274 lines
8.4 KiB
Java
274 lines
8.4 KiB
Java
/* java.util.StringTokenizer
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Copyright (C) 1998, 1999, 2001 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.util;
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/**
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* This class splits a string into tokens. The caller can set on which
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* delimiters the string should be split and if the delimiters should be
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* returned.
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*
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* You may change the delimiter set on the fly by calling
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* nextToken(String). But the semantic is quite difficult; it even
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* depends on calling <code>hasMoreTokens()</code>. You should call
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* <code>hasMoreTokens()</code> before, otherwise the old delimiters
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* after the last token are returned.
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*
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* If you want to get the delimiters, you have to use the three argument
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* constructor. The delimiters are returned as token consisting of a
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* single character.
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*
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* @author Jochen Hoenicke
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* @author Warren Levy <warrenl@cygnus.com>
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*/
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public class StringTokenizer implements Enumeration
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{
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/**
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* The position in the str, where we currently are.
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*/
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private int pos;
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/**
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* The string that should be split into tokens.
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*/
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private String str;
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/**
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* The string containing the delimiter characters.
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*/
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private String delim;
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/**
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* Tells, if we should return the delimiters.
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*/
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private boolean retDelims;
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/*{
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invariant {
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pos >= 0 :: "position is negative";
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pos <= str.length() :: "position is out of string";
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str != null :: "String is null";
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delim != null :: "Delimiters are null";
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}
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} */
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/**
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* Creates a new StringTokenizer for the string <code>str</code>,
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* that should split on the default delimiter set (space, tap,
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* newline, return and formfeed), and which doesn't return the
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* delimiters.
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* @param str The string to split.
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*/
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public StringTokenizer(String str)
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/*{ require { str != null :: "str must not be null"; } } */
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{
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this(str, " \t\n\r\f", false);
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}
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/**
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* Create a new StringTokenizer, that splits the given string on
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* the given delimiter characters. It doesn't return the delimiter
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* characters.
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*
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* @param str The string to split.
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* @param delim A string containing all delimiter characters.
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*/
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public StringTokenizer(String str, String delim)
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/*{ require { str != null :: "str must not be null";
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delim != null :: "delim must not be null"; } } */
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{
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this(str, delim, false);
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}
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/**
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* Create a new StringTokenizer, that splits the given string on
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* the given delimiter characters. If you set
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* <code>returnDelims</code> to <code>true</code>, the delimiter
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* characters are returned as tokens of their own. The delimiter
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* tokens always consist of a single character.
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*
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* @param str The string to split.
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* @param delim A string containing all delimiter characters.
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* @param returnDelims Tells, if you want to get the delimiters.
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*/
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public StringTokenizer(String str, String delim, boolean returnDelims)
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/*{ require { str != null :: "str must not be null";
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delim != null :: "delim must not be null"; } } */
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{
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this.str = str;
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this.delim = delim;
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this.retDelims = returnDelims;
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this.pos = 0;
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}
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/**
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* Tells if there are more tokens.
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* @return True, if the next call of nextToken() succeeds, false otherwise.
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*/
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public boolean hasMoreTokens()
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{
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if (!retDelims)
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{
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while (pos < str.length() && delim.indexOf(str.charAt(pos)) > -1)
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{
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pos++;
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}
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}
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return pos < str.length();
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}
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/**
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* Returns the nextToken, changing the delimiter set to the given
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* <code>delim</code>. The change of the delimiter set is
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* permanent, ie. the next call of nextToken(), uses the same
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* delimiter set.
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* @param delim a string containing the new delimiter characters.
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* @return the next token with respect to the new delimiter characters.
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* @exception NoSuchElementException if there are no more tokens.
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*/
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public String nextToken(String delim) throws NoSuchElementException
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/*{ require { hasMoreTokens() :: "no more Tokens available";
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ensure { $return != null && $return.length() > 0; } } */
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{
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this.delim = delim;
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return nextToken();
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}
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/**
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* Returns the nextToken of the string.
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* @param delim a string containing the new delimiter characters.
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* @return the next token with respect to the new delimiter characters.
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* @exception NoSuchElementException if there are no more tokens.
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*/
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public String nextToken() throws NoSuchElementException
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/*{ require { hasMoreTokens() :: "no more Tokens available";
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ensure { $return != null && $return.length() > 0; } } */
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{
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if (pos < str.length() && delim.indexOf(str.charAt(pos)) > -1)
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{
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if (retDelims)
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return str.substring(pos, ++pos);
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while (++pos < str.length() && delim.indexOf(str.charAt(pos)) > -1)
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{
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/* empty */
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}
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}
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if (pos < str.length())
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{
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int start = pos;
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while (++pos < str.length() && delim.indexOf(str.charAt(pos)) == -1)
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{
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/* empty */
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}
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return str.substring(start, pos);
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}
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throw new NoSuchElementException();
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}
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/**
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* This does the same as hasMoreTokens. This is the
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* <code>Enumeration</code interface method.
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* @return True, if the next call of nextElement() succeeds, false
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* otherwise.
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* @see #hasMoreTokens
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*/
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public boolean hasMoreElements()
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{
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return hasMoreTokens();
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}
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/**
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* This does the same as nextTokens. This is the
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* <code>Enumeration</code interface method.
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* @return the next token with respect to the new delimiter characters.
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* @exception NoSuchElementException if there are no more tokens.
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* @see #nextToken
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*/
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public Object nextElement() throws NoSuchElementException
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{
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return nextToken();
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}
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/**
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* This counts the number of remaining tokens in the string, with
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* respect to the current delimiter set.
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* @return the number of times <code>nextTokens()</code> will
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* succeed.
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* @see #nextToken
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*/
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public int countTokens()
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{
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int count = 0;
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int delimiterCount = 0;
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boolean tokenFound = false; // Set when a non-delimiter is found
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int tmpPos = pos;
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// Note for efficiency, we count up the delimiters rather than check
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// retDelims every time we encounter one. That way, we can
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// just do the conditional once at the end of the method
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while (tmpPos < str.length())
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{
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if (delim.indexOf(str.charAt(tmpPos++)) > -1)
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{
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if (tokenFound)
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{
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// Got to the end of a token
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count++;
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tokenFound = false;
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}
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delimiterCount++; // Increment for this delimiter
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}
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else
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{
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tokenFound = true;
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// Get to the end of the token
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while (tmpPos < str.length()
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&& delim.indexOf(str.charAt(tmpPos)) == -1)
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++tmpPos;
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}
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}
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// Make sure to count the last token
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if (tokenFound)
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count++;
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// if counting delmiters add them into the token count
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return retDelims ? count + delimiterCount : count;
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}
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}
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