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,
"äb"-> 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,
String testString = "This is a test";
RuleBasedCollator ruleBasedCollator = (RuleBasedCollator)Collator.getInstance();
CollationElementIterator collationElementIterator = ruleBasedCollator.getCollationElementIterator(testString);
int primaryOrder = CollationElementIterator.primaryOrder(collationElementIterator.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.