com.ibm.icu.text

Class UTF16.StringComparator

java.lang.Object

com.ibm.icu.text.UTF16.StringComparator

All Implemented Interfaces:

Comparator<String>

Enclosing class:

UTF16

public static final class UTF16.StringComparator
extends Object
implements Comparator<String>

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

• Code point comparison or code unit comparison
• Case sensitive comparison, case insensitive comparison or case insensitive comparison with special handling for character 'i'.

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

Fields

Modifier and Type	Field and Description
static int	FOLD_CASE_DEFAULT Option value for case folding comparison:
static int	FOLD_CASE_EXCLUDE_SPECIAL_I Option value for case folding: Use the modified set of mappings provided in CaseFolding.txt to handle dotted I and dotless i appropriately for Turkic languages (tr, az).

Constructor Summary

Constructors

Constructor and Description
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

Modifier and Type	Method and Description
int	compare(String a, String 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.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Field Detail

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.

See Also:

Constant Field Values

FOLD_CASE_EXCLUDE_SPECIAL_I

public static final int FOLD_CASE_EXCLUDE_SPECIAL_I

Option value for case folding: Use the modified set of mappings provided in CaseFolding.txt to handle dotted I and dotless i appropriately for Turkic languages (tr, az).

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

See Also:

UCharacter.FOLD_CASE_EXCLUDE_SPECIAL_I, Constant Field Values

Constructor Detail

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.

Throws:

IllegalArgumentException - If foldcaseoption is out of range

See Also:

FOLD_CASE_DEFAULT, FOLD_CASE_EXCLUDE_SPECIAL_I

Method Detail

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.

See Also:

FOLD_CASE_DEFAULT, FOLD_CASE_EXCLUDE_SPECIAL_I

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

See Also:

FOLD_CASE_DEFAULT, FOLD_CASE_EXCLUDE_SPECIAL_I

compare

public int compare(String a,
                   String b)

Compare two strings depending on the options selected during construction.

Specified by:

compare in interface Comparator<String>

Parameters:

a - first source string.

b - second source string.

Returns:

0 returned if a == b. If a < b, a negative value is returned. Otherwise if a > b, a positive value is returned.

Throws:

ClassCastException - thrown when either a or b is not a String object