Package 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
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Field Summary
Fields inherited from interface com.ibm.icu.text.UForwardCharacterIterator
DONE
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
Protected default constructor for the subclasses -
Method Summary
Modifier and TypeMethodDescriptionclone()
Creates a copy of this iterator, independent from other iterators.abstract int
current()
Returns the code unit at the current index.int
Returns the codepoint at the current index.Returns ajava.text.CharacterIterator
object for the underlying text of this iterator.abstract int
getIndex()
Gets the current index in text.static final UCharacterIterator
getInstance
(char[] source) Returns aUCharacterIterator
object given a source character array.static final UCharacterIterator
getInstance
(char[] source, int start, int limit) Returns aUCharacterIterator
object given a source character array.static final UCharacterIterator
getInstance
(Replaceable source) Returns aUCharacterIterator
object given aReplaceable
object.static final UCharacterIterator
getInstance
(String source) Returns aUCharacterIterator
object given a source string.static final UCharacterIterator
getInstance
(StringBuffer source) Returns aUCharacterIterator
object given a source StringBuffer.static final UCharacterIterator
getInstance
(CharacterIterator source) Returns aUCharacterIterator
object given a CharacterIterator.abstract int
Returns the length of the textgetText()
Convenience method for returning the underlying text storage as as stringfinal int
getText
(char[] fillIn) Convenience override forgetText(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
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
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
Sets the current index to the limit.void
Sets the current index to the start.
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Constructor Details
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UCharacterIterator
protected UCharacterIterator()Protected default constructor for the subclasses
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Method Details
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getInstance
Returns aUCharacterIterator
object given aReplaceable
object.- Parameters:
source
- a valid source as aReplaceable
object- Returns:
- UCharacterIterator object
- Throws:
IllegalArgumentException
- if the argument is null
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getInstance
Returns aUCharacterIterator
object given a source string.- Parameters:
source
- a string- Returns:
- UCharacterIterator object
- Throws:
IllegalArgumentException
- if the argument is null
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getInstance
Returns aUCharacterIterator
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
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getInstance
Returns aUCharacterIterator
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
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getInstance
Returns aUCharacterIterator
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
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getInstance
Returns aUCharacterIterator
object given a CharacterIterator.- Parameters:
source
- a valid CharacterIterator object.- Returns:
- UCharacterIterator object
- Throws:
IllegalArgumentException
- if the argument is null
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getCharacterIterator
Returns ajava.text.CharacterIterator
object for the underlying text of this iterator. The returned iterator is independent of this iterator.- Returns:
- java.text.CharacterIterator object
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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
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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
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getLength
public abstract int getLength()Returns the length of the text- Returns:
- length of the text
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getIndex
public abstract int getIndex()Gets the current index in text.- Returns:
- current index in text.
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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 interfaceUForwardCharacterIterator
- Returns:
- the next UTF16 code unit, or DONE if the index is at the limit of the text.
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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 asnext()
. Otherwise the iterator is incremented past the surrogate pair, and the code point represented by the pair is returned.- Specified by:
nextCodePoint
in interfaceUForwardCharacterIterator
- Returns:
- the next codepoint in text, or DONE if the index is at the limit of the text.
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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.
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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 asprevious()
. 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.
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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
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setToLimit
public void setToLimit()Sets the current index to the limit. -
setToStart
public void setToStart()Sets the current index to the start. -
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 callinggetLength()
). 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.
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getText
public final int getText(char[] fillIn) Convenience override forgetText(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.
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getText
Convenience method for returning the underlying text storage as as string- Returns:
- the underlying text storage in the iterator as a string
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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
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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
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clone
Creates a copy of this iterator, independent from other iterators. If it is not possible to clone the iterator, returns null.- Overrides:
clone
in classObject
- Returns:
- copy of this iterator
- Throws:
CloneNotSupportedException
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