com.ibm.icu.text

Class UCharacterIterator

java.lang.Object

com.ibm.icu.text.UCharacterIterator

All Implemented Interfaces:

UForwardCharacterIterator, Cloneable

public abstract class UCharacterIterator
extends Object
implements Cloneable, UForwardCharacterIterator

Abstract class that defines an API for iteration on text objects.This is an interface for forward and backward iteration and random access into a text object. Forward iteration is done with post-increment and backward iteration is done with pre-decrement semantics, while the java.text.CharacterIterator interface methods provided forward iteration with "pre-increment" and backward iteration with pre-decrement semantics. This API is more efficient for forward iteration over code points. The other major difference is that this API can do both code unit and code point iteration, java.text.CharacterIterator can only iterate over code units and is limited to BMP (0 - 0xFFFF)

Author:

Ram

Status:

Stable ICU 2.4.

Field Summary

Fields inherited from interface com.ibm.icu.text.UForwardCharacterIterator

DONE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	UCharacterIterator() Protected default constructor for the subclasses

Method Summary

Modifier and Type	Method and Description
Object	clone() Creates a copy of this iterator, independent from other iterators.
abstract int	current() Returns the code unit at the current index.
int	currentCodePoint() Returns the codepoint at the current index.
CharacterIterator	getCharacterIterator() Returns a java.text.CharacterIterator object for the underlying text of this iterator.
abstract int	getIndex() Gets the current index in text.
static UCharacterIterator	getInstance(char[] source) Returns a UCharacterIterator object given a source character array.
static UCharacterIterator	getInstance(char[] source, int start, int limit) Returns a UCharacterIterator object given a source character array.
static UCharacterIterator	getInstance(CharacterIterator source) Returns a UCharacterIterator object given a CharacterIterator.
static UCharacterIterator	getInstance(Replaceable source) Returns a UCharacterIterator object given a Replaceable object.
static UCharacterIterator	getInstance(String source) Returns a UCharacterIterator object given a source string.
static UCharacterIterator	getInstance(StringBuffer source) Returns a UCharacterIterator object given a source StringBuffer.
abstract int	getLength() Returns the length of the text
String	getText() Convenience method for returning the underlying text storage as as string
int	getText(char[] fillIn) Convenience override for getText(char[], int) that provides an offset of 0.
abstract int	getText(char[] fillIn, int offset) Fills the buffer with the underlying text storage of the iterator If the buffer capacity is not enough a exception is thrown.
int	moveCodePointIndex(int delta) Moves the current position by the number of code points specified, either forward or backward depending on the sign of delta (positive or negative respectively).
int	moveIndex(int delta) Moves the current position by the number of code units specified, either forward or backward depending on the sign of delta (positive or negative respectively).
abstract int	next() Returns the UTF16 code unit at index, and increments to the next code unit (post-increment semantics).
int	nextCodePoint() Returns the code point at index, and increments to the next code point (post-increment semantics).
abstract int	previous() Decrement to the position of the previous code unit in the text, and return it (pre-decrement semantics).
int	previousCodePoint() Retreat to the start of the previous code point in the text, and return it (pre-decrement semantics).
abstract void	setIndex(int index) Sets the index to the specified index in the text.
void	setToLimit() Sets the current index to the limit.
void	setToStart() Sets the current index to the start.

Methods inherited from class java.lang.Object

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

Constructor Detail

UCharacterIterator

protected UCharacterIterator()

Protected default constructor for the subclasses

Status:

Stable ICU 2.4.

Method Detail

getInstance

public static final UCharacterIterator getInstance(Replaceable source)

Returns a UCharacterIterator object given a Replaceable object.

Parameters:

source - a valid source as a Replaceable object

Returns:

UCharacterIterator object

Throws:

IllegalArgumentException - if the argument is null

Status:

Stable ICU 2.4.

getInstance

public static final UCharacterIterator getInstance(String source)

Returns a UCharacterIterator object given a source string.

Parameters:

source - a string

Returns:

UCharacterIterator object

Throws:

IllegalArgumentException - if the argument is null

Status:

Stable ICU 2.4.

getInstance

public static final UCharacterIterator getInstance(char[] source)

Returns a UCharacterIterator object given a source character array.

Parameters:

source - an array of UTF-16 code units

Returns:

UCharacterIterator object

Throws:

IllegalArgumentException - if the argument is null

Status:

Stable ICU 2.4.

getInstance

public static final UCharacterIterator getInstance(char[] source,
                                                   int start,
                                                   int limit)

Returns a UCharacterIterator object given a source character array.

Parameters:

source - an array of UTF-16 code units

Returns:

UCharacterIterator object

Throws:

IllegalArgumentException - if the argument is null

Status:

Stable ICU 2.4.

getInstance

public static final UCharacterIterator getInstance(StringBuffer source)

Returns a UCharacterIterator object given a source StringBuffer.

Parameters:

source - an string buffer of UTF-16 code units

Returns:

UCharacterIterator object

Throws:

IllegalArgumentException - if the argument is null

Status:

Stable ICU 2.4.

getInstance

public static final UCharacterIterator getInstance(CharacterIterator source)

Returns a UCharacterIterator object given a CharacterIterator.

Parameters:

source - a valid CharacterIterator object.

Returns:

UCharacterIterator object

Throws:

IllegalArgumentException - if the argument is null

Status:

Stable ICU 2.4.

getCharacterIterator

public CharacterIterator getCharacterIterator()

Returns a java.text.CharacterIterator object for the underlying text of this iterator. The returned iterator is independent of this iterator.

Returns:

java.text.CharacterIterator object

Status:

Stable ICU 2.4.

current

public abstract int current()

Returns the code unit at the current index. If index is out of range, returns DONE. Index is not changed.

Returns:

current code unit

Status:

Stable ICU 2.4.

currentCodePoint

public int currentCodePoint()

Returns the codepoint at the current index. If the current index is invalid, DONE is returned. If the current index points to a lead surrogate, and there is a following trail surrogate, then the code point is returned. Otherwise, the code unit at index is returned. Index is not changed.

Returns:

current codepoint

Status:

Stable ICU 2.4.

getLength

public abstract int getLength()

Returns the length of the text

Returns:

length of the text

Status:

Stable ICU 2.4.

getIndex

public abstract int getIndex()

Gets the current index in text.

Returns:

current index in text.

Status:

Stable ICU 2.4.

next

public abstract int next()

Returns the UTF16 code unit at index, and increments to the next code unit (post-increment semantics). If index is out of range, DONE is returned, and the iterator is reset to the limit of the text.

Specified by:

next in interface UForwardCharacterIterator

Returns:

the next UTF16 code unit, or DONE if the index is at the limit of the text.

Status:

Stable ICU 2.4.

nextCodePoint

public int nextCodePoint()

Returns the code point at index, and increments to the next code point (post-increment semantics). If index does not point to a valid surrogate pair, the behavior is the same as next(). Otherwise the iterator is incremented past the surrogate pair, and the code point represented by the pair is returned.

Specified by:

nextCodePoint in interface UForwardCharacterIterator

Returns:

the next codepoint in text, or DONE if the index is at the limit of the text.

Status:

Stable ICU 2.4.

previous

public abstract int previous()

Decrement to the position of the previous code unit in the text, and return it (pre-decrement semantics). If the resulting index is less than 0, the index is reset to 0 and DONE is returned.

Returns:

the previous code unit in the text, or DONE if the new index is before the start of the text.

Status:

Stable ICU 2.4.

previousCodePoint

public int previousCodePoint()

Retreat to the start of the previous code point in the text, and return it (pre-decrement semantics). If the index is not preceded by a valid surrogate pair, the behavior is the same as previous(). Otherwise the iterator is decremented to the start of the surrogate pair, and the code point represented by the pair is returned.

Returns:

the previous code point in the text, or DONE if the new index is before the start of the text.

Status:

Stable ICU 2.4.

setIndex

public abstract void setIndex(int index)

Sets the index to the specified index in the text.

Parameters:

index - the index within the text.

Throws:

IndexOutOfBoundsException - is thrown if an invalid index is supplied

Status:

Stable ICU 2.4.

setToLimit

public void setToLimit()

Sets the current index to the limit.

Status:

Stable ICU 2.4.

setToStart

public void setToStart()

Sets the current index to the start.

Status:

Stable ICU 2.4.

getText

public abstract int getText(char[] fillIn,
                            int offset)

Fills the buffer with the underlying text storage of the iterator If the buffer capacity is not enough a exception is thrown. The capacity of the fill in buffer should at least be equal to length of text in the iterator obtained by calling getLength()). Usage:

         UChacterIterator iter = new UCharacterIterator.getInstance(text);
         char[] buf = new char[iter.getLength()];
         iter.getText(buf);

         OR
         char[] buf= new char[1];
         int len = 0;
         for(;;){
             try{
                 len = iter.getText(buf);
                 break;
             }catch(IndexOutOfBoundsException e){
                 buf = new char[iter.getLength()];
             }
         }
 

Parameters:

fillIn - an array of chars to fill with the underlying UTF-16 code units.

offset - the position within the array to start putting the data.

Returns:

the number of code units added to fillIn, as a convenience

Throws:

IndexOutOfBoundsException - exception if there is not enough room after offset in the array, or if offset < 0.

Status:

Stable ICU 2.4.

getText

public final int getText(char[] fillIn)

Convenience override for getText(char[], int) that provides an offset of 0.

Parameters:

fillIn - an array of chars to fill with the underlying UTF-16 code units.

Returns:

the number of code units added to fillIn, as a convenience

Throws:

IndexOutOfBoundsException - exception if there is not enough room in the array.

Status:

Stable ICU 2.4.

getText

public String getText()

Convenience method for returning the underlying text storage as as string

Returns:

the underlying text storage in the iterator as a string

Status:

Stable ICU 2.4.

moveIndex

public int moveIndex(int delta)

Moves the current position by the number of code units specified, either forward or backward depending on the sign of delta (positive or negative respectively). If the resulting index would be less than zero, the index is set to zero, and if the resulting index would be greater than limit, the index is set to limit.

Parameters:

delta - the number of code units to move the current index.

Returns:

the new index.

Throws:

IndexOutOfBoundsException - is thrown if an invalid index is supplied

Status:

Stable ICU 2.4.

moveCodePointIndex

public int moveCodePointIndex(int delta)

Moves the current position by the number of code points specified, either forward or backward depending on the sign of delta (positive or negative respectively). If the current index is at a trail surrogate then the first adjustment is by code unit, and the remaining adjustments are by code points. If the resulting index would be less than zero, the index is set to zero, and if the resulting index would be greater than limit, the index is set to limit.

Parameters:

delta - the number of code units to move the current index.

Returns:

the new index

Throws:

IndexOutOfBoundsException - is thrown if an invalid delta is supplied

Status:

Stable ICU 2.4.

clone

public Object clone()
             throws CloneNotSupportedException

Creates a copy of this iterator, independent from other iterators. If it is not possible to clone the iterator, returns null.

Overrides:

clone in class Object

Returns:

copy of this iterator

Throws:

CloneNotSupportedException

Status:

Stable ICU 2.4.