com.ibm.icu.text

Class UCharacterIterator

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

UNKNOWN: ICU 2.4

Constructor Summary
protected UCharacterIterator()
Protected default constructor for the subclasses
Method Summary
Objectclone()
Creates a copy of this iterator, independent from other iterators.
abstract intcurrent()
Returns the code unit at the current index.
intcurrentCodePoint()
Returns the codepoint at the current index.
CharacterIteratorgetCharacterIterator()
Returns a java.text.CharacterIterator object for the underlying text of this iterator.
abstract intgetIndex()
Gets the current index in text.
static UCharacterIteratorgetInstance(Replaceable source)
Returns a UCharacterIterator object given a Replaceable object.
static UCharacterIteratorgetInstance(String source)
Returns a UCharacterIterator object given a source string.
static UCharacterIteratorgetInstance(char[] source)
Returns a UCharacterIterator object given a source character array.
static UCharacterIteratorgetInstance(char[] source, int start, int limit)
Returns a UCharacterIterator object given a source character array.
static UCharacterIteratorgetInstance(StringBuffer source)
Returns a UCharacterIterator object given a source StringBuffer.
static UCharacterIteratorgetInstance(CharacterIterator source)
Returns a UCharacterIterator object given a CharacterIterator.
abstract intgetLength()
Returns the length of the text
abstract intgetText(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.
intgetText(char[] fillIn)
Convenience override for getText(char[], int)>/code> that provides an offset of 0.
StringgetText()
Convenience method for returning the underlying text storage as as string
intmoveCodePointIndex(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).
intmoveIndex(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 intnext()
Returns the UTF16 code unit at index, and increments to the next code unit (post-increment semantics).
intnextCodePoint()
Returns the code point at index, and increments to the next code point (post-increment semantics).
abstract intprevious()
Decrement to the position of the previous code unit in the text, and return it (pre-decrement semantics).
intpreviousCodePoint()
Retreat to the start of the previous code point in the text, and return it (pre-decrement semantics).
abstract voidsetIndex(int index)
Sets the index to the specified index in the text.
voidsetToLimit()
Sets the current index to the limit.
voidsetToStart()
Sets the current index to the start.

Constructor Detail

UCharacterIterator

protected UCharacterIterator()
Protected default constructor for the subclasses

UNKNOWN: ICU 2.4

Method Detail

clone

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

Returns: copy of this iterator

UNKNOWN: 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

UNKNOWN: 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

UNKNOWN: 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

UNKNOWN: ICU 2.4

getIndex

public abstract int getIndex()
Gets the current index in text.

Returns: current index in text.

UNKNOWN: ICU 2.4

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

UNKNOWN: 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

UNKNOWN: 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

UNKNOWN: 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

UNKNOWN: 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

UNKNOWN: 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

UNKNOWN: ICU 2.4

getLength

public abstract int getLength()
Returns the length of the text

Returns: length of the text

UNKNOWN: 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: IndexOutOfBounds exception if there is not enough room after offset in the array, or if offset < 0.

UNKNOWN: ICU 2.4

getText

public final int getText(char[] fillIn)
Convenience override for getText(char[], int)>/code> 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: IndexOutOfBounds exception if there is not enough room in the array.

UNKNOWN: 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

UNKNOWN: 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

UNKNOWN: 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

UNKNOWN: 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.

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

UNKNOWN: 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.

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

UNKNOWN: 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.

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

UNKNOWN: 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

UNKNOWN: ICU 2.4

setToLimit

public void setToLimit()
Sets the current index to the limit.

UNKNOWN: ICU 2.4

setToStart

public void setToStart()
Sets the current index to the start.

UNKNOWN: ICU 2.4

Copyright (c) 2006 IBM Corporation and others.