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)
Constants |
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int |
DONE Indicator that we have reached the ends of the UTF16 text. |
Protected constructors |
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UCharacterIterator() Protected default constructor for the subclasses |
Public methods |
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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 |
abstract int |
getIndex() Gets the current index in text. |
static final UCharacterIterator |
getInstance(String source) Returns a |
static final UCharacterIterator |
getInstance(StringBuffer source) Returns a |
static final UCharacterIterator |
getInstance(Replaceable source) Returns a |
static final UCharacterIterator |
getInstance(CharacterIterator source) Returns a |
static final UCharacterIterator |
getInstance(char[] source, int start, int limit) Returns a |
static final UCharacterIterator |
getInstance(char[] source) Returns a |
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 |
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 |
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![]() java.lang.Object
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int DONE
Indicator that we have reached the ends of the UTF16 text.
Constant Value: -1 (0xffffffff)
UCharacterIterator ()
Protected default constructor for the subclasses
Object clone ()
Creates a copy of this iterator, independent from other iterators. If it is not possible to clone the iterator, returns null.
Returns | |
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Object |
copy of this iterator |
Throws | |
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CloneNotSupportedException |
int current ()
Returns the code unit at the current index. If index is out of range, returns DONE. Index is not changed.
Returns | |
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int |
current code unit |
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 | |
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int |
current codepoint |
CharacterIterator getCharacterIterator ()
Returns a java.text.CharacterIterator
object for the underlying text of this iterator. The returned iterator is independent of this iterator.
Returns | |
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CharacterIterator |
java.text.CharacterIterator object |
int getIndex ()
Gets the current index in text.
Returns | |
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int |
current index in text. |
UCharacterIterator getInstance (String source)
Returns a UCharacterIterator
object given a source string.
Parameters | |
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source |
String : a string |
Returns | |
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UCharacterIterator |
UCharacterIterator object |
Throws | |
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IllegalArgumentException |
if the argument is null |
UCharacterIterator getInstance (StringBuffer source)
Returns a UCharacterIterator
object given a source StringBuffer.
Parameters | |
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source |
StringBuffer : an string buffer of UTF-16 code units |
Returns | |
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UCharacterIterator |
UCharacterIterator object |
Throws | |
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IllegalArgumentException |
if the argument is null |
UCharacterIterator getInstance (Replaceable source)
Returns a UCharacterIterator
object given a Replaceable
object.
Parameters | |
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source |
Replaceable : a valid source as a Replaceable object |
Returns | |
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UCharacterIterator |
UCharacterIterator object |
Throws | |
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IllegalArgumentException |
if the argument is null |
UCharacterIterator getInstance (CharacterIterator source)
Returns a UCharacterIterator
object given a CharacterIterator.
Parameters | |
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source |
CharacterIterator : a valid CharacterIterator object. |
Returns | |
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UCharacterIterator |
UCharacterIterator object |
Throws | |
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IllegalArgumentException |
if the argument is null |
UCharacterIterator getInstance (char[] source, int start, int limit)
Returns a UCharacterIterator
object given a source character array.
Parameters | |
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source |
char : an array of UTF-16 code units |
start |
int
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limit |
int
|
Returns | |
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UCharacterIterator |
UCharacterIterator object |
Throws | |
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IllegalArgumentException |
if the argument is null |
UCharacterIterator getInstance (char[] source)
Returns a UCharacterIterator
object given a source character array.
Parameters | |
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source |
char : an array of UTF-16 code units |
Returns | |
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UCharacterIterator |
UCharacterIterator object |
Throws | |
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IllegalArgumentException |
if the argument is null |
int getLength ()
Returns the length of the text
Returns | |
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int |
length of the text |
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 | |
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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 | |
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int |
the number of code units added to fillIn, as a convenience |
Throws | |
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IndexOutOfBoundsException |
exception if there is not enough room after offset in the array, or if offset < 0. |
String getText ()
Convenience method for returning the underlying text storage as as string
Returns | |
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String |
the underlying text storage in the iterator as a string |
int getText (char[] fillIn)
Convenience override for getText(char[], int)
that provides an offset of 0.
Parameters | |
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fillIn |
char : an array of chars to fill with the underlying UTF-16 code units. |
Returns | |
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int |
the number of code units added to fillIn, as a convenience |
Throws | |
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IndexOutOfBoundsException |
exception if there is not enough room in the array. |
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 | |
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delta |
int : the number of code units to move the current index. |
Returns | |
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int |
the new index |
Throws | |
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IndexOutOfBoundsException |
is thrown if an invalid delta is supplied |
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 | |
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delta |
int : the number of code units to move the current index. |
Returns | |
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int |
the new index. |
Throws | |
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IndexOutOfBoundsException |
is thrown if an invalid index is supplied |
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 | |
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int |
the next UTF16 code unit, or DONE if the index is at the limit of the text. |
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 | |
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int |
the next codepoint in text, or DONE if the index is at the limit of the text. |
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 | |
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int |
the previous code unit in the text, or DONE if the new index is before the start of the text. |
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 | |
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int |
the previous code point in the text, or DONE if the new index is before the start of the text. |
void setIndex (int index)
Sets the index to the specified index in the text.
Parameters | |
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index |
int : the index within the text. |
Throws | |
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IndexOutOfBoundsException |
is thrown if an invalid index is supplied |