CollationElementIterator JDK 1.6)

Description

publicfinal class CollationElementIterator

The CollationElementIterator class is used as an iterator to walk through each character of an international string.

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.

See also: Collator RuleBasedCollator

Methods

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public int getMaxExpansion (int order)

Return the maximum length of any expansion sequences that end with the specified comparison order.

public int getOffset ()

Returns the character offset in the original text corresponding to the next collation element.

pack-privatefinalstatic boolean isIgnorable (int order)

Check if a comparison order is ignorable.

public int next ()

Get the next collation element in the string.

public int previous ()

Get the previous collation element in the string.

publicfinalstatic int primaryOrder (int order)

Return the primary component of a collation element.

public void reset ()

Resets the cursor to the beginning of the string.

publicfinalstatic short secondaryOrder (int order)

Return the secondary component of a collation element.

public void setOffset (int newOffset)

Sets the iterator to point to the collation element corresponding to the specified character (the parameter is a CHARACTER offset in the original string, not an offset into its corresponding sequence of collation elements).

public void setText (CharacterIterator source)

Set a new string over which to iterate.

public void setText (String source)

Set a new string over which to iterate.

pack-privatefinal int strengthOrder (int order)

Get the comparison order in the desired strength.

publicfinalstatic short tertiaryOrder (int order)

Return the tertiary component of a collation element.