ICU 70.1 70.1

Public Types | Public Member Functions | Static Public Member Functions | Protected Member Functions | Friends
icu::Collator Class Referenceabstract

The `Collator` class performs locale-sensitive string comparison. More...

`#include <coll.h>`

Inheritance diagram for icu::Collator:

## Public Types
enum | ECollationStrength { PRIMARY = UCOL_PRIMARY , SECONDARY = UCOL_SECONDARY , TERTIARY = UCOL_TERTIARY , QUATERNARY = UCOL_QUATERNARY , IDENTICAL = UCOL_IDENTICAL }
| Base letter represents a primary difference. More...
enum | EComparisonResult { LESS = UCOL_LESS , EQUAL = UCOL_EQUAL , GREATER = UCOL_GREATER }
| LESS is returned if source string is compared to be less than target string in the compare() method. More...

## Public Member Functions
virtual | ~Collator ()
| Destructor. More...
virtual bool | operator== (const Collator &other) const
| Returns true if "other" is the same as "this". More...
virtual bool | operator!= (const Collator &other) const
| Returns true if "other" is not the same as "this". More...
virtual Collator * | clone () const =0
| Makes a copy of this object. More...
virtual EComparisonResult | compare (const UnicodeString &source, const UnicodeString &target) const
| The comparison function compares the character data stored in two different strings. More...
virtual UCollationResult | compare (const UnicodeString &source, const UnicodeString &target, UErrorCode &status) const =0
| The comparison function compares the character data stored in two different strings. More...
virtual EComparisonResult | compare (const UnicodeString &source, const UnicodeString &target, int32_t length) const
| Does the same thing as compare but limits the comparison to a specified length. More...
virtual UCollationResult | compare (const UnicodeString &source, const UnicodeString &target, int32_t length, UErrorCode &status) const =0
| Does the same thing as compare but limits the comparison to a specified length. More...
virtual EComparisonResult | compare (const char16_t *source, int32_t sourceLength, const char16_t *target, int32_t targetLength) const
| The comparison function compares the character data stored in two different string arrays. More...
virtual UCollationResult | compare (const char16_t *source, int32_t sourceLength, const char16_t *target, int32_t targetLength, UErrorCode &status) const =0
| The comparison function compares the character data stored in two different string arrays. More...
virtual UCollationResult | compare (UCharIterator &sIter, UCharIterator &tIter, UErrorCode &status) const
| Compares two strings using the Collator. More...
virtual UCollationResult | compareUTF8 (const StringPiece &source, const StringPiece &target, UErrorCode &status) const
| Compares two UTF-8 strings using the Collator. More...
virtual CollationKey & | getCollationKey (const UnicodeString &source, CollationKey &key, UErrorCode &status) const =0
| Transforms the string into a series of characters that can be compared with CollationKey::compareTo. More...
virtual CollationKey & | getCollationKey (const char16_t *source, int32_t sourceLength, CollationKey &key, UErrorCode &status) const =0
| Transforms the string into a series of characters that can be compared with CollationKey::compareTo. More...
virtual int32_t | hashCode (void) const =0
| Generates the hash code for the collation object. More...
virtual Locale | getLocale (ULocDataLocaleType type, UErrorCode &status) const =0
| Gets the locale of the Collator. More...
UBool | greater (const UnicodeString &source, const UnicodeString &target) const
| Convenience method for comparing two strings based on the collation rules. More...
UBool | greaterOrEqual (const UnicodeString &source, const UnicodeString &target) const
| Convenience method for comparing two strings based on the collation rules. More...
UBool | equals (const UnicodeString &source, const UnicodeString &target) const
| Convenience method for comparing two strings based on the collation rules. More...
virtual ECollationStrength | getStrength (void) const
| Determines the minimum strength that will be used in comparison or transformation. More...
virtual void | setStrength (ECollationStrength newStrength)
| Sets the minimum strength to be used in comparison or transformation. More...
virtual int32_t | getReorderCodes (int32_t *dest, int32_t destCapacity, UErrorCode &status) const
| Retrieves the reordering codes for this collator. More...
virtual void | setReorderCodes (const int32_t *reorderCodes, int32_t reorderCodesLength, UErrorCode &status)
| Sets the ordering of scripts for this collator. More...
virtual void | getVersion (UVersionInfo info) const =0
| Gets the version information for a Collator. More...
virtual UClassID | getDynamicClassID (void) const override=0
| Returns a unique class ID POLYMORPHICALLY. More...
virtual void | setAttribute (UColAttribute attr, UColAttributeValue value, UErrorCode &status)=0
| Universal attribute setter. More...
virtual UColAttributeValue | getAttribute (UColAttribute attr, UErrorCode &status) const =0
| Universal attribute getter. More...
virtual Collator & | setMaxVariable (UColReorderCode group, UErrorCode &errorCode)
| Sets the variable top to the top of the specified reordering group. More...
virtual UColReorderCode | getMaxVariable () const
| Returns the maximum reordering group whose characters are affected by UCOL_ALTERNATE_HANDLING. More...
virtual uint32_t | setVariableTop (const char16_t *varTop, int32_t len, UErrorCode &status)=0
| Sets the variable top to the primary weight of the specified string. More...
virtual uint32_t | setVariableTop (const UnicodeString &varTop, UErrorCode &status)=0
| Sets the variable top to the primary weight of the specified string. More...
virtual void | setVariableTop (uint32_t varTop, UErrorCode &status)=0
| Sets the variable top to the specified primary weight. More...
virtual uint32_t | getVariableTop (UErrorCode &status) const =0
| Gets the variable top value of a Collator. More...
virtual UnicodeSet * | getTailoredSet (UErrorCode &status) const
| Get a UnicodeSet that contains all the characters and sequences tailored in this collator. More...
virtual Collator * | safeClone () const
| Same as clone(). More...
virtual int32_t | getSortKey (const UnicodeString &source, uint8_t *result, int32_t resultLength) const =0
| Get the sort key as an array of bytes from a UnicodeString. More...
virtual int32_t | getSortKey (const char16_t *source, int32_t sourceLength, uint8_t *result, int32_t resultLength) const =0
| Get the sort key as an array of bytes from a char16_t buffer. More...
virtual void | setLocales (const Locale &requestedLocale, const Locale &validLocale, const Locale &actualLocale)
| Used internally by registration to define the requested and valid locales. More...
virtual int32_t | internalGetShortDefinitionString (const char *locale, char *buffer, int32_t capacity, UErrorCode &status) const
| Get the short definition string for a collator. More...
virtual UCollationResult | internalCompareUTF8 (const char *left, int32_t leftLength, const char *right, int32_t rightLength, UErrorCode &errorCode) const
| Implements ucol_strcollUTF8(). More...
virtual int32_t | internalNextSortKeyPart (UCharIterator *iter, uint32_t state[2], uint8_t *dest, int32_t count, UErrorCode &errorCode) const
| Implements ucol_nextSortKeyPart(). More...
UCollator * | toUCollator ()
const UCollator * | toUCollator () const
Public Member Functions inherited from icu::UObject
virtual | ~UObject ()
| Destructor. More...

## Static Public Member Functions
static Collator * | createInstance (UErrorCode &err)
| Creates the Collator object for the current default locale. More...
static Collator * | createInstance (const Locale &loc, UErrorCode &err)
| Gets the collation object for the desired locale. More...
static int32_t | getEquivalentReorderCodes (int32_t reorderCode, int32_t *dest, int32_t destCapacity, UErrorCode &status)
| Retrieves the reorder codes that are grouped with the given reorder code. More...
static UnicodeString & | getDisplayName (const Locale &objectLocale, const Locale &displayLocale, UnicodeString &name)
| Get name of the object for the desired Locale, in the desired language. More...
static UnicodeString & | getDisplayName (const Locale &objectLocale, UnicodeString &name)
| Get name of the object for the desired Locale, in the language of the default locale. More...
static const Locale * | getAvailableLocales (int32_t &count)
| Get the set of Locales for which Collations are installed. More...
static StringEnumeration * | getAvailableLocales (void)
| Return a StringEnumeration over the locales available at the time of the call, including registered locales. More...
static StringEnumeration * | getKeywords (UErrorCode &status)
| Create a string enumerator of all possible keywords that are relevant to collation. More...
static StringEnumeration * | getKeywordValues (const char *keyword, UErrorCode &status)
| Given a keyword, create a string enumeration of all values for that keyword that are currently in use. More...
static StringEnumeration * | getKeywordValuesForLocale (const char *keyword, const Locale &locale, UBool commonlyUsed, UErrorCode &status)
| Given a key and a locale, returns an array of string values in a preferred order that would make a difference. More...
static Locale | getFunctionalEquivalent (const char *keyword, const Locale &locale, UBool &isAvailable, UErrorCode &status)
| Return the functionally equivalent locale for the given requested locale, with respect to given keyword, for the collation service. More...
static URegistryKey | registerInstance (Collator *toAdopt, const Locale &locale, UErrorCode &status)
| Register a new Collator. More...
static URegistryKey | registerFactory (CollatorFactory *toAdopt, UErrorCode &status)
| Register a new CollatorFactory. More...
static UBool | unregister (URegistryKey key, UErrorCode &status)
| Unregister a previously-registered Collator or CollatorFactory using the key returned from the register call. More...
static int32_t | getBound (const uint8_t *source, int32_t sourceLength, UColBoundMode boundType, uint32_t noOfLevels, uint8_t *result, int32_t resultLength, UErrorCode &status)
| Produce a bound for a given sortkey and a number of levels. More...
static Collator * | fromUCollator (UCollator *uc)
static const Collator * | fromUCollator (const UCollator *uc)

## Protected Member Functions
| Collator ()
| Default constructor. More...
| Collator (UCollationStrength collationStrength, UNormalizationMode decompositionMode)
| Constructor. More...
| Collator (const Collator &other)
| Copy constructor. More...

## Friends
class | CFactory
class | SimpleCFactory
class | ICUCollatorFactory
class | ICUCollatorService

## Detailed Description

The `Collator` class performs locale-sensitive string comparison.

You use this class to build searching and sorting routines for natural language text.

`Collator` is an abstract base class. Subclasses implement specific collation strategies. One subclass, `RuleBasedCollator`, is currently provided and is applicable to a wide set of languages. Other subclasses may be created to handle more specialized needs.

Like other locale-sensitive classes, you can use the static factory method, `createInstance`, to obtain the appropriate `Collator` object for a given locale. You will only need to look at the subclasses of `Collator` if you need to understand the details of a particular collation strategy or if you need to modify that strategy.

The following example shows how to compare two strings using the `Collator` for the default locale.

>     // Compare two strings in the default locale
>     UErrorCode success = U_ZERO_ERROR;
>     Collator* myCollator = Collator::createInstance(success);
>     if (myCollator->compare("abc", "ABC") < 0)
>       cout << "abc is less than ABC" << endl;
>     else
>       cout << "abc is greater than or equal to ABC" << endl;
>     icu::Collator::createInstancestatic Collator * createInstance(UErrorCode &err)Creates the Collator object for the current default locale.
>     icu::Collator::CollatorCollator()Default constructor.
>     UErrorCodeUErrorCodeStandard ICU4C error code type, a substitute for exceptions.Definition: utypes.h:415
>     U_ZERO_ERROR@ U_ZERO_ERRORNo error, no warning.Definition: utypes.h:449

You can set a `Collator`'s strength attribute to determine the level of difference considered significant in comparisons. Five strengths are provided: `PRIMARY`, `SECONDARY`, `TERTIARY`, `QUATERNARY` and `IDENTICAL`. The exact assignment of strengths to language features is locale dependent. For example, in Czech, "e" and "f" are considered primary differences, while "e" and "\u00EA" are secondary differences, "e" and "E" are tertiary differences and "e" and "e" are identical. The following shows how both case and accents could be ignored for US English.

>     //Get the Collator for US English and set its strength to PRIMARY
>     UErrorCode success = U_ZERO_ERROR;
>     Collator* usCollator = Collator::createInstance(Locale::getUS(), success);
>     usCollator->setStrength(Collator::PRIMARY);
>     if (usCollator->compare("abc", "ABC") == 0)
>         cout << "'abc' and 'ABC' strings are equivalent with strength PRIMARY" << endl;
>     icu::Locale::getUSstatic const Locale & getUS(void)Useful constant for this country/region.

The `getSortKey` methods convert a string to a series of bytes that can be compared bitwise against other sort keys using `strcmp()`. Sort keys are written as zero-terminated byte strings.

Another set of APIs returns a `CollationKey` object that wraps the sort key bytes instead of returning the bytes themselves.

Note: `Collator`s with different Locale, and CollationStrength settings will return different sort orders for the same set of strings. Locales have specific collation rules, and the way in which secondary and tertiary differences are taken into account, for example, will result in a different sorting order for same strings.

See also
  RuleBasedCollator
  CollationKey
  CollationElementIterator
  Locale
  Normalizer2

Version
  2.0 11/15/01

Definition at line 167 of file coll.h.

## Member Enumeration Documentation

## ◆ ECollationStrength

enum icu::Collator::ECollationStrength

Base letter represents a primary difference.

Set comparison level to PRIMARY to ignore secondary and tertiary differences.
Use this to set the strength of a Collator object.
Example of primary difference, "abc" < "abd"

Diacritical differences on the same base letter represent a secondary difference. Set comparison level to SECONDARY to ignore tertiary differences. Use this to set the strength of a Collator object.
Example of secondary difference, "&auml;" >> "a".

Uppercase and lowercase versions of the same character represents a tertiary difference. Set comparison level to TERTIARY to include all comparison differences. Use this to set the strength of a Collator object.
Example of tertiary difference, "abc" <<< "ABC".

Two characters are considered "identical" when they have the same unicode spellings.
For example, "&auml;" == "&auml;".

UCollationStrength is also used to determine the strength of sort keys generated from Collator objects.

Stable:
  ICU 2.0

Definition at line 197 of file coll.h.

## ◆ EComparisonResult

enum icu::Collator::EComparisonResult

LESS is returned if source string is compared to be less than target string in the compare() method.

EQUAL is returned if source string is compared to be equal to target string in the compare() method. GREATER is returned if source string is compared to be greater than target string in the compare() method.

See also
  Collator::compare

Deprecated:
  ICU 2.6. Use C enum UCollationResult defined in ucol.h

Definition at line 220 of file coll.h.

## Constructor & Destructor Documentation

## ◆ ~Collator()

virtual icu::Collator::~Collator | ( |  | ) |
| virtual

Destructor.

Stable:
  ICU 2.0

## ◆ Collator() [1/3]

icu::Collator::Collator | ( |  | ) |
| protected

Default constructor.

Constructor is different from the old default Collator constructor. The task for determining the default collation strength and normalization mode is left to the child class.

Stable:
  ICU 2.0

## ◆ Collator() [2/3]

icu::Collator::Collator | ( | UCollationStrength | collationStrength,
|  | UNormalizationMode | decompositionMode
| ) |  |
| protected

Constructor.

Empty constructor, does not handle the arguments. This constructor is done for backward compatibility with 1.7 and 1.8. The task for handling the argument collation strength and normalization mode is left to the child class.

Parameters

  collationStrength | collation strength
  decompositionMode |

Deprecated:
  ICU 2.4. Subclasses should use the default constructor instead and handle the strength and normalization mode themselves.

## ◆ Collator() [3/3]

icu::Collator::Collator | ( | const Collator & | other | ) |
| protected

Copy constructor.

Parameters

  other | Collator object to be copied from

Stable:
  ICU 2.0

## Member Function Documentation

## ◆ clone()

virtual Collator * icu::Collator::clone | ( |  | ) | const
| pure virtual

Makes a copy of this object.

Returns
  a copy of this object, owned by the caller

Stable:
  ICU 2.0

Implemented in icu::RuleBasedCollator.

## ◆ compare() [1/7]

virtual EComparisonResult icu::Collator::compare | ( | const char16_t * | source,
|  | int32_t | sourceLength,
|  | const char16_t * | target,
|  | int32_t | targetLength
| ) |  | const
| virtual

The comparison function compares the character data stored in two different string arrays.

Returns information about whether a string array is less than, greater than or equal to another string array.

Example of use:

    .       char16_t ABC[] = {0x41, 0x42, 0x43, 0};  // = "ABC"
    .       char16_t abc[] = {0x61, 0x62, 0x63, 0};  // = "abc"
    .       UErrorCode status = U_ZERO_ERROR;
    .       Collator *myCollation =
    .                         Collator::createInstance(Locale::getUS(), status);
    .       if (U_FAILURE(status)) return;
    .       myCollation->setStrength(Collator::PRIMARY);
    .       // result would be Collator::EQUAL ("abc" == "ABC")
    .       // (no primary difference between "abc" and "ABC")
    .       Collator::EComparisonResult result =
    .                             myCollation->compare(abc, 3, ABC, 3);
    .       myCollation->setStrength(Collator::TERTIARY);
    .       // result would be Collator::LESS ("abc" <<< "ABC")
    .       // (with tertiary difference between "abc" and "ABC")
    .       result = myCollation->compare(abc, 3, ABC, 3);

Parameters

  source | the source string array to be compared with.
  sourceLength | the length of the source string array. If this value is equal to -1, the string array is null-terminated.
  target | the string that is to be compared with the source string.
  targetLength | the length of the target string array. If this value is equal to -1, the string array is null-terminated.

Returns
  Returns a byte value. GREATER if source is greater than target; EQUAL if source is equal to target; LESS if source is less than target

Deprecated:
  ICU 2.6 use the overload with UErrorCode &

Reimplemented in icu::RuleBasedCollator.

## ◆ compare() [2/7]

virtual UCollationResult icu::Collator::compare | ( | const char16_t * | source,
|  | int32_t | sourceLength,
|  | const char16_t * | target,
|  | int32_t | targetLength,
|  | UErrorCode & | status
| ) |  | const
| pure virtual

The comparison function compares the character data stored in two different string arrays.

Returns information about whether a string array is less than, greater than or equal to another string array.

Parameters

  source | the source string array to be compared with.
  sourceLength | the length of the source string array. If this value is equal to -1, the string array is null-terminated.
  target | the string that is to be compared with the source string.
  targetLength | the length of the target string array. If this value is equal to -1, the string array is null-terminated.
  status | possible error code

Returns
  Returns an enum value. UCOL_GREATER if source is greater than target; UCOL_EQUAL if source is equal to target; UCOL_LESS if source is less than target

Stable:
  ICU 2.6

Implemented in icu::RuleBasedCollator, and icu::RuleBasedCollator.

## ◆ compare() [3/7]

virtual EComparisonResult icu::Collator::compare | ( | const UnicodeString & | source,
|  | const UnicodeString & | target
| ) |  | const
| virtual

The comparison function compares the character data stored in two different strings.

Returns information about whether a string is less than, greater than or equal to another string.

Parameters

  source | the source string to be compared with.
  target | the string that is to be compared with the source string.

Returns
  Returns a byte value. GREATER if source is greater than target; EQUAL if source is equal to target; LESS if source is less than target

Deprecated:
  ICU 2.6 use the overload with UErrorCode &

Reimplemented in icu::RuleBasedCollator.

## ◆ compare() [4/7]

virtual EComparisonResult icu::Collator::compare | ( | const UnicodeString & | source,
|  | const UnicodeString & | target,
|  | int32_t | length
| ) |  | const
| virtual

Does the same thing as compare but limits the comparison to a specified length.

Parameters

  source | the source string to be compared with.
  target | the string that is to be compared with the source string.
  length | the length the comparison is limited to

Returns
  Returns a byte value. GREATER if source (up to the specified length) is greater than target; EQUAL if source (up to specified length) is equal to target; LESS if source (up to the specified length) is less than target.

Deprecated:
  ICU 2.6 use the overload with UErrorCode &

Reimplemented in icu::RuleBasedCollator.

## ◆ compare() [5/7]

virtual UCollationResult icu::Collator::compare | ( | const UnicodeString & | source,
|  | const UnicodeString & | target,
|  | int32_t | length,
|  | UErrorCode & | status
| ) |  | const
| pure virtual

Does the same thing as compare but limits the comparison to a specified length.

Parameters

  source | the source string to be compared with.
  target | the string that is to be compared with the source string.
  length | the length the comparison is limited to
  status | possible error code

Returns
  Returns an enum value. UCOL_GREATER if source (up to the specified length) is greater than target; UCOL_EQUAL if source (up to specified length) is equal to target; UCOL_LESS if source (up to the specified length) is less than target.

Stable:
  ICU 2.6

Implemented in icu::RuleBasedCollator, and icu::RuleBasedCollator.

## ◆ compare() [6/7]

virtual UCollationResult icu::Collator::compare | ( | const UnicodeString & | source,
|  | const UnicodeString & | target,
|  | UErrorCode & | status
| ) |  | const
| pure virtual

The comparison function compares the character data stored in two different strings.

Returns information about whether a string is less than, greater than or equal to another string.

Parameters

  source | the source string to be compared with.
  target | the string that is to be compared with the source string.
  status | possible error code

Returns
  Returns an enum value. UCOL_GREATER if source is greater than target; UCOL_EQUAL if source is equal to target; UCOL_LESS if source is less than target

Stable:
  ICU 2.6

Implemented in icu::RuleBasedCollator, and icu::RuleBasedCollator.

## ◆ compare() [7/7]

virtual UCollationResult icu::Collator::compare | ( | UCharIterator & | sIter,
|  | UCharIterator & | tIter,
|  | UErrorCode & | status
| ) |  | const
| virtual

Compares two strings using the Collator.

Returns whether the first one compares less than/equal to/greater than the second one. This version takes UCharIterator input.

Parameters

  sIter | the first ("source") string iterator
  tIter | the second ("target") string iterator
  status | ICU status

Returns
  UCOL_LESS, UCOL_EQUAL or UCOL_GREATER

Stable:
  ICU 4.2

Reimplemented in icu::RuleBasedCollator, and icu::RuleBasedCollator.

## ◆ compareUTF8()

virtual UCollationResult icu::Collator::compareUTF8 | ( | const StringPiece & | source,
|  | const StringPiece & | target,
|  | UErrorCode & | status
| ) |  | const
| virtual

Compares two UTF-8 strings using the Collator.

Returns whether the first one compares less than/equal to/greater than the second one. This version takes UTF-8 input. Note that a StringPiece can be implicitly constructed from a std::string or a NUL-terminated const char * string.

Parameters

  source | the first UTF-8 string
  target | the second UTF-8 string
  status | ICU status

Returns
  UCOL_LESS, UCOL_EQUAL or UCOL_GREATER

Stable:
  ICU 4.2

Reimplemented in icu::RuleBasedCollator.

## ◆ createInstance() [1/2]

static Collator * icu::Collator::createInstance | ( | const Locale & | loc,
|  | UErrorCode & | err
| ) |  |
| static

Gets the collation object for the desired locale.

The resource of the desired locale will be loaded.

Locale::getRoot() is the base collation table and all other languages are built on top of it with additional language-specific modifications.

For some languages, multiple collation types are available; for example, "de@collation=phonebook". Starting with ICU 54, collation attributes can be specified via locale keywords as well, in the old locale extension syntax ("el@colCaseFirst=upper") or in language tag syntax ("el-u-kf-upper"). See User Guide: Collation API.

The UErrorCode& err parameter is used to return status information to the user. To check whether the construction succeeded or not, you should check the value of U_SUCCESS(err). If you wish more detailed information, you can check for informational error results which still indicate success. U_USING_FALLBACK_ERROR indicates that a fall back locale was used. For example, 'de_CH' was requested, but nothing was found there, so 'de' was used. U_USING_DEFAULT_ERROR indicates that the default locale data was used; neither the requested locale nor any of its fall back locales could be found.

The caller owns the returned object and is responsible for deleting it.

Parameters

  loc | The locale ID for which to open a collator.
  err | the error code status.

Returns
  the created table-based collation object based on the desired locale.

See also
  Locale
  ResourceLoader

Stable:
  ICU 2.2

## ◆ createInstance() [2/2]

static Collator * icu::Collator::createInstance | ( | UErrorCode & | err | ) |
| static

Creates the Collator object for the current default locale.

The default locale is determined by Locale::getDefault. The UErrorCode& err parameter is used to return status information to the user. To check whether the construction succeeded or not, you should check the value of U_SUCCESS(err). If you wish more detailed information, you can check for informational error results which still indicate success. U_USING_FALLBACK_ERROR indicates that a fall back locale was used. For example, 'de_CH' was requested, but nothing was found there, so 'de' was used. U_USING_DEFAULT_ERROR indicates that the default locale data was used; neither the requested locale nor any of its fall back locales could be found. The caller owns the returned object and is responsible for deleting it.

Parameters

  err | the error code status.

Returns
  the collation object of the default locale.(for example, en_US)

See also
  Locale::getDefault

Stable:
  ICU 2.0

## ◆ equals()

UBool icu::Collator::equals | ( | const UnicodeString & | source,
|  | const UnicodeString & | target
| ) |  | const

Convenience method for comparing two strings based on the collation rules.

Parameters

  source | the source string to be compared with.
  target | the target string to be compared with.

Returns
  true if the strings are equal according to the collation rules. false, otherwise.

See also
  Collator::compare

Stable:
  ICU 2.0

## ◆ fromUCollator() [1/2]

static const Collator * icu::Collator::fromUCollator | ( | const UCollator * | uc | ) |
| inline static

Internal:
  Do not use. This API is for internal use only.

Definition at line 1188 of file coll.h.

## ◆ fromUCollator() [2/2]

static Collator * icu::Collator::fromUCollator | ( | UCollator * | uc | ) |
| inline static

Internal:
  Do not use. This API is for internal use only.

Definition at line 1184 of file coll.h.

Referenced by icu::RuleBasedCollator::rbcFromUCollator().

## ◆ getAttribute()

virtual UColAttributeValue icu::Collator::getAttribute | ( | UColAttribute | attr,
|  | UErrorCode & | status
| ) |  | const
| pure virtual

Universal attribute getter.

Parameters

  attr | attribute type
  status | to indicate whether the operation went on smoothly or there were errors

Returns
  attribute value

Stable:
  ICU 2.2

Implemented in icu::RuleBasedCollator.

## ◆ getAvailableLocales() [1/2]

static const Locale * icu::Collator::getAvailableLocales | ( | int32_t & | count | ) |
| static

Get the set of Locales for which Collations are installed.

Note this does not include locales supported by registered collators. If collators might have been registered, use the overload of getAvailableLocales that returns a StringEnumeration.

Parameters

  count | the output parameter of number of elements in the locale list

Returns
  the list of available locales for which collations are installed

Stable:
  ICU 2.0

## ◆ getAvailableLocales() [2/2]

static StringEnumeration * icu::Collator::getAvailableLocales | ( | void |  | ) |
| static

Return a StringEnumeration over the locales available at the time of the call, including registered locales.

If a severe error occurs (such as out of memory condition) this will return null. If there is no locale data, an empty enumeration will be returned.

Returns
  a StringEnumeration over the locales available at the time of the call

Stable:
  ICU 2.6

## ◆ getBound()

static int32_t icu::Collator::getBound | ( | const uint8_t * | source,
|  | int32_t | sourceLength,
|  | UColBoundMode | boundType,
|  | uint32_t | noOfLevels,
|  | uint8_t * | result,
|  | int32_t | resultLength,
|  | UErrorCode & | status
| ) |  |
| static

Produce a bound for a given sortkey and a number of levels.

Return value is always the number of bytes needed, regardless of whether the result buffer was big enough or even valid.
Resulting bounds can be used to produce a range of strings that are between upper and lower bounds. For example, if bounds are produced for a sortkey of string "smith", strings between upper and lower bounds with one level would include "Smith", "SMITH", "sMiTh".
There are two upper bounds that can be produced. If UCOL_BOUND_UPPER is produced, strings matched would be as above. However, if bound produced using UCOL_BOUND_UPPER_LONG is used, the above example will also match "Smithsonian" and similar.
For more on usage, see example in cintltst/capitst.c in procedure TestBounds. Sort keys may be compared using `strcmp`.

Parameters

  source | The source sortkey.
  sourceLength | The length of source, or -1 if null-terminated. (If an unmodified sortkey is passed, it is always null terminated).
  boundType | Type of bound required. It can be UCOL_BOUND_LOWER, which produces a lower inclusive bound, UCOL_BOUND_UPPER, that produces upper bound that matches strings of the same length or UCOL_BOUND_UPPER_LONG that matches strings that have the same starting substring as the source string.
  noOfLevels | Number of levels required in the resulting bound (for most uses, the recommended value is 1). See users guide for explanation on number of levels a sortkey can have.
  result | A pointer to a buffer to receive the resulting sortkey.
  resultLength | The maximum size of result.
  status | Used for returning error code if something went wrong. If the number of levels requested is higher than the number of levels in the source key, a warning (U_SORT_KEY_TOO_SHORT_WARNING) is issued.

Returns
  The size needed to fully store the bound.

See also
  ucol_keyHashCode

Stable:
  ICU 2.1

## ◆ getCollationKey() [1/2]

virtual CollationKey & icu::Collator::getCollationKey | ( | const char16_t * | source,
|  | int32_t | sourceLength,
|  | CollationKey & | key,
|  | UErrorCode & | status
| ) |  | const
| pure virtual

Transforms the string into a series of characters that can be compared with CollationKey::compareTo.

It is not possible to restore the original string from the chars in the sort key.

Use CollationKey::equals or CollationKey::compare to compare the generated sort keys.

If the source string is null, a null collation key will be returned.

Note that sort keys are often less efficient than simply doing comparison. For more details, see the ICU User Guide.

Parameters

  source | the source string to be transformed into a sort key.
  sourceLength | length of the collation key
  key | the collation key to be filled in
  status | the error code status.

Returns
  the collation key of the string based on the collation rules.

See also
  CollationKey::compare

Stable:
  ICU 2.0

Implemented in icu::RuleBasedCollator.

## ◆ getCollationKey() [2/2]

virtual CollationKey & icu::Collator::getCollationKey | ( | const UnicodeString & | source,
|  | CollationKey & | key,
|  | UErrorCode & | status
| ) |  | const
| pure virtual

Transforms the string into a series of characters that can be compared with CollationKey::compareTo.

It is not possible to restore the original string from the chars in the sort key.

Use CollationKey::equals or CollationKey::compare to compare the generated sort keys. If the source string is null, a null collation key will be returned.

Note that sort keys are often less efficient than simply doing comparison. For more details, see the ICU User Guide.

Parameters

  source | the source string to be transformed into a sort key.
  key | the collation key to be filled in
  status | the error code status.

Returns
  the collation key of the string based on the collation rules.

See also
  CollationKey::compare

Stable:
  ICU 2.0

Implemented in icu::RuleBasedCollator.

## ◆ getDisplayName() [1/2]

static UnicodeString & icu::Collator::getDisplayName | ( | const Locale & | objectLocale,
|  | const Locale & | displayLocale,
|  | UnicodeString & | name
| ) |  |
| static

Get name of the object for the desired Locale, in the desired language.

Parameters

  objectLocale | must be from getAvailableLocales
  displayLocale | specifies the desired locale for output
  name | the fill-in parameter of the return value

Returns
  display-able name of the object for the object locale in the desired language

Stable:
  ICU 2.0

## ◆ getDisplayName() [2/2]

static UnicodeString & icu::Collator::getDisplayName | ( | const Locale & | objectLocale,
|  | UnicodeString & | name
| ) |  |
| static

Get name of the object for the desired Locale, in the language of the default locale.

Parameters

  objectLocale | must be from getAvailableLocales
  name | the fill-in parameter of the return value

Returns
  name of the object for the desired locale in the default language

Stable:
  ICU 2.0

## ◆ getDynamicClassID()

virtual UClassID icu::Collator::getDynamicClassID | ( | void |  | ) | const
| override pure virtual

Returns a unique class ID POLYMORPHICALLY.

Pure virtual method. This method is to implement a simple version of RTTI, since not all C++ compilers support genuine RTTI. Polymorphic operator==() and clone() methods call this method.

Returns
  The class ID for this object. All objects of a given class have the same class ID. Objects of other classes have different class IDs.

Stable:
  ICU 2.0

Reimplemented from icu::UObject.

Implemented in icu::RuleBasedCollator.

## ◆ getEquivalentReorderCodes()

static int32_t icu::Collator::getEquivalentReorderCodes | ( | int32_t | reorderCode,
|  | int32_t * | dest,
|  | int32_t | destCapacity,
|  | UErrorCode & | status
| ) |  |
| static

Retrieves the reorder codes that are grouped with the given reorder code.

Some reorder codes will be grouped and must reorder together. Beginning with ICU 55, scripts only reorder together if they are primary-equal, for example Hiragana and Katakana.

Parameters

  reorderCode | The reorder code to determine equivalence for.
  dest | The array to fill with the script equivalence reordering codes.
  destCapacity | The length of dest. If it is 0, then dest may be NULL and the function will only return the length of the result without writing any codes (pre-flighting).
  status | A reference to an error code value, which must not indicate a failure before the function call.

Returns
  The length of the of the reordering code equivalence array.

See also
  ucol_setReorderCodes
  Collator::getReorderCodes
  Collator::setReorderCodes
  UScriptCode
  UColReorderCode

Stable:
  ICU 4.8

## ◆ getFunctionalEquivalent()

static Locale icu::Collator::getFunctionalEquivalent | ( | const char * | keyword,
|  | const Locale & | locale,
|  | UBool & | isAvailable,
|  | UErrorCode & | status
| ) |  |
| static

Return the functionally equivalent locale for the given requested locale, with respect to given keyword, for the collation service.

If two locales return the same result, then collators instantiated for these locales will behave equivalently. The converse is not always true; two collators may in fact be equivalent, but return different results, due to internal details. The return result has no other meaning than that stated above, and implies nothing as to the relationship between the two locales. This is intended for use by applications who wish to cache collators, or otherwise reuse collators when possible. The functional equivalent may change over time. For more information, please see the Locales and Services section of the ICU User Guide.

Parameters

  keyword | a particular keyword as enumerated by ucol_getKeywords.
  locale | the requested locale
  isAvailable | reference to a fillin parameter that indicates whether the requested locale was 'available' to the collation service. A locale is defined as 'available' if it physically exists within the collation locale data.
  status | reference to input-output error code

Returns
  the functionally equivalent collation locale, or the root locale upon error.

Stable:
  ICU 3.0

## ◆ getKeywords()

static StringEnumeration * icu::Collator::getKeywords | ( | UErrorCode & | status | ) |
| static

Create a string enumerator of all possible keywords that are relevant to collation.

At this point, the only recognized keyword for this service is "collation".

Parameters

  status | input-output error code

Returns
  a string enumeration over locale strings. The caller is responsible for closing the result.

Stable:
  ICU 3.0

## ◆ getKeywordValues()

static StringEnumeration * icu::Collator::getKeywordValues | ( | const char * | keyword,
|  | UErrorCode & | status
| ) |  |
| static

Given a keyword, create a string enumeration of all values for that keyword that are currently in use.

Parameters

  keyword | a particular keyword as enumerated by ucol_getKeywords. If any other keyword is passed in, status is set to U_ILLEGAL_ARGUMENT_ERROR.
  status | input-output error code

Returns
  a string enumeration over collation keyword values, or NULL upon error. The caller is responsible for deleting the result.

Stable:
  ICU 3.0

## ◆ getKeywordValuesForLocale()

static StringEnumeration * icu::Collator::getKeywordValuesForLocale | ( | const char * | keyword,
|  | const Locale & | locale,
|  | UBool | commonlyUsed,
|  | UErrorCode & | status
| ) |  |
| static

Given a key and a locale, returns an array of string values in a preferred order that would make a difference.

These are all and only those values where the open (creation) of the service with the locale formed from the input locale plus input keyword and that value has different behavior than creation with the input locale alone.

Parameters

  keyword | one of the keys supported by this service. For now, only "collation" is supported.
  locale | the locale
  commonlyUsed | if set to true it will return only commonly used values with the given locale in preferred order. Otherwise, it will return all the available values for the locale.
  status | ICU status

Returns
  a string enumeration over keyword values for the given key and the locale.

Stable:
  ICU 4.2

## ◆ getLocale()

virtual Locale icu::Collator::getLocale | ( | ULocDataLocaleType | type,
|  | UErrorCode & | status
| ) |  | const
| pure virtual

Gets the locale of the Collator.

Parameters

  type | can be either requested, valid or actual locale. For more information see the definition of ULocDataLocaleType in uloc.h
  status | the error code status.

Returns
  locale where the collation data lives. If the collator was instantiated from rules, locale is empty.

Deprecated:
  ICU 2.8 This API is under consideration for revision in ICU 3.0.

Implemented in icu::RuleBasedCollator.

## ◆ getMaxVariable()

virtual UColReorderCode icu::Collator::getMaxVariable | ( |  | ) | const
| virtual

Returns the maximum reordering group whose characters are affected by UCOL_ALTERNATE_HANDLING.

The base class implementation returns UCOL_REORDER_CODE_PUNCTUATION.

Returns
  the maximum variable reordering group.

See also
  setMaxVariable

Stable:
  ICU 53

Reimplemented in icu::RuleBasedCollator.

## ◆ getReorderCodes()

virtual int32_t icu::Collator::getReorderCodes | ( | int32_t * | dest,
|  | int32_t | destCapacity,
|  | UErrorCode & | status
| ) |  | const
| virtual

Retrieves the reordering codes for this collator.

Parameters

  dest | The array to fill with the script ordering.
  destCapacity | The length of dest. If it is 0, then dest may be NULL and the function will only return the length of the result without writing any codes (pre-flighting).
  status | A reference to an error code value, which must not indicate a failure before the function call.

Returns
  The length of the script ordering array.

See also
  ucol_setReorderCodes
  Collator::getEquivalentReorderCodes
  Collator::setReorderCodes
  UScriptCode
  UColReorderCode

Stable:
  ICU 4.8

Reimplemented in icu::RuleBasedCollator.

## ◆ getSortKey() [1/2]

virtual int32_t icu::Collator::getSortKey | ( | const char16_t * | source,
|  | int32_t | sourceLength,
|  | uint8_t * | result,
|  | int32_t | resultLength
| ) |  | const
| pure virtual

Get the sort key as an array of bytes from a char16_t buffer.

Sort key byte arrays are zero-terminated and can be compared using strcmp().

Note that sort keys are often less efficient than simply doing comparison. For more details, see the ICU User Guide.

Parameters

  source | string to be processed.
  sourceLength | length of string to be processed. If -1, the string is 0 terminated and length will be decided by the function.
  result | buffer to store result in. If NULL, number of bytes needed will be returned.
  resultLength | length of the result buffer. If if not enough the buffer will be filled to capacity.

Returns
  Number of bytes needed for storing the sort key

Stable:
  ICU 2.2

Implemented in icu::RuleBasedCollator.

## ◆ getSortKey() [2/2]

virtual int32_t icu::Collator::getSortKey | ( | const UnicodeString & | source,
|  | uint8_t * | result,
|  | int32_t | resultLength
| ) |  | const
| pure virtual

Get the sort key as an array of bytes from a UnicodeString.

Sort key byte arrays are zero-terminated and can be compared using strcmp().

Note that sort keys are often less efficient than simply doing comparison. For more details, see the ICU User Guide.

Parameters

  source | string to be processed.
  result | buffer to store result in. If NULL, number of bytes needed will be returned.
  resultLength | length of the result buffer. If if not enough the buffer will be filled to capacity.

Returns
  Number of bytes needed for storing the sort key

Stable:
  ICU 2.2

Implemented in icu::RuleBasedCollator.

## ◆ getStrength()

virtual ECollationStrength icu::Collator::getStrength | ( | void |  | ) | const
| virtual

Determines the minimum strength that will be used in comparison or transformation.

E.g. with strength == SECONDARY, the tertiary difference is ignored

E.g. with strength == PRIMARY, the secondary and tertiary difference are ignored.

Returns
  the current comparison level.

See also
  Collator::setStrength

Deprecated:
  ICU 2.6 Use getAttribute(UCOL_STRENGTH...) instead

## ◆ getTailoredSet()

virtual UnicodeSet * icu::Collator::getTailoredSet | ( | UErrorCode & | status | ) | const
| virtual

Get a UnicodeSet that contains all the characters and sequences tailored in this collator.

Parameters

  status | error code of the operation

Returns
  a pointer to a UnicodeSet object containing all the code points and sequences that may sort differently than in the root collator. The object must be disposed of by using delete

Stable:
  ICU 2.4

Reimplemented in icu::RuleBasedCollator.

## ◆ getVariableTop()

virtual uint32_t icu::Collator::getVariableTop | ( | UErrorCode & | status | ) | const
| pure virtual

Gets the variable top value of a Collator.

Parameters

  status | error code (not changed by function). If error code is set, the return value is undefined.

Returns
  the variable top primary weight

See also
  getMaxVariable

Stable:
  ICU 2.0

Implemented in icu::RuleBasedCollator.

## ◆ getVersion()

virtual void icu::Collator::getVersion | ( | UVersionInfo | info | ) | const
| pure virtual

Gets the version information for a Collator.

Parameters

  info | the version # information, the result will be filled in

Stable:
  ICU 2.0

Implemented in icu::RuleBasedCollator.

## ◆ greater()

UBool icu::Collator::greater | ( | const UnicodeString & | source,
|  | const UnicodeString & | target
| ) |  | const

Convenience method for comparing two strings based on the collation rules.

Parameters

  source | the source string to be compared with.
  target | the target string to be compared with.

Returns
  true if the first string is greater than the second one, according to the collation rules. false, otherwise.

See also
  Collator::compare

Stable:
  ICU 2.0

## ◆ greaterOrEqual()

UBool icu::Collator::greaterOrEqual | ( | const UnicodeString & | source,
|  | const UnicodeString & | target
| ) |  | const

Convenience method for comparing two strings based on the collation rules.

Parameters

  source | the source string to be compared with.
  target | the target string to be compared with.

Returns
  true if the first string is greater than or equal to the second one, according to the collation rules. false, otherwise.

See also
  Collator::compare

Stable:
  ICU 2.0

## ◆ hashCode()

virtual int32_t icu::Collator::hashCode | ( | void |  | ) | const
| pure virtual

Generates the hash code for the collation object.

Stable:
  ICU 2.0

Implemented in icu::RuleBasedCollator.

## ◆ internalCompareUTF8()

virtual UCollationResult icu::Collator::internalCompareUTF8 | ( | const char * | left,
|  | int32_t | leftLength,
|  | const char * | right,
|  | int32_t | rightLength,
|  | UErrorCode & | errorCode
| ) |  | const
| virtual

Implements ucol_strcollUTF8().

Internal:
  Do not use. This API is for internal use only.

Reimplemented in icu::RuleBasedCollator.

## ◆ internalGetShortDefinitionString()

virtual int32_t icu::Collator::internalGetShortDefinitionString | ( | const char * | locale,
|  | char * | buffer,
|  | int32_t | capacity,
|  | UErrorCode & | status
| ) |  | const
| virtual

Get the short definition string for a collator.

This internal API harvests the collator's locale and the attribute set and produces a string that can be used for opening a collator with the same attributes using the ucol_openFromShortString API. This string will be normalized. The structure and the syntax of the string is defined in the "Naming collators" section of the users guide: https://unicode-org.github.io/icu/userguide/collation/concepts#collator-naming-scheme This function supports preflighting.

This is internal, and intended to be used with delegate converters.

Parameters

  locale | a locale that will appear as a collators locale in the resulting short string definition. If NULL, the locale will be harvested from the collator.
  buffer | space to hold the resulting string
  capacity | capacity of the buffer
  status | for returning errors. All the preflighting errors are featured

Returns
  length of the resulting string

See also
  ucol_openFromShortString
  ucol_normalizeShortDefinitionString
  ucol_getShortDefinitionString

Internal:
  Do not use. This API is for internal use only.

Reimplemented in icu::RuleBasedCollator.

## ◆ internalNextSortKeyPart()

virtual int32_t icu::Collator::internalNextSortKeyPart | ( | UCharIterator * | iter,
|  | uint32_t | state[2],
|  | uint8_t * | dest,
|  | int32_t | count,
|  | UErrorCode & | errorCode
| ) |  | const
| virtual

Implements ucol_nextSortKeyPart().

Internal:
  Do not use. This API is for internal use only.

Reimplemented in icu::RuleBasedCollator.

## ◆ operator!=()

virtual bool icu::Collator::operator!= | ( | const Collator & | other | ) | const
| virtual

Returns true if "other" is not the same as "this".

Calls ! operator==(const Collator&) const which works for all subclasses.

Parameters

  other | Collator object to be compared

Returns
  true if other is not the same as this.

Stable:
  ICU 2.0

## ◆ operator==()

virtual bool icu::Collator::operator== | ( | const Collator & | other | ) | const
| virtual

Returns true if "other" is the same as "this".

The base class implementation returns true if "other" has the same type/class as "this": `typeid(*this) == typeid(other)`.

Subclass implementations should do something like the following:

    if (this == &other) { return true; }
    if (!Collator::operator==(other)) { return false; }  // not the same class

    const MyCollator &o = (const MyCollator&)other;
    (compare this vs. o's subclass fields)

Parameters

  other | Collator object to be compared

Returns
  true if other is the same as this.

Stable:
  ICU 2.0

Reimplemented in icu::RuleBasedCollator.

## ◆ registerFactory()

static URegistryKey icu::Collator::registerFactory | ( | CollatorFactory * | toAdopt,
|  | UErrorCode & | status
| ) |  |
| static

Register a new CollatorFactory.

The factory will be adopted. Because ICU may choose to cache collators internally, this must be called at application startup, prior to any calls to Collator::createInstance to avoid undefined behavior.

Parameters

  toAdopt | the CollatorFactory instance to be adopted
  status | the in/out status code, no special meanings are assigned

Returns
  a registry key that can be used to unregister this collator

Stable:
  ICU 2.6

## ◆ registerInstance()

static URegistryKey icu::Collator::registerInstance | ( | Collator * | toAdopt,
|  | const Locale & | locale,
|  | UErrorCode & | status
| ) |  |
| static

Register a new Collator.

The collator will be adopted. Because ICU may choose to cache collators internally, this must be called at application startup, prior to any calls to Collator::createInstance to avoid undefined behavior.

Parameters

  toAdopt | the Collator instance to be adopted
  locale | the locale with which the collator will be associated
  status | the in/out status code, no special meanings are assigned

Returns
  a registry key that can be used to unregister this collator

Stable:
  ICU 2.6

## ◆ safeClone()

virtual Collator * icu::Collator::safeClone | ( |  | ) | const
| virtual

Same as clone().

The base class implementation simply calls clone().

Returns
  a copy of this object, owned by the caller

See also
  clone()

Deprecated:
  ICU 50 no need to have two methods for cloning

## ◆ setAttribute()

virtual void icu::Collator::setAttribute | ( | UColAttribute | attr,
|  | UColAttributeValue | value,
|  | UErrorCode & | status
| ) |  |
| pure virtual

Universal attribute setter.

Parameters

  attr | attribute type
  value | attribute value
  status | to indicate whether the operation went on smoothly or there were errors

Stable:
  ICU 2.2

Implemented in icu::RuleBasedCollator.

## ◆ setLocales()

virtual void icu::Collator::setLocales | ( | const Locale & | requestedLocale,
|  | const Locale & | validLocale,
|  | const Locale & | actualLocale
| ) |  |
| virtual

Used internally by registration to define the requested and valid locales.

Parameters

  requestedLocale | the requested locale
  validLocale | the valid locale
  actualLocale | the actual locale

Internal:
  Do not use. This API is for internal use only.

Reimplemented in icu::RuleBasedCollator.

## ◆ setMaxVariable()

virtual Collator & icu::Collator::setMaxVariable | ( | UColReorderCode | group,
|  | UErrorCode & | errorCode
| ) |  |
| virtual

Sets the variable top to the top of the specified reordering group.

The variable top determines the highest-sorting character which is affected by UCOL_ALTERNATE_HANDLING. If that attribute is set to UCOL_NON_IGNORABLE, then the variable top has no effect.

The base class implementation sets U_UNSUPPORTED_ERROR.

Parameters

  group | one of UCOL_REORDER_CODE_SPACE, UCOL_REORDER_CODE_PUNCTUATION, UCOL_REORDER_CODE_SYMBOL, UCOL_REORDER_CODE_CURRENCY; or UCOL_REORDER_CODE_DEFAULT to restore the default max variable group
  errorCode | Standard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)

Returns
  *this

See also
  getMaxVariable

Stable:
  ICU 53

Reimplemented in icu::RuleBasedCollator.

## ◆ setReorderCodes()

virtual void icu::Collator::setReorderCodes | ( | const int32_t * | reorderCodes,
|  | int32_t | reorderCodesLength,
|  | UErrorCode & | status
| ) |  |
| virtual

Sets the ordering of scripts for this collator.

The reordering codes are a combination of script codes and reorder codes.

Parameters

  reorderCodes | An array of script codes in the new order. This can be NULL if the length is also set to 0. An empty array will clear any reordering codes on the collator.
  reorderCodesLength | The length of reorderCodes.
  status | error code

See also
  ucol_setReorderCodes
  Collator::getReorderCodes
  Collator::getEquivalentReorderCodes
  UScriptCode
  UColReorderCode

Stable:
  ICU 4.8

Reimplemented in icu::RuleBasedCollator.

## ◆ setStrength()

virtual void icu::Collator::setStrength | ( | ECollationStrength | newStrength | ) |
| virtual

Sets the minimum strength to be used in comparison or transformation.

Example of use:

     UErrorCode status = U_ZERO_ERROR;
    Collator*myCollation = Collator::createInstance(Locale::getUS(), status);
    if (U_FAILURE(status)) return;
    myCollation->setStrength(Collator::PRIMARY);
    // result will be "abc" == "ABC"
    // tertiary differences will be ignored
    Collator::ComparisonResult result = myCollation->compare("abc", "ABC");
    U_FAILURE#define U_FAILURE(x)Does the error code indicate a failure?Definition: utypes.h:717

See also
  Collator::getStrength

Parameters

  newStrength | the new comparison level.

Deprecated:
  ICU 2.6 Use setAttribute(UCOL_STRENGTH...) instead

## ◆ setVariableTop() [1/3]

virtual uint32_t icu::Collator::setVariableTop | ( | const char16_t * | varTop,
|  | int32_t | len,
|  | UErrorCode & | status
| ) |  |
| pure virtual

Sets the variable top to the primary weight of the specified string.

Beginning with ICU 53, the variable top is pinned to the top of one of the supported reordering groups, and it must not be beyond the last of those groups. See setMaxVariable().

Parameters

  varTop | one or more (if contraction) char16_ts to which the variable top should be set
  len | length of variable top string. If -1 it is considered to be zero terminated.
  status | error code. If error code is set, the return value is undefined. Errors set by this function are: U_CE_NOT_FOUND_ERROR if more than one character was passed and there is no such contraction U_ILLEGAL_ARGUMENT_ERROR if the variable top is beyond the last reordering group supported by setMaxVariable()

Returns
  variable top primary weight

Deprecated:
  ICU 53 Call setMaxVariable() instead.

Implemented in icu::RuleBasedCollator.

## ◆ setVariableTop() [2/3]

virtual uint32_t icu::Collator::setVariableTop | ( | const UnicodeString & | varTop,
|  | UErrorCode & | status
| ) |  |
| pure virtual

Sets the variable top to the primary weight of the specified string.

Beginning with ICU 53, the variable top is pinned to the top of one of the supported reordering groups, and it must not be beyond the last of those groups. See setMaxVariable().

Parameters

  varTop | a UnicodeString size 1 or more (if contraction) of char16_ts to which the variable top should be set
  status | error code. If error code is set, the return value is undefined. Errors set by this function are: U_CE_NOT_FOUND_ERROR if more than one character was passed and there is no such contraction U_ILLEGAL_ARGUMENT_ERROR if the variable top is beyond the last reordering group supported by setMaxVariable()

Returns
  variable top primary weight

Deprecated:
  ICU 53 Call setMaxVariable() instead.

Implemented in icu::RuleBasedCollator.

## ◆ setVariableTop() [3/3]

virtual void icu::Collator::setVariableTop | ( | uint32_t | varTop,
|  | UErrorCode & | status
| ) |  |
| pure virtual

Sets the variable top to the specified primary weight.

Beginning with ICU 53, the variable top is pinned to the top of one of the supported reordering groups, and it must not be beyond the last of those groups. See setMaxVariable().

Parameters

  varTop | primary weight, as returned by setVariableTop or ucol_getVariableTop
  status | error code

Deprecated:
  ICU 53 Call setMaxVariable() instead.

Implemented in icu::RuleBasedCollator.

## ◆ toUCollator() [1/2]

UCollator * icu::Collator::toUCollator | ( |  | ) |
| inline

Internal:
  Do not use. This API is for internal use only.

Definition at line 1192 of file coll.h.

## ◆ toUCollator() [2/2]

const UCollator * icu::Collator::toUCollator | ( |  | ) | const
| inline

Internal:
  Do not use. This API is for internal use only.

Definition at line 1196 of file coll.h.

## ◆ unregister()

static UBool icu::Collator::unregister | ( | URegistryKey | key,
|  | UErrorCode & | status
| ) |  |
| static

Unregister a previously-registered Collator or CollatorFactory using the key returned from the register call.

Key becomes invalid after a successful call and should not be used again. The object corresponding to the key will be deleted. Because ICU may choose to cache collators internally, this should be called during application shutdown, after all calls to Collator::createInstance to avoid undefined behavior.

Parameters

  key | the registry key returned by a previous call to registerInstance
  status | the in/out status code, no special meanings are assigned

Returns
  true if the collator for the key was successfully unregistered

Stable:
  ICU 2.6

## Friends And Related Function Documentation

## ◆ CFactory

friend class CFactory
| friend

Definition at line 1207 of file coll.h.

## ◆ ICUCollatorFactory

friend class ICUCollatorFactory
| friend

Definition at line 1209 of file coll.h.

## ◆ ICUCollatorService

friend class ICUCollatorService
| friend

Definition at line 1210 of file coll.h.

## ◆ SimpleCFactory

friend class SimpleCFactory
| friend

Definition at line 1208 of file coll.h.

The documentation for this class was generated from the following file:

- coll.h