECIAL_I. This option is used only when ignorecase is set to true. If ignorecase is false, this option is ignored.

Copyright (c) 2006 IBM Corporation and others.