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Class java.text.CollationElementIterator

java.lang.Object
   |
   +----java.text.CollationElementIterator

public final class CollationElementIterator
extends Object

The CollationElementIterator class is used as an iterator to walk through each character of an international string. Use the iterator to return the ordering priority of the positioned character. The ordering priority of a character, which we refer to as a key, defines how a character is collated in the given collation object.

For example, consider the following in Spanish:

 "ca" -> the first key is key('c') and second key is key('a').
 "cha" -> the first key is key('ch') and second key is key('a').

And in German,

 "дb"-> the first key is key('a'), the second key is key('e'), and
 the third key is key('b').

The key of a character is an integer composed of primary order(short), secondary order(byte), and tertiary order(byte). Java strictly defines the size and signedness of its primitive data types. Therefore, the static functions primaryOrder, secondaryOrder, and tertiaryOrder return int, short, and short respectively to ensure the correctness of the key value.

Example of the iterator usage,

 // get the first key of the string
 String str = "This is a test";
 CollationElementIterator c =
     new CollationElementIterator(str, 0, str.length(),
                                  Collator.getInstance());
 int primaryOrder = CollationElementIterator.primaryOrder(c->next());

CollationElementIterator.next returns the collation order of the next character. A collation order consists of primary order, secondary order and tertiary order. The data type of the collation order is int. The first 16 bits of a collation order is its primary order; the next 8 bits is the secondary order and the last 8 bits is the tertiary order.

See Also:: Collator, RuleBasedCollator

NULLORDER: Null order which indicates the end of string is reached by the cursor.

next(): Get the ordering priority of the next character in the string.
primaryOrder(int): Get the primary order of a collation order.
reset(): Resets the cursor to the beginning of the string.
secondaryOrder(int): Get the secondary order of a collation order.
tertiaryOrder(int): Get the tertiary order of a collation order.

NULLORDER

 public static final int NULLORDER

Null order which indicates the end of string is reached by the cursor.

reset

 public void reset()

Resets the cursor to the beginning of the string.

next

 public int next()

Get the ordering priority of the next character in the string.

Returns:: the next character's ordering. Returns NULLORDER if the end of string is reached.

primaryOrder

 public static final int primaryOrder(int order)

Get the primary order of a collation order.

Parameters:: order - the collation order
Returns:: the primary order of a collation order.

secondaryOrder

 public static final short secondaryOrder(int order)

Get the secondary order of a collation order.

Parameters:: order - the collation order
Returns:: the secondary order of a collation order.

tertiaryOrder

 public static final short tertiaryOrder(int order)

Get the tertiary order of a collation order.

Parameters:: order - the collation order
Returns:: the tertiary order of a collation order.

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