public abstract class Collator extends Object implements Comparator<Object>, Cloneable
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("�?", "a??") != 0) { System.out.println("�? is not equal to a?? without decomposition"); myCollator.setDecomposition(Collator.CANONICAL_DECOMPOSITION); if (myCollator.compare("�?", "a??") != 0) { System.out.println("Error: �? should be equal to a?? with decomposition"); } else { System.out.println("�? is equal to a?? with decomposition"); } } else { System.out.println("Error: �? should be not equal to a?? without decomposition"); }
RuleBasedCollator
,
CollationKey
Modifier and Type | Field and Description |
---|---|
static int |
CANONICAL_DECOMPOSITION
Constant used to specify the decomposition rule.
|
static int |
FULL_DECOMPOSITION
Constant used to specify the decomposition rule.
|
static int |
IDENTICAL
Constant used to specify the collation strength.
|
static int |
NO_DECOMPOSITION
Constant used to specify the decomposition rule.
|
static int |
PRIMARY
Constant used to specify the collation strength.
|
static int |
SECONDARY
Constant used to specify the collation strength.
|
static int |
TERTIARY
Constant used to specify the collation strength.
|
Modifier | Constructor and Description |
---|---|
protected |
Collator()
Constructs a new
Collator instance. |
Modifier and Type | Method and Description |
---|---|
Object |
clone()
Returns a new collator with the same decomposition mode and
strength value as this collator.
|
int |
compare(Object object1,
Object object2)
Compares two objects to determine their relative order.
|
abstract int |
compare(String string1,
String string2)
Compares two strings to determine their relative order.
|
boolean |
equals(Object object)
Compares this collator with the specified object and indicates if they
are equal.
|
boolean |
equals(String string1,
String string2)
Compares two strings using the collation rules to determine if they are
equal.
|
static Locale[] |
getAvailableLocales()
Returns an array of locales for which custom
Collator instances
are available. |
abstract CollationKey |
getCollationKey(String string)
Returns a
CollationKey for the specified string for this collator
with the current decomposition rule and strength value. |
int |
getDecomposition()
Returns the decomposition rule for this collator.
|
static Collator |
getInstance()
Returns a
Collator instance which is appropriate for the user's default
Locale . |
static Collator |
getInstance(Locale locale)
Returns a
Collator instance which is appropriate for locale . |
int |
getStrength()
Returns the strength value for this collator.
|
abstract int |
hashCode()
Returns an integer hash code for this object.
|
void |
setDecomposition(int value)
Sets the decomposition rule for this collator.
|
void |
setStrength(int value)
Sets the strength value for this collator.
|
public static final int NO_DECOMPOSITION
public static final int CANONICAL_DECOMPOSITION
public static final int FULL_DECOMPOSITION
public static final int PRIMARY
public static final int SECONDARY
public static final int TERTIARY
public static final int IDENTICAL
public Object clone()
public int compare(Object object1, Object object2)
compare
in interface Comparator<Object>
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
.public abstract int compare(String string1, String string2)
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
.public boolean equals(Object object)
equals
in interface Comparator<Object>
equals
in class Object
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.hashCode()
public boolean equals(String string1, String string2)
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.public static Locale[] getAvailableLocales()
Collator
instances
are available.
Note that Android does not support user-supplied locale service providers.
public abstract CollationKey getCollationKey(String string)
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
.public int getDecomposition()
NO_DECOMPOSITION
or
CANONICAL_DECOMPOSITION
. FULL_DECOMPOSITION
is
not supported.public static Collator getInstance()
Collator
instance which is appropriate for the user's default
Locale
.
See "Be wary of the default locale".public static Collator getInstance(Locale locale)
Collator
instance which is appropriate for locale
.public int getStrength()
public abstract int hashCode()
Object
Object.equals(java.lang.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.
hashCode
in class Object
Object.equals(java.lang.Object)
public void setDecomposition(int value)
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
.public void setStrength(int value)
value
- the strength value, either PRIMARY, SECONDARY, TERTIARY, or
IDENTICAL.IllegalArgumentException
- if the provided strength value is not valid.