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/*
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* Copyright (c) 1996, 2000, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
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* (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
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*
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* The original version of this source code and documentation
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* is copyrighted and owned by Taligent, Inc., a wholly-owned
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* subsidiary of IBM. These materials are provided under terms
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* of a License Agreement between Taligent and Sun. This technology
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* is protected by multiple US and International patents.
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*
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* This notice and attribution to Taligent may not be removed.
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* Taligent is a registered trademark of Taligent, Inc.
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*
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*/
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package java.text;
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/**
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* This interface defines a protocol for bidirectional iteration over text.
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* The iterator iterates over a bounded sequence of characters. Characters
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* are indexed with values beginning with the value returned by getBeginIndex() and
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* continuing through the value returned by getEndIndex()-1.
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* <p>
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* Iterators maintain a current character index, whose valid range is from
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* getBeginIndex() to getEndIndex(); the value getEndIndex() is included to allow
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* handling of zero-length text ranges and for historical reasons.
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* The current index can be retrieved by calling getIndex() and set directly
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* by calling setIndex(), first(), and last().
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* <p>
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* The methods previous() and next() are used for iteration. They return DONE if
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* they would move outside the range from getBeginIndex() to getEndIndex() -1,
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* signaling that the iterator has reached the end of the sequence. DONE is
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* also returned by other methods to indicate that the current index is
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* outside this range.
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*
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* <P>Examples:<P>
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*
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* Traverse the text from start to finish
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* <pre>
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* public void traverseForward(CharacterIterator iter) {
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* for(char c = iter.first(); c != CharacterIterator.DONE; c = iter.next()) {
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* processChar(c);
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* }
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* }
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* </pre>
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*
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* Traverse the text backwards, from end to start
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* <pre>
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* public void traverseBackward(CharacterIterator iter) {
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* for(char c = iter.last(); c != CharacterIterator.DONE; c = iter.previous()) {
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* processChar(c);
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* }
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* }
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* </pre>
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*
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* Traverse both forward and backward from a given position in the text.
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* Calls to notBoundary() in this example represents some
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* additional stopping criteria.
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* <pre>
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* public void traverseOut(CharacterIterator iter, int pos) {
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* for (char c = iter.setIndex(pos);
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* c != CharacterIterator.DONE && notBoundary(c);
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* c = iter.next()) {
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* }
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* int end = iter.getIndex();
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* for (char c = iter.setIndex(pos);
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* c != CharacterIterator.DONE && notBoundary(c);
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* c = iter.previous()) {
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* }
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* int start = iter.getIndex();
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* processSection(start, end);
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* }
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* </pre>
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*
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* @see StringCharacterIterator
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* @see AttributedCharacterIterator
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*/
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public interface CharacterIterator extends Cloneable
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{
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/**
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* Constant that is returned when the iterator has reached either the end
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* or the beginning of the text. The value is '\\uFFFF', the "not a
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* character" value which should not occur in any valid Unicode string.
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*/
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public static final char DONE = '\uFFFF';
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/**
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* Sets the position to getBeginIndex() and returns the character at that
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* position.
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* @return the first character in the text, or DONE if the text is empty
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* @see #getBeginIndex()
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*/
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public char first();
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/**
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* Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty)
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* and returns the character at that position.
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* @return the last character in the text, or DONE if the text is empty
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* @see #getEndIndex()
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*/
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public char last();
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/**
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* Gets the character at the current position (as returned by getIndex()).
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* @return the character at the current position or DONE if the current
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* position is off the end of the text.
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* @see #getIndex()
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*/
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public char current();
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/**
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* Increments the iterator's index by one and returns the character
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* at the new index. If the resulting index is greater or equal
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* to getEndIndex(), the current index is reset to getEndIndex() and
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* a value of DONE is returned.
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* @return the character at the new position or DONE if the new
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* position is off the end of the text range.
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*/
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public char next();
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/**
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* Decrements the iterator's index by one and returns the character
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* at the new index. If the current index is getBeginIndex(), the index
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* remains at getBeginIndex() and a value of DONE is returned.
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* @return the character at the new position or DONE if the current
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* position is equal to getBeginIndex().
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*/
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public char previous();
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/**
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* Sets the position to the specified position in the text and returns that
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* character.
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* @param position the position within the text. Valid values range from
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* getBeginIndex() to getEndIndex(). An IllegalArgumentException is thrown
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* if an invalid value is supplied.
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* @return the character at the specified position or DONE if the specified position is equal to getEndIndex()
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*/
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public char setIndex(int position);
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/**
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* Returns the start index of the text.
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* @return the index at which the text begins.
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*/
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public int getBeginIndex();
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/**
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* Returns the end index of the text. This index is the index of the first
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* character following the end of the text.
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* @return the index after the last character in the text
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*/
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public int getEndIndex();
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/**
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* Returns the current index.
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* @return the current index.
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*/
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public int getIndex();
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/**
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* Create a copy of this iterator
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* @return A copy of this
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*/
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public Object clone();
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}
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