java.lang.Object | |
↳ | java.text.Collator |
Known Direct Subclasses |
Performs locale-sensitive string comparison. A concrete subclass,
RuleBasedCollator
, allows customization of the collation ordering by
the use of rule sets.
Following the Unicode Consortium's specifications for the Unicode Collation Algorithm (UCA), there are 4 different levels of strength used in comparisons:
This Collator
deals only with two decomposition modes, the canonical
decomposition mode and one that does not use any decomposition. The
compatibility decomposition mode
java.text.Collator.FULL_DECOMPOSITION
is not supported here. If the
canonical decomposition mode is set, Collator
handles un-normalized
text properly, producing the same results as if the text were normalized in
NFD. If canonical decomposition is turned off, it is the user's
responsibility to ensure that all text is already in the appropriate form
before performing a comparison or before getting a CollationKey
.
Examples:
// Get the Collator for US English and set its strength to PRIMARY Collator usCollator = Collator.getInstance(Locale.US); usCollator.setStrength(Collator.PRIMARY); if (usCollator.compare("abc", "ABC") == 0) { System.out.println("Strings are equivalent"); }
The following example shows how to compare two strings using the collator for the default locale.
// Compare two strings in the default locale Collator myCollator = Collator.getInstance(); myCollator.setDecomposition(Collator.NO_DECOMPOSITION); if (myCollator.compare("ḁ̀", "ḁ̀") != 0) { System.out.println("ḁ̀ is not equal to ḁ̀ without decomposition"); myCollator.setDecomposition(Collator.CANONICAL_DECOMPOSITION); if (myCollator.compare("ḁ̀", "ḁ̀") != 0) { System.out.println("Error: ḁ̀ should be equal to ḁ̀ with decomposition"); } else { System.out.println("ḁ̀ is equal to ḁ̀ with decomposition"); } } else { System.out.println("Error: ḁ̀ should be not equal to ḁ̀ without decomposition"); }
Constants | |||||||||||
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int | CANONICAL_DECOMPOSITION | Constant used to specify the decomposition rule. | |||||||||
int | FULL_DECOMPOSITION | Constant used to specify the decomposition rule. | |||||||||
int | IDENTICAL | Constant used to specify the collation strength. | |||||||||
int | NO_DECOMPOSITION | Constant used to specify the decomposition rule. | |||||||||
int | PRIMARY | Constant used to specify the collation strength. | |||||||||
int | SECONDARY | Constant used to specify the collation strength. | |||||||||
int | TERTIARY | Constant used to specify the collation strength. |
Protected Constructors | |||||||||||
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Constructs a new
Collator instance. |
Public Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Returns a new collator with the same decomposition mode and
strength value as this collator.
| |||||||||||
Compares two strings to determine their relative order.
| |||||||||||
Compares two objects to determine their relative order.
| |||||||||||
Compares this collator with the specified object and indicates if they
are equal.
| |||||||||||
Compares two strings using the collation rules to determine if they are
equal.
| |||||||||||
Returns an array of locales for which custom
Collator instances
are available. | |||||||||||
Returns a
CollationKey for the specified string for this collator
with the current decomposition rule and strength value. | |||||||||||
Returns the decomposition rule for this collator.
| |||||||||||
Returns a
Collator instance which is appropriate for the user's default
Locale . | |||||||||||
Returns a
Collator instance which is appropriate for locale . | |||||||||||
Returns the strength value for this collator.
| |||||||||||
Returns an integer hash code for this object.
| |||||||||||
Sets the decomposition rule for this collator.
| |||||||||||
Sets the strength value for this collator.
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[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
| |||||||||||
From interface
java.util.Comparator
|
Constant used to specify the decomposition rule.
Constant used to specify the decomposition rule. This value for decomposition is not supported.
Constant used to specify the collation strength.
Constant used to specify the decomposition rule.
Constant used to specify the collation strength.
Constant used to specify the collation strength.
Constant used to specify the collation strength.
Returns a new collator with the same decomposition mode and strength value as this collator.
Compares two strings to determine their relative order.
string1 | the first string to compare. |
---|---|
string2 | the second string to compare. |
string1
is less than string2
,
0 if they are equal and a positive value if string1
is
greater than string2
.
Compares two objects to determine their relative order. The objects must be strings.
object1 | the first string to compare. |
---|---|
object2 | the second string to compare. |
object1
is less than object2
,
0 if they are equal, and a positive value if object1
is
greater than object2
.ClassCastException | if object1 or object2 is not a String .
|
---|
Compares this collator with the specified object and indicates if they are equal.
object | the object to compare with this object. |
---|
true
if object
is a Collator
object and
it has the same strength and decomposition values as this
collator; false
otherwise.Compares two strings using the collation rules to determine if they are equal.
string1 | the first string to compare. |
---|---|
string2 | the second string to compare. |
true
if string1
and string2
are equal
using the collation rules, false otherwise.
Returns an array of locales for which custom Collator
instances
are available.
Note that Android does not support user-supplied locale service providers.
Returns a CollationKey
for the specified string for this collator
with the current decomposition rule and strength value.
string | the source string that is converted into a collation key. |
---|
string
.
Returns the decomposition rule for this collator.
NO_DECOMPOSITION
or
CANONICAL_DECOMPOSITION
. FULL_DECOMPOSITION
is
not supported.
Returns a Collator
instance which is appropriate for the user's default
Locale
.
See "Be wary of the default locale".
Returns a Collator
instance which is appropriate for locale
.
Returns the strength value for this collator.
Returns an integer hash code for this object. By contract, any two
objects for which equals(Object)
returns true
must return
the same hash code value. This means that subclasses of Object
usually override both methods or neither method.
Note that hash values must not change over time unless information used in equals comparisons also changes.
See Writing a correct
hashCode
method
if you intend implementing your own hashCode
method.
Sets the decomposition rule for this collator.
value | the decomposition rule, either NO_DECOMPOSITION or
CANONICAL_DECOMPOSITION . FULL_DECOMPOSITION
is not supported. |
---|
IllegalArgumentException | if the provided decomposition rule is not valid. This includes
FULL_DECOMPOSITION .
|
---|
Sets the strength value for this collator.
value | the strength value, either PRIMARY, SECONDARY, TERTIARY, or IDENTICAL. |
---|
IllegalArgumentException | if the provided strength value is not valid. |
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