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UCharacterIterator

public abstract class UCharacterIterator
extends Object implements Cloneable

java.lang.Object
   ↳ android.icu.text.UCharacterIterator


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)

Summary

Constants

int DONE

Indicator that we have reached the ends of the UTF16 text.

Protected constructors

UCharacterIterator()

Protected default constructor for the subclasses

Public methods

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 final UCharacterIterator getInstance(String source)

Returns a UCharacterIterator object given a source string.

static final UCharacterIterator getInstance(StringBuffer source)

Returns a UCharacterIterator object given a source StringBuffer.

static final UCharacterIterator getInstance(Replaceable source)

Returns a UCharacterIterator object given a Replaceable object.

static final UCharacterIterator getInstance(CharacterIterator source)

Returns a UCharacterIterator object given a CharacterIterator.

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

Returns a UCharacterIterator object given a source character array.

static final UCharacterIterator getInstance(char[] source)

Returns a UCharacterIterator object given a source character array.

abstract int getLength()

Returns the length of the text

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.

String getText()

Convenience method for returning the underlying text storage as as string

final int getText(char[] fillIn)

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

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.

Inherited methods

From class java.lang.Object

Constants

DONE

added in API level 24
int DONE

Indicator that we have reached the ends of the UTF16 text.

Constant Value: -1 (0xffffffff)

Protected constructors

UCharacterIterator

added in API level 24
UCharacterIterator ()

Protected default constructor for the subclasses

Public methods

clone

added in API level 24
Object clone ()

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

Returns
Object copy of this iterator

Throws
CloneNotSupportedException

current

added in API level 24
int current ()

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

Returns
int current code unit

currentCodePoint

added in API level 24
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
int current codepoint

getCharacterIterator

added in API level 24
CharacterIterator getCharacterIterator ()

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

Returns
CharacterIterator java.text.CharacterIterator object

getIndex

added in API level 24
int getIndex ()

Gets the current index in text.

Returns
int current index in text.

getInstance

added in API level 24
UCharacterIterator getInstance (String source)

Returns a UCharacterIterator object given a source string.

Parameters
source String: a string

Returns
UCharacterIterator UCharacterIterator object

Throws
IllegalArgumentException if the argument is null

getInstance

added in API level 24
UCharacterIterator getInstance (StringBuffer source)

Returns a UCharacterIterator object given a source StringBuffer.

Parameters
source StringBuffer: an string buffer of UTF-16 code units

Returns
UCharacterIterator UCharacterIterator object

Throws
IllegalArgumentException if the argument is null

getInstance

added in API level 24
UCharacterIterator getInstance (Replaceable source)

Returns a UCharacterIterator object given a Replaceable object.

Parameters
source Replaceable: a valid source as a Replaceable object

Returns
UCharacterIterator UCharacterIterator object

Throws
IllegalArgumentException if the argument is null

getInstance

added in API level 24
UCharacterIterator getInstance (CharacterIterator source)

Returns a UCharacterIterator object given a CharacterIterator.

Parameters
source CharacterIterator: a valid CharacterIterator object.

Returns
UCharacterIterator UCharacterIterator object

Throws
IllegalArgumentException if the argument is null

getInstance

added in API level 24
UCharacterIterator getInstance (char[] source, 
                int start, 
                int limit)

Returns a UCharacterIterator object given a source character array.

Parameters
source char: an array of UTF-16 code units

start int

limit int

Returns
UCharacterIterator UCharacterIterator object

Throws
IllegalArgumentException if the argument is null

getInstance

added in API level 24
UCharacterIterator getInstance (char[] source)

Returns a UCharacterIterator object given a source character array.

Parameters
source char: an array of UTF-16 code units

Returns
UCharacterIterator UCharacterIterator object

Throws
IllegalArgumentException if the argument is null

getLength

added in API level 24
int getLength ()

Returns the length of the text

Returns
int length of the text

getText

added in API level 24
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 char: an array of chars to fill with the underlying UTF-16 code units.

offset int: the position within the array to start putting the data.

Returns
int 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.

getText

added in API level 24
String getText ()

Convenience method for returning the underlying text storage as as string

Returns
String the underlying text storage in the iterator as a string

getText

added in API level 24
int getText (char[] fillIn)

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

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

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

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

moveCodePointIndex

added in API level 24
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 int: the number of code units to move the current index.

Returns
int the new index

Throws
IndexOutOfBoundsException is thrown if an invalid delta is supplied

moveIndex

added in API level 24
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 int: the number of code units to move the current index.

Returns
int the new index.

Throws
IndexOutOfBoundsException is thrown if an invalid index is supplied

next

added in API level 24
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.

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

nextCodePoint

added in API level 24
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.

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

previous

added in API level 24
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
int the previous code unit in the text, or DONE if the new index is before the start of the text.

previousCodePoint

added in API level 24
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 preceeded 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
int the previous code point in the text, or DONE if the new index is before the start of the text.

setIndex

added in API level 24
void setIndex (int index)

Sets the index to the specified index in the text.

Parameters
index int: the index within the text.

Throws
IndexOutOfBoundsException is thrown if an invalid index is supplied

setToLimit

added in API level 24
void setToLimit ()

Sets the current index to the limit.

setToStart

added in API level 24
void setToStart ()

Sets the current index to the start.

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