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*******************************************************************************
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* Copyright (C) 1996-2006, International Business Machines Corporation and *
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* others. All Rights Reserved. *
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*******************************************************************************
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package com.ibm.icu.impl;
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import com.ibm.icu.text.UCharacterIterator;
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* Used by Collation. UCharacterIterator on Strings. Can't use
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* ReplaceableUCharacterIterator because it is not easy to do a fast setText.
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// TODO: Investivate if setText is a feature required by users so that we can
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// move this method to the base class!
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public final class StringUCharacterIterator extends UCharacterIterator
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// public constructor ------------------------------------------------------
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* @param str text which the iterator will be based on
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public StringUCharacterIterator(String str)
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throw new IllegalArgumentException();
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* Public default constructor
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public StringUCharacterIterator()
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// public methods ----------------------------------------------------------
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* Creates a copy of this iterator, does not clone the underlying
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* <code>String</code>object
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* @return copy of this iterator
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} catch (CloneNotSupportedException e) {
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return null; // never invoked
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* Returns the current UTF16 character.
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* @return current UTF16 character
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if (m_currentIndex_ < m_text_.length()) {
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return m_text_.charAt(m_currentIndex_);
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* Returns the length of the text
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* @return length of the text
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public int getLength()
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return m_text_.length();
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* Gets the current currentIndex in text.
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* @return current currentIndex in text.
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return m_currentIndex_;
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* Returns next UTF16 character and increments the iterator's currentIndex
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* If the resulting currentIndex is greater or equal to the text length,
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* the currentIndex is reset to the text length and a value of DONE is
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* @return next UTF16 character in text or DONE if the new currentIndex is
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* off the end of the text range.
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if (m_currentIndex_ < m_text_.length())
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return m_text_.charAt(m_currentIndex_ ++);
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* Returns previous UTF16 character and decrements the iterator's
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* If the resulting currentIndex is less than 0, the currentIndex is reset
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* to 0 and a value of DONE is returned.
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* @return next UTF16 character in text or DONE if the new currentIndex is
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* off the start of the text range.
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public int previous()
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if (m_currentIndex_ > 0) {
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return m_text_.charAt(-- m_currentIndex_);
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* <p>Sets the currentIndex to the specified currentIndex in the text and
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* returns that single UTF16 character at currentIndex.
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* This assumes the text is stored as 16-bit code units.</p>
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* @param currentIndex the currentIndex within the text.
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* @exception IndexOutOfBoundsException is thrown if an invalid currentIndex
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* is supplied. i.e. currentIndex is out of bounds.
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public void setIndex(int currentIndex) throws IndexOutOfBoundsException
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if (currentIndex < 0 || currentIndex > m_text_.length()) {
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throw new IndexOutOfBoundsException();
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m_currentIndex_ = currentIndex;
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* Fills the buffer with the underlying text storage of the iterator
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* If the buffer capacity is not enough a exception is thrown. The capacity
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* of the fill in buffer should at least be equal to length of text in the
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* iterator obtained by calling <code>getLength()</code).
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* UChacterIterator iter = new UCharacterIterator.getInstance(text);
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* char[] buf = new char[iter.getLength()];
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* char[] buf= new char[1];
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* len = iter.getText(buf);
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* }catch(IndexOutOfBoundsException e){
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* buf = new char[iter.getLength()];
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* @param fillIn an array of chars to fill with the underlying UTF-16 code
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* @param offset the position within the array to start putting the data.
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* @return the number of code units added to fillIn, as a convenience
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* @exception IndexOutOfBoundsException exception if there is not enough
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* room after offset in the array, or if offset < 0.
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public int getText(char[] fillIn, int offset)
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int length = m_text_.length();
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if (offset < 0 || offset + length > fillIn.length) {
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throw new IndexOutOfBoundsException(Integer.toString(length));
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m_text_.getChars(0, length, fillIn, offset);
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* Convenience method for returning the underlying text storage as as
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* @return the underlying text storage in the iterator as a string
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public String getText()
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* Reset this iterator to point to a new string. This method is used by
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* other classes that want to avoid allocating new
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* ReplaceableCharacterIterator objects every time their setText method
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* @param text The String to be iterated over
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public void setText(String text)
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throw new NullPointerException();
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// private data members ----------------------------------------------------
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private String m_text_;
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* Current currentIndex
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private int m_currentIndex_;