java.text
Class CollationElementIterator

java.lang.Object
  java.text.CollationElementIterator

public final class CollationElementIterator
extends Object

CollationElementIterator is created by a RuleBasedCollator to iterate through a string. The return result of each iteration is a 32-bit collation element that defines the ordering priority of the next character or sequence of characters in the source string.

For illustration, consider the following in Spanish:

"ca" -> the first collation element is collation_element('c') and second collation element is collation_element('a').

Since "ch" in Spanish sorts as one entity, the below example returns one collation element for the two characters 'c' and 'h'

"cha" -> the first collation element is collation_element('ch') and second collation element is collation_element('a').

And in German,

Since the character '\u0086' is a composed character of 'a' and 'e', the iterator returns two collation elements for the single character '\u0086'

"\u0086b" -> the first collation element is collation_element('a'), the second collation element is collation_element('e'), and the third collation element is collation_element('b').

Field Summary

static int

NULLORDER This constant is returned by the iterator in the methods next() and previous() when the end or the beginning of the source string has been reached, and there are no more valid collation elements to return.

Constructor Summary

CollationElementIterator(com.ibm.icu4jni.text.CollationElementIterator iterator)

Method Summary

int	getMaxExpansion(int order) Obtains the maximum length of any expansion sequence that ends with the specified collation element.
int	getOffset() Obtains the character offset in the source string corresponding to the next collation element.
int	next() Obtains the next collation element in the source string.
int	previous() Obtains the previous collation element in the source string.
static int	primaryOrder(int order) Obtains the primary order of the specified collation element, i.e.
void	reset() Repositions the cursor to point at the first element of the current string.
static short	secondaryOrder(int order) Obtains the secondary order of the specified collation element, i.e.
void	setOffset(int newOffset) Points the iterator at the collation element associated with the character in the source string which is found at the supplied offset.
void	setText(CharacterIterator source) Sets a new source string iterator for iteration, and reset the offset to the beginning of the text.
void	setText(String source) Sets a new source string for iteration, and reset the offset to the beginning of the text.
static short	tertiaryOrder(int order) Obtains the tertiary order of the specified collation element, i.e.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

NULLORDER

public static final int NULLORDER

This constant is returned by the iterator in the methods next() and previous() when the end or the beginning of the source string has been reached, and there are no more valid collation elements to return.

See Also:

Constant Field Values

Constructor Detail

CollationElementIterator

CollationElementIterator(com.ibm.icu4jni.text.CollationElementIterator iterator)

Method Detail

getMaxExpansion

public int getMaxExpansion(int order)

Obtains the maximum length of any expansion sequence that ends with the specified collation element. If there is no expansion with this collation element as the last element, returns 1.

Parameters:

order - a collation element that has been previously obtained from a call to either the next() or previous() method.

Returns:

the maximum length of any expansion sequence ending with the specified collation element.

getOffset

public int getOffset()

Obtains the character offset in the source string corresponding to the next collation element. This value could be any of:

The index of the first character in the source string that matches the value of the next collation element. (This means that if setOffset(offset) sets the index in the middle of a contraction, getOffset() returns the index of the first character in the contraction, which may not be equal to the original offset that was set. Hence calling getOffset() immediately after setOffset(offset) does not guarantee that the original offset set will be returned.)

If normalization is on, the index of the immediate subsequent character, or composite character with the first character, having a combining class of 0.

The length of the source string, if iteration has reached the end.

Returns:

The position of the collation element in the source string that will be returned in the next invocation of the next() method.

next

public int next()

Obtains the next collation element in the source string.

Returns:

the next collation element or NULLORDER if the end of the iteration has been reached.

previous

public int previous()

Obtains the previous collation element in the source string.

Returns:

the previous collation element, or NULLORDER when the start of the iteration has been reached.

primaryOrder

public static final int primaryOrder(int order)

Obtains the primary order of the specified collation element, i.e. the first 16 bits. This value is unsigned.

Parameters:

order -

Returns:

the element's 16 bits primary order.

reset

public void reset()

Repositions the cursor to point at the first element of the current string. The next call to next() or previous() will return the first and last collation element in the string, respectively.

If the RuleBasedCollator used by this iterator has had its attributes changed, calling reset() will reinitialize the iterator to use the new attributes.

secondaryOrder

public static final short secondaryOrder(int order)

Obtains the secondary order of the specified collation element, i.e. the 16th to 23th bits, inclusive. This value is unsigned.

Parameters:

order -

Returns:

the 8 bit secondary order of the element

setOffset

public void setOffset(int newOffset)

Points the iterator at the collation element associated with the character in the source string which is found at the supplied offset. After this call completes, an invocation of the next() method will return this collation element.

If newOffset corresponds to a character which is part of a sequence that maps to a single collation element the iterator is adjusted to the start of that sequence. As a result of this, any subsequent call made to getOffset() may not return the same value set by this method.

If the decomposition mode is on, and offset is in the middle of a decomposable range of source text, the iterator may not return a correct result for the next forwards or backwards iteration. The user must ensure that the offset is not in the middle of a decomposable range.

Parameters:

newOffset - the character offset into the original source string to set. Note that this is not an offset into the corresponding sequence of collation elements.

setText

public void setText(CharacterIterator source)

Sets a new source string iterator for iteration, and reset the offset to the beginning of the text.

Parameters:

source - the new source string iterator for iteration.

setText

public void setText(String source)

Sets a new source string for iteration, and reset the offset to the beginning of the text.

Parameters:

source - the new source string for iteration

tertiaryOrder

public static final short tertiaryOrder(int order)

Obtains the tertiary order of the specified collation element, i.e. the last 8 bits. This value is unsigned.

Parameters:

order -

Returns:

the 8 bits tertiary order of the element