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International Component for Unicode for Java (ICU4J) is a mature, widely used Java library
providing Unicode and Globalization support
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
* Copyright (C) 1996-2015, International Business Machines Corporation and
* others. All Rights Reserved.
*******************************************************************************
*/
package com.ibm.icu.impl;
import com.ibm.icu.text.Replaceable;
import com.ibm.icu.text.ReplaceableString;
import com.ibm.icu.text.UCharacterIterator;
import com.ibm.icu.text.UTF16;
/**
* DLF docs must define behavior when Replaceable is mutated underneath
* the iterator.
*
* This and ICUCharacterIterator share some code, maybe they should share
* an implementation, or the common state and implementation should be
* moved up into UCharacterIterator.
*
* What are first, last, and getBeginIndex doing here?!?!?!
*/
public class ReplaceableUCharacterIterator extends UCharacterIterator {
// public constructor ------------------------------------------------------
/**
* Public constructor
* @param replaceable text which the iterator will be based on
*/
public ReplaceableUCharacterIterator(Replaceable replaceable){
if(replaceable==null){
throw new IllegalArgumentException();
}
this.replaceable = replaceable;
this.currentIndex = 0;
}
/**
* Public constructor
* @param str text which the iterator will be based on
*/
public ReplaceableUCharacterIterator(String str){
if(str==null){
throw new IllegalArgumentException();
}
this.replaceable = new ReplaceableString(str);
this.currentIndex = 0;
}
/**
* Public constructor
* @param buf buffer of text on which the iterator will be based
*/
public ReplaceableUCharacterIterator(StringBuffer buf){
if(buf==null){
throw new IllegalArgumentException();
}
this.replaceable = new ReplaceableString(buf);
this.currentIndex = 0;
}
// public methods ----------------------------------------------------------
/**
* Creates a copy of this iterator, does not clone the underlying
* Replaceableobject
* @return copy of this iterator
*/
@Override
public Object clone(){
try {
return super.clone();
} catch (CloneNotSupportedException e) {
return null; // never invoked
}
}
/**
* Returns the current UTF16 character.
* @return current UTF16 character
*/
@Override
public int current(){
if (currentIndex < replaceable.length()) {
return replaceable.charAt(currentIndex);
}
return DONE;
}
/**
* Returns the current codepoint
* @return current codepoint
*/
@Override
public int currentCodePoint(){
// cannot use charAt due to it different
// behaviour when index is pointing at a
// trail surrogate, check for surrogates
int ch = current();
if(UTF16.isLeadSurrogate(ch)){
// advance the index to get the next code point
next();
// due to post increment semantics current() after next()
// actually returns the next char which is what we want
int ch2 = current();
// current should never change the current index so back off
previous();
if(UTF16.isTrailSurrogate(ch2)){
// we found a surrogate pair
return Character.toCodePoint((char)ch, (char)ch2);
}
}
return ch;
}
/**
* Returns the length of the text
* @return length of the text
*/
@Override
public int getLength(){
return replaceable.length();
}
/**
* Gets the current currentIndex in text.
* @return current currentIndex in text.
*/
@Override
public int getIndex(){
return currentIndex;
}
/**
* Returns next UTF16 character and increments the iterator's currentIndex by 1.
* If the resulting currentIndex is greater or equal to the text length, the
* currentIndex is reset to the text length and a value of DONECODEPOINT is
* returned.
* @return next UTF16 character in text or DONE if the new currentIndex is off the
* end of the text range.
*/
@Override
public int next(){
if (currentIndex < replaceable.length()) {
return replaceable.charAt(currentIndex++);
}
return DONE;
}
/**
* Returns previous UTF16 character and decrements the iterator's currentIndex by
* 1.
* If the resulting currentIndex is less than 0, the currentIndex is reset to 0 and a
* value of DONECODEPOINT is returned.
* @return next UTF16 character in text or DONE if the new currentIndex is off the
* start of the text range.
*/
@Override
public int previous(){
if (currentIndex > 0) {
return replaceable.charAt(--currentIndex);
}
return DONE;
}
/**
* Sets the currentIndex to the specified currentIndex in the text and returns that
* single UTF16 character at currentIndex.
* This assumes the text is stored as 16-bit code units.
* @param currentIndex the currentIndex within the text.
* @exception IllegalArgumentException is thrown if an invalid currentIndex is
* supplied. i.e. currentIndex is out of bounds.
* @returns the character at the specified currentIndex or DONE if the specified
* currentIndex is equal to the end of the text.
*/
@Override
public void setIndex(int currentIndex) throws IndexOutOfBoundsException{
if (currentIndex < 0 || currentIndex > replaceable.length()) {
throw new IndexOutOfBoundsException();
}
this.currentIndex = currentIndex;
}
@Override
public int getText(char[] fillIn, int offset){
int length = replaceable.length();
if(offset < 0 || offset + length > fillIn.length){
throw new IndexOutOfBoundsException(Integer.toString(length));
}
replaceable.getChars(0,length,fillIn,offset);
return length;
}
// private data members ----------------------------------------------------
/**
* Replacable object
*/
private Replaceable replaceable;
/**
* Current currentIndex
*/
private int currentIndex;
}