Break a string into tokens : String split « Data Type « Java

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Break a string into tokens

    

/*
 * A replacement for java.util.StringTokenizer
 * Copyright (C) 2001 Stephen Ostermiller
 * http://ostermiller.org/contact.pl?regarding=Java+Utilities
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * See COPYING.TXT for details.
 */
 import java.util.NoSuchElementException;

/**
 * The string tokenizer class allows an application to break a string into
 * tokens.
 * More information about this class is available from <a target="_top" href=
 * "http://ostermiller.org/utils/StringTokenizer.html">ostermiller.org</a>.
 * <p>
 * The tokenization method is much simpler than the one used by the
 * <code>StreamTokenizer</code> class. The <code>StringTokenizer</code> methods
 * do not distinguish among identifiers, numbers, and quoted strings, nor do
 * they recognize and skip comments.
 * <p>
 * The set of delimiters (the characters that separate tokens) may be specified
 * either at creation time or on a per-token basis.
 * <p>
 * There are two kinds of delimiters: token delimiters and non-token delimiters.
 * A token is either one token delimiter character, or a maximal sequence of
 * consecutive characters that are not delimiters.
 * <p>
 * A <code>StringTokenizer</code> object internally maintains a current
 * position within the string to be tokenized. Some operations advance this
 * current position past the characters processed.
 * <p>
 * The implementation is not thread safe; if a <code>StringTokenizer</code>
 * object is intended to be used in multiple threads, an appropriate wrapper
 * must be provided.
 * <p>
 * The following is one example of the use of the tokenizer. It also
 * demonstrates the usefulness of having both token and non-token delimiters in
 * one <code>StringTokenizer</code>.
 * <p>
 * The code:
 * <blockquote><code>
 * String s = " &nbsp;( &nbsp; aaa  \t &nbsp;* (b+c1 ))";<br>
 * StringTokenizer tokenizer = new StringTokenizer(s, " \t\n\r\f", "()+*");<br>
 * while (tokenizer.hasMoreTokens()) {<br>
 * &nbsp;&nbsp;&nbsp;&nbsp;System.out.println(tokenizer.nextToken());<br>
 * };
 * </code></blockquote>
 * <p>
 * prints the following output:
 * <blockquote>
 * (<br>
 * aaa<br>
 * *<br>
 * (<br>
 * b<br>
 * +<br>
 * c1<br>
 * )<br>
 * )
 * </blockquote>
 * <p>
 * </b>Compatibility with <code>java.util.StringTokenizer</code></b>
 * <p>
 * In the original version of <code>java.util.StringTokenizer</code>, the method
 * <code>nextToken()</code> left the current position after the returned token,
 * and the method <code>hasMoreTokens()</code> moved (as a side effect) the
 * current position before the beginning of the next token. Thus, the code:
 * <blockquote><code>
 * String s = "x=a,b,c";<br>
 * java.util.StringTokenizer tokenizer = new java.util.StringTokenizer(s,"=");<br>
 * System.out.println(tokenizer.nextToken());<br>
 * while (tokenizer.hasMoreTokens()) {<br>
 * &nbsp;&nbsp;&nbsp;&nbsp;System.out.println(tokenizer.nextToken(","));<br>
 * };
 * </code></blockquote>
 * <p>
 * prints the following output:
 * <blockquote>
 * x<br>
 * a<br>
 * b<br>
 * c
 * </blockquote>
 * <p>
 * The Java SDK 1.3 implementation removed the undesired side effect of
 * <code>hasMoreTokens</code> method: now, it does not advance current position.
 * However, after these changes the output of the above code was:
 * <blockquote>
 * x<br>
 * =a<br>
 * b<br>
 * c
 * </blockquote>
 * <p>
 * and there was no good way to produce a second token without "=".
 * <p>
 * To solve the problem, this implementation introduces a new method
 * <code>skipDelimiters()</code>. To produce the original output, the above code
 * should be modified as:
 * <blockquote><code>
 * String s = "x=a,b,c";<br>
 * StringTokenizer tokenizer = new StringTokenizer(s,"=");<br>
 * System.out.println(tokenizer.nextToken());<br>
 * tokenizer.skipDelimiters();<br>
 * while (tokenizer.hasMoreTokens()) {<br>
 * &nbsp;&nbsp;&nbsp;&nbsp;System.out.println(tokenizer.nextToken(","));<br>
 * };
 * </code></blockquote>
 *
 * @author Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities
 * @since ostermillerutils 1.00.00
 */
public class StringTokenizer implements java.util.Enumeration<String>, java.util.Iterator<String> {

  /**
   * The string to be tokenized.
   * The code relies on this to never be null.
   *
   * @since ostermillerutils 1.00.00
   */
  protected String text;

  /**
   * The length of the text.
   * Cached for performance.  This should be set whenever the
   * string we are working with is changed.
   *
   * @since ostermillerutils 1.00.00
   */
  protected int strLength;

  /**
   * The set of non-token delimiters.
   *
   * @since ostermillerutils 1.00.00
   */
  protected String nontokenDelims;

  /**
   * The set of token delimiters.
   *
   * @since ostermillerutils 1.00.00
   */
  protected String tokenDelims;

  /**
   * One of two variables used to maintain state through
   * the tokenizing process.
   * <P>
   * Represents the position at which we should start looking for
   * the next token(the position of the character immediately
   * following the end of the last token, or 0 to start), or
   * -1 if the entire string has been examined.
   *
   * @since ostermillerutils 1.00.00
   */
  protected int position;

  /**
   * One of two variables used to maintain state through
   * the tokenizing process.
   * <p>
   * true if and only if is found that an empty token should
   * be returned or if empty token was the last thing returned.
   * <p>
   * If returnEmptyTokens in false, then this variable will
   * always be false.
   *
   * @since ostermillerutils 1.00.00
   */
  protected boolean emptyReturned;

  /**
   * Stores the value of the delimiter character with the
   * highest value. It is used to optimize the detection of delimiter
   * characters.  The common case will be that the int values of delimiters
   * will be less than that of most characters in the string (, or space less
   * than any letter for example).  Given this, we can check easily check
   * to see if a character is not a delimiter by comparing it to the max
   * delimiter.  If it is greater than the max delimiter, then it is no
   * a delimiter otherwise we have to do some more in depth analysis. (for example
   * search the delimiter string.)  This will reduce the running time of
   * the algorithm not to depend on the length of the delimiter string
   * for the common case.
   *
   * @since ostermillerutils 1.00.00
   */
  protected char maxDelimChar;

  /**
   * Whether empty tokens should be returned.
   * for example, if "" should be returned when text starts with
   * a delimiter, has two delimiters next to each other, or
   * ends with a delimiter.
   *
   * @since ostermillerutils 1.00.00
   */
  protected boolean returnEmptyTokens;

  /**
   * Indicates at which position the delimiters last changed.  This
   * will effect how null tokens are returned.  Any
   * time that delimiters are changed, the string will be treated as if
   * it is being parsed from position zero, for example, null strings are possible
   * at the very beginning.
   *
   * @since ostermillerutils 1.00.00
   */
  protected int delimsChangedPosition;

  /**
   * A cache of the token count.  This variable should be -1 if the token
   * have not yet been counted. It should be greater than or equal to zero
   * if the tokens have been counted.
   *
   * @since ostermillerutils 1.00.00
   */
  protected int tokenCount;

  /**
   * Constructs a string tokenizer for the specified string. Both token and
   * non-token delimiters are specified.
   * <p>
   * The current position is set at the beginning of the string.
   *
   * @param text a string to be parsed.
   * @param nontokenDelims the non-token delimiters, i.e. the delimiters that only separate
   *     tokens and are not returned as separate tokens.
   * @param tokenDelims the token delimiters, i.e. delimiters that both separate tokens,
   *     and are themselves returned as tokens.
   * @throws NullPointerException if text is null.
   *
   * @since ostermillerutils 1.00.00
   */
  public StringTokenizer(String text, String nontokenDelims, String tokenDelims){
    this(text, nontokenDelims, tokenDelims, false);
  }

  /**
   * Constructs a string tokenizer for the specified string. Both token and
   * non-token delimiters are specified and whether or not empty tokens are returned
   * is specified.
   * <p>
   * Empty tokens are tokens that are between consecutive delimiters.
   * <p>
   * It is a primary constructor (i.e. all other constructors are defined in terms
   * of it.)
   * <p>
   * The current position is set at the beginning of the string.
   *
   * @param text a string to be parsed.
   * @param nontokenDelims the non-token delimiters, i.e. the delimiters that only separate
   *     tokens and are not returned as separate tokens.
   * @param tokenDelims the token delimiters, i.e. delimiters that both separate tokens,
   *     and are themselves returned as tokens.
   * @param returnEmptyTokens true if empty tokens may be returned; false otherwise.
   * @throws NullPointerException if text is null.
   *
   * @since ostermillerutils 1.00.00
   */
  public StringTokenizer(String text, String nontokenDelims, String tokenDelims, boolean returnEmptyTokens){
    setDelims(nontokenDelims, tokenDelims);
    setText(text);
    setReturnEmptyTokens(returnEmptyTokens);
  }

  /**
   * Constructs a string tokenizer for the specified string. Either token or
   * non-token delimiters are specified.
   * <p>
   * Is equivalent to:
   * <ul>
   * <li> If the third parameter is <code>false</code> --
   *      <code>StringTokenizer(text, delimiters, null)</code>
   * <li> If the third parameter is <code>true</code> --
   *      <code>StringTokenizer(text, null, delimiters)</code>
   * </ul>
   *
   * @param text a string to be parsed.
   * @param delims the delimiters.
   * @param delimsAreTokens
   *     flag indicating whether the second parameter specifies token or
   *     non-token delimiters: <code>false</code> -- the second parameter
   *     specifies non-token delimiters, the set of token delimiters is
   *     empty; <code>true</code> -- the second parameter specifies token
   *     delimiters, the set of non-token delimiters is empty.
   * @throws NullPointerException if text is null.
   *
   * @since ostermillerutils 1.00.00
   */
  public StringTokenizer(String text, String delims, boolean delimsAreTokens){
    this(text, (delimsAreTokens ? null : delims), (delimsAreTokens ? delims : null));
  }

  /**
   * Constructs a string tokenizer for the specified string. The characters in the
   * <code>nontokenDelims</code> argument are the delimiters for separating
   * tokens. Delimiter characters themselves will not be treated as tokens.
   * <p>
   * Is equivalent to <code>StringTokenizer(text,nontokenDelims, null)</code>.
   *
   * @param text a string to be parsed.
   * @param nontokenDelims the non-token delimiters.
   * @throws NullPointerException if text is null.
   *
   * @since ostermillerutils 1.00.00
   */
  public StringTokenizer(String text, String nontokenDelims){
    this(text, nontokenDelims, null);
  }

  /**
   * Constructs a string tokenizer for the specified string. The tokenizer uses
   * " \t\n\r\f" as a delimiter set of non-token delimiters, and an empty token
   * delimiter set.
   * <p>
   * Is equivalent to <code>StringTokenizer(text, " \t\n\r\f", null);
   *
   * @param text a string to be parsed.
   * @throws NullPointerException if text is null.
   *
   * @since ostermillerutils 1.00.00
   */
  public StringTokenizer(String text){
    this(text, " \t\n\r\f", null);
  }

  /**
   * Set the text to be tokenized in this StringTokenizer.
   * <p>
   * This is useful when for StringTokenizer re-use so that new string tokenizers do not
   * have to be created for each string you want to tokenizer.
   * <p>
   * The string will be tokenized from the beginning of the string.
   *
   * @param text a string to be parsed.
   * @throws NullPointerException if text is null.
   *
   * @since ostermillerutils 1.00.00
   */
  public void setText(String text){
    if (text == null){
      throw new NullPointerException();
    }
    this.text = text;
    strLength = text.length();
    emptyReturned = false;
    // set the position to start evaluation to zero
    // unless the string has no length, in which case
    // the entire string has already been examined.
    position = (strLength > 0 ? 0: -1);
    // because the text was changed since the last time the delimiters
    // were changed we need to set the delimiter changed position
    delimsChangedPosition = 0;
    // The token count changes when the text changes
    tokenCount = -1;
  }

  /**
   * Set the delimiters for this StringTokenizer.
   * The position must be initialized before this method is used.
   * (setText does this and it is called from the constructor)
   *
   * @param nontokenDelims delimiters that should not be returned as tokens.
   * @param tokenDelims delimiters that should be returned as tokens.
   *
   * @since ostermillerutils 1.00.00
   */
  private void setDelims(String nontokenDelims, String tokenDelims){
    this.nontokenDelims = nontokenDelims;
    this.tokenDelims = tokenDelims;
    // If we change delimiters, we do not want to start fresh,
    // without returning empty tokens.
    // the delimiter changed position can never be less than
    // zero, unlike position.
    delimsChangedPosition = (position != -1 ? position : strLength);
    // set the max delimiter
    maxDelimChar = 0;
    for (int i=0; nontokenDelims != null && i < nontokenDelims.length(); i++){
      if (maxDelimChar < nontokenDelims.charAt(i)){
        maxDelimChar = nontokenDelims.charAt(i);
      }
    }
    for (int i=0; tokenDelims != null && i < tokenDelims.length(); i++){
      if (maxDelimChar < tokenDelims.charAt(i)){
        maxDelimChar = tokenDelims.charAt(i);
      }
    }
    // Changing the delimiters may change the number of tokens
    tokenCount = -1;
  }


  /**
   * Tests if there are more tokens available from this tokenizer's string.
   * If this method returns <tt>true</tt>, then a subsequent call to
   * <tt>nextToken</tt> with no argument will successfully return a token.
   * <p>
   * The current position is not changed.
   *
   * @return <code>true</code> if and only if there is at least one token in the
   *          string after the current position; <code>false</code> otherwise.
   *
   * @since ostermillerutils 1.00.00
   */
  public boolean hasMoreTokens(){

    // handle the easy case in which the number
    // of tokens has been counted.
    if (tokenCount == 0){
      return false;
    } else if (tokenCount > 0){
      return true;
    }

    // copy over state variables from the class to local
    // variables so that the state of this object can be
    // restored to the state that it was in before this
    // method was called.
    int savedPosition = position;
    boolean savedEmptyReturned = emptyReturned;

    int workingPosition = position;
    boolean workingEmptyReturned = emptyReturned;
    boolean onToken = advancePosition();
    while(position != workingPosition ||
      emptyReturned != workingEmptyReturned){
      if (onToken){
        // restore object state
        position = savedPosition;
        emptyReturned = savedEmptyReturned;
        return true;
      }
      workingPosition = position;
      workingEmptyReturned = emptyReturned;
      onToken = advancePosition();
    }

    // restore object state
    position = savedPosition;
    emptyReturned = savedEmptyReturned;
    return false;
  }

  /**
   * Returns the next token from this string tokenizer.
   * <p>
   * The current position is set after the token returned.
   *
   * @return the next token from this string tokenizer.
   * @throws NoSuchElementException if there are no more tokens in this tokenizer's string.
   *
   * @since ostermillerutils 1.00.00
   */
  public String nextToken(){
    int workingPosition = position;
    boolean workingEmptyReturned = emptyReturned;
    boolean onToken = advancePosition();
    while(position != workingPosition ||
      emptyReturned != workingEmptyReturned){
      if (onToken){
        // returning a token decreases the token count
        tokenCount--;
        return (emptyReturned ? "" : text.substring(workingPosition, (position != -1) ? position : strLength));
      }
      workingPosition = position;
      workingEmptyReturned = emptyReturned;
      onToken = advancePosition();
    }
    throw new NoSuchElementException();
  }

  /**
   * Advances the current position so it is before the next token.
   * <p>
   * This method skips non-token delimiters but does not skip
   * token delimiters.
   * <p>
   * This method is useful when switching to the new delimiter sets (see the
   * second example in the class comment.)
   *
   * @return <code>true</code> if there are more tokens, <code>false</code> otherwise.
   *
   * @since ostermillerutils 1.00.00
   */
  public boolean skipDelimiters(){
    int workingPosition = position;
    boolean workingEmptyReturned = emptyReturned;
    boolean onToken = advancePosition();

    // skipping delimiters may cause the number of tokens to change
    tokenCount = -1;

    while(position != workingPosition ||
      emptyReturned != workingEmptyReturned){
      if (onToken){
        // restore the state to just as it was before we found
        // this token and return
        position = workingPosition;
        emptyReturned = workingEmptyReturned;
        return true;
      }
      workingPosition = position;
      workingEmptyReturned = emptyReturned;
      onToken = advancePosition();
    }

    // the end of the string was reached
    // without finding any tokens
    return false;
  }

  /**
   * Calculates the number of times that this tokenizer's <code>nextToken</code>
   * method can be called before it generates an exception. The current position
   * is not advanced.
   *
   * @return the number of tokens remaining in the string using the current
   *    delimiter set.
   *
   * @see #nextToken()
   * @since ostermillerutils 1.00.00
   */
  public int countTokens(){

    // return the cached token count if a cache
    // is available.
    if (this.tokenCount >=0){
      return this.tokenCount;
    }

    int tokenCount = 0;

    // copy over state variables from the class to local
    // variables so that the state of this object can be
    // restored to the state that it was in before this
    // method was called.
    int savedPosition = position;
    boolean savedEmptyReturned = emptyReturned;

    int workingPosition = position;
    boolean workingEmptyReturned = emptyReturned;
    boolean onToken = advancePosition();
    while(position != workingPosition ||
      emptyReturned != workingEmptyReturned){
      if (onToken){
        tokenCount++;
      }
      workingPosition = position;
      workingEmptyReturned = emptyReturned;
      onToken = advancePosition();
    }

    // restore object state
    position = savedPosition;
    emptyReturned = savedEmptyReturned;

    // Save the token count in case this is called again
    // so we wouldn't have to do so much work.
    this.tokenCount = tokenCount;

    return tokenCount;
  }

  /**
   * Set the delimiters used to this set of (non-token) delimiters.
   *
   * @param delims the new set of non-token delimiters (the set of token delimiters will be empty).
   *
   * @since ostermillerutils 1.00.00
   */
  public void setDelimiters(String delims){
    setDelims(delims, null);
  }

  /**
   * Set the delimiters used to this set of delimiters.
   *
   * @param delims the new set of delimiters.
   * @param delimsAreTokens flag indicating whether the first parameter specifies
   *    token or non-token delimiters: false -- the first parameter specifies non-token
   *    delimiters, the set of token delimiters is empty; true -- the first parameter
   *    specifies token delimiters, the set of non-token delimiters is empty.
   *
   * @since ostermillerutils 1.00.00
   */
  public void setDelimiters(String delims, boolean delimsAreTokens){
    setDelims((delimsAreTokens ? null : delims), (delimsAreTokens ? delims : null));
  }

  /**
   * Set the delimiters used to this set of delimiters.
   *
   * @param nontokenDelims the new set of non-token delimiters.
   * @param tokenDelims the new set of token delimiters.
   *
   * @since ostermillerutils 1.00.00
   */
  public void setDelimiters(String nontokenDelims, String tokenDelims){
    setDelims(nontokenDelims, tokenDelims);
  }

  /**
   * Set the delimiters used to this set of delimiters.
   *
   * @param nontokenDelims the new set of non-token delimiters.
   * @param tokenDelims the new set of token delimiters.
   * @param returnEmptyTokens true if empty tokens may be returned; false otherwise.
   *
   * @since ostermillerutils 1.00.00
   */
  public void setDelimiters(String nontokenDelims, String tokenDelims, boolean returnEmptyTokens){
    setDelims(nontokenDelims, tokenDelims);
    setReturnEmptyTokens(returnEmptyTokens);
  }

  /**
   * Calculates the number of times that this tokenizer's <code>nextToken</code>
   * method can be called before it generates an exception using the given set of
   * (non-token) delimiters.  The delimiters given will be used for future calls to
   * nextToken() unless new delimiters are given. The current position
   * is not advanced.
   *
   * @param delims the new set of non-token delimiters (the set of token delimiters will be empty).
   * @return the number of tokens remaining in the string using the new
   *    delimiter set.
   *
   * @see #countTokens()
   * @since ostermillerutils 1.00.00
   */
  public int countTokens(String delims){
    setDelims(delims, null);
    return countTokens();
  }

  /**
   * Calculates the number of times that this tokenizer's <code>nextToken</code>
   * method can be called before it generates an exception using the given set of
   * delimiters.  The delimiters given will be used for future calls to
   * nextToken() unless new delimiters are given. The current position
   * is not advanced.
   *
   * @param delims the new set of delimiters.
   * @param delimsAreTokens flag indicating whether the first parameter specifies
   *    token or non-token delimiters: false -- the first parameter specifies non-token
   *    delimiters, the set of token delimiters is empty; true -- the first parameter
   *    specifies token delimiters, the set of non-token delimiters is empty.
   * @return the number of tokens remaining in the string using the new
   *    delimiter set.
   *
   * @see #countTokens()
   * @since ostermillerutils 1.00.00
   */
  public int countTokens(String delims, boolean delimsAreTokens){
    setDelims((delimsAreTokens ? null : delims), (delimsAreTokens ? delims : null));
    return countTokens();
  }

  /**
   * Calculates the number of times that this tokenizer's <code>nextToken</code>
   * method can be called before it generates an exception using the given set of
   * delimiters.  The delimiters given will be used for future calls to
   * nextToken() unless new delimiters are given. The current position
   * is not advanced.
   *
   * @param nontokenDelims the new set of non-token delimiters.
   * @param tokenDelims the new set of token delimiters.
   * @return the number of tokens remaining in the string using the new
   *    delimiter set.
   *
   * @see #countTokens()
   * @since ostermillerutils 1.00.00
   */
  public int countTokens(String nontokenDelims, String tokenDelims){
    setDelims(nontokenDelims, tokenDelims);
    return countTokens();
  }

  /**
   * Calculates the number of times that this tokenizer's <code>nextToken</code>
   * method can be called before it generates an exception using the given set of
   * delimiters.  The delimiters given will be used for future calls to
   * nextToken() unless new delimiters are given. The current position
   * is not advanced.
   *
   * @param nontokenDelims the new set of non-token delimiters.
   * @param tokenDelims the new set of token delimiters.
   * @param returnEmptyTokens true if empty tokens may be returned; false otherwise.
   * @return the number of tokens remaining in the string using the new
   *    delimiter set.
   *
   * @see #countTokens()
   * @since ostermillerutils 1.00.00
   */
  public int countTokens(String nontokenDelims, String tokenDelims, boolean returnEmptyTokens){
    setDelims(nontokenDelims, tokenDelims);
    setReturnEmptyTokens(returnEmptyTokens);
    return countTokens();
  }

  /**
   * Advances the state of the tokenizer to the next token or delimiter.  This method only
   * modifies the class variables position, and emptyReturned.  The type of token that
   * should be emitted can be deduced by examining the changes to these two variables.
   * If there are no more tokens, the state of these variables does not change at all.
   *
   * @return true if we are at a juncture at which a token may be emitted, false otherwise.
   *
   * @since ostermillerutils 1.00.00
   */
  private boolean advancePosition(){
    // if we are returning empty tokens, we are just starting to tokenizer
    // and there is a delimiter at the beginning of the string or the string
    // is empty we need to indicate that there is an empty token at the beginning.
    // The beginning is defined as where the delimiters were last changed.
    if (returnEmptyTokens && !emptyReturned &&
      (delimsChangedPosition == position ||
      (position == -1 && strLength == delimsChangedPosition))){
      if (strLength == delimsChangedPosition){
        // Case in which the string (since delimiter change)
        // is empty, but because we are returning empty
        // tokens, a single empty token should be returned.
        emptyReturned = true;
        return true;
      }
      char c = text.charAt(position);
      if (c <= maxDelimChar &&
        (nontokenDelims != null && nontokenDelims.indexOf(c) != -1) ||
        (tokenDelims != null && tokenDelims.indexOf(c) != -1)){
        // There is delimiter at the very start of the string
        // so we must return an empty token at the beginning.
        emptyReturned = true;
        return true;
      }
    }
    // The main loop
    // Do this as long as parts of the string have yet to be examined
    while (position != -1){
      char c = text.charAt(position);
      if (returnEmptyTokens && !emptyReturned && position > delimsChangedPosition){
        char c1 = text.charAt(position - 1);
        // Examine the current character and the one before it.
        // If both of them are delimiters, then we need to return
        // an empty delimiter.  Note that characters that were examined
        // before the delimiters changed should not be reexamined.
        if (c <= maxDelimChar && c1 <= maxDelimChar &&
          ((nontokenDelims != null && nontokenDelims.indexOf(c) != -1) ||
          (tokenDelims != null && tokenDelims.indexOf(c) != -1)) &&
          ((nontokenDelims != null && nontokenDelims.indexOf(c1) != -1) ||
          (tokenDelims != null && tokenDelims.indexOf(c1) != -1))){
          emptyReturned = true;
          /*System.out.println("Empty token.");*/
          return true;
        }
      }

      int nextDelimiter = (position < strLength - 1 ? indexOfNextDelimiter(position + 1) : -1);
      if (c > maxDelimChar ||
        ((nontokenDelims == null || nontokenDelims.indexOf(c) == -1) &&
        (tokenDelims == null || tokenDelims.indexOf(c) == -1))){
        // token found
        /*System.out.println("Token: '" +
          text.substring(position, (nextDelimiter == -1 ? strLength : nextDelimiter)) +
          "' at " + position + ".");*/
        position = nextDelimiter;
        emptyReturned = false;
        return true;
      } else if (tokenDelims != null && tokenDelims.indexOf(c) != -1) {
        // delimiter that can be returned as a token found
        emptyReturned = false;
        /*System.out.println("Delimiter: '" + c + "' at " + position + ".");*/
        position = (position < strLength -1 ? position +1 : -1);
        return true;
      } else {
        // delimiter that is not a token found.
        emptyReturned = false;
        position = (position < strLength -1 ? position +1 : -1);
        return false;
      }
    }
    // handle the case that a token is at the end of the string and we should
    // return empty tokens.
    if (returnEmptyTokens && !emptyReturned && strLength > 0){
      char c = text.charAt(strLength - 1);
      if (c <= maxDelimChar &&
        (nontokenDelims != null && nontokenDelims.indexOf(c) != -1) ||
        (tokenDelims != null && tokenDelims.indexOf(c) != -1)){
        // empty token at the end of the string found.
        emptyReturned = true;
        /*System.out.println("Empty token at end.");*/
        return true;
      }
    }
    return false;
  }

  /**
   * Returns the next token in this string tokenizer's string.
   * <p>
   * First, the sets of token and non-token delimiters are changed to be the
   * <code>tokenDelims</code> and <code>nontokenDelims</code>, respectively.
   * Then the next token (with respect to new delimiters) in the string after the
   * current position is returned.
   * <p>
   * The current position is set after the token returned.
   * <p>
   * The new delimiter sets remains the used ones after this call.
   *
   * @param nontokenDelims the new set of non-token delimiters.
   * @param tokenDelims the new set of token delimiters.
   * @return the next token, after switching to the new delimiter set.
   * @throws NoSuchElementException if there are no more tokens in this tokenizer's string.
   * @see #nextToken()
   *
   * @since ostermillerutils 1.00.00
   */
  public String nextToken(String nontokenDelims, String tokenDelims){
    setDelims(nontokenDelims, tokenDelims);
    return nextToken();
  }

  /**
   * Returns the next token in this string tokenizer's string.
   * <p>
   * First, the sets of token and non-token delimiters are changed to be the
   * <code>tokenDelims</code> and <code>nontokenDelims</code>, respectively;
   * and whether or not to return empty tokens is set.
   * Then the next token (with respect to new delimiters) in the string after the
   * current position is returned.
   * <p>
   * The current position is set after the token returned.
   * <p>
   * The new delimiter set remains the one used for this call and empty tokens are
   * returned in the future as they are in this call.
   *
   * @param nontokenDelims the new set of non-token delimiters.
   * @param tokenDelims the new set of token delimiters.
   * @param returnEmptyTokens true if empty tokens may be returned; false otherwise.
   * @return the next token, after switching to the new delimiter set.
   * @throws NoSuchElementException if there are no more tokens in this tokenizer's string.
   * @see #nextToken()
   *
   * @since ostermillerutils 1.00.00
   */
  public String nextToken(String nontokenDelims, String tokenDelims, boolean returnEmptyTokens){
    setDelims(nontokenDelims, tokenDelims);
    setReturnEmptyTokens(returnEmptyTokens);
    return nextToken();
  }

  /**
   * Returns the next token in this string tokenizer's string.
   * <p>
   * Is equivalent to:
   * <ul>
   * <li> If the second parameter is <code>false</code> --
   *      <code>nextToken(delimiters, null)</code>
   * <li> If the second parameter is <code>true</code> --
   *      <code>nextToken(null, delimiters)</code>
   * </ul>
   * <p>
   * @param delims the new set of token or non-token delimiters.
   * @param delimsAreTokens
   *     flag indicating whether the first parameter specifies token or
   *     non-token delimiters: <code>false</code> -- the first parameter
   *     specifies non-token delimiters, the set of token delimiters is
   *     empty; <code>true</code> -- the first parameter specifies token
   *     delimiters, the set of non-token delimiters is empty.
   * @return the next token, after switching to the new delimiter set.
   * @throws NoSuchElementException if there are no more tokens in this tokenizer's string.
   *
   * @see #nextToken(String,String)
   * @since ostermillerutils 1.00.00
   */
  public String nextToken(String delims, boolean delimsAreTokens){
    return (delimsAreTokens ? nextToken(null, delims) : nextToken(delims, null));
  }

  /**
   * Returns the next token in this string tokenizer's string.
   * <p>
   * Is equivalent to <code>nextToken(delimiters, null)</code>.
   *
   * @param nontokenDelims the new set of non-token delimiters (the set of
   *     token delimiters will be empty).
   * @return the next token, after switching to the new delimiter set.
   * @throws NoSuchElementException if there are no more tokens in this
   *     tokenizer's string.
   *
   * @see #nextToken(String,String)
   * @since ostermillerutils 1.00.00
   */
  public String nextToken(String nontokenDelims){
    return nextToken(nontokenDelims, null);
  }

  /**
   * Similar to String.indexOf(int, String) but will look for
   * any character from string rather than the entire string.
   *
   * @param start index in text at which to begin the search
   * @return index of the first delimiter from the start index (inclusive), or -1
   *     if there are no more delimiters in the string
   *
   * @since ostermillerutils 1.00.00
   */
  private int indexOfNextDelimiter(int start){
    char c;
    int next;
    for (next = start; (c = text.charAt(next)) > maxDelimChar ||
      ((nontokenDelims == null || nontokenDelims.indexOf(c) == -1) &&
      (tokenDelims == null || tokenDelims.indexOf(c) == -1)); next++){
      if (next == strLength - 1){
        // we have reached the end of the string without
        // finding a delimiter
        return (-1);
      }
    }
    return next;
  }

  /**
   * Returns the same value as the <code>hasMoreTokens()</code> method. It exists
   * so that this class can implement the <code>Enumeration</code> interface.
   *
   * @return <code>true</code> if there are more tokens;
   *    <code>false</code> otherwise.
   *
   * @see java.util.Enumeration
   * @see #hasMoreTokens()
   * @since ostermillerutils 1.00.00
   */
  public boolean hasMoreElements(){
    return hasMoreTokens();
  }

  /**
   * Returns the same value as the <code>nextToken()</code> method, except that
   * its declared return value is <code>Object</code> rather than
   * <code>String</code>. It exists so that this class can implement the
   * <code>Enumeration</code> interface.
   *
   * @return the next token in the string.
   * @throws NoSuchElementException if there are no more tokens in this tokenizer's string.
   *
   * @see java.util.Enumeration
   * @see #nextToken()
   * @since ostermillerutils 1.00.00
   */
  public String nextElement(){
    return nextToken();
  }

  /**
   * Returns the same value as the <code>hasMoreTokens()</code> method. It exists
   * so that this class can implement the <code>Iterator</code> interface.
   *
   * @return <code>true</code> if there are more tokens;
   *     <code>false</code> otherwise.
   *
   * @see java.util.Iterator
   * @see #hasMoreTokens()
   * @since ostermillerutils 1.00.00
   */
  public boolean hasNext(){
    return hasMoreTokens();
  }

  /**
   * Returns the same value as the <code>nextToken()</code> method, except that
   * its declared return value is <code>Object</code> rather than
   * <code>String</code>. It exists so that this class can implement the
   * <code>Iterator</code> interface.
   *
   * @return the next token in the string.
   * @throws NoSuchElementException if there are no more tokens in this tokenizer's string.
   *
   * @see java.util.Iterator
   * @see #nextToken()
   * @since ostermillerutils 1.00.00
   */
  public String next(){
    return nextToken();
  }

  /**
   * This implementation always throws <code>UnsupportedOperationException</code>.
   * It exists so that this class can implement the <code>Iterator</code> interface.
   *
   * @throws UnsupportedOperationException always is thrown.
   *
   * @see java.util.Iterator
   * @since ostermillerutils 1.00.00
   */
  public void remove(){
    throw new UnsupportedOperationException();
  }

  /**
   * Set whether empty tokens should be returned from this point in
   * in the tokenizing process onward.
   * <P>
   * Empty tokens occur when two delimiters are next to each other
   * or a delimiter occurs at the beginning or end of a string. If
   * empty tokens are set to be returned, and a comma is the non token
   * delimiter, the following table shows how many tokens are in each
   * string.<br>
   * <table><tr><th>String<th><th>Number of tokens<th></tr>
   * <tr><td align=right>"one,two"<td><td>2 - normal case with no empty tokens.<td></tr>
   * <tr><td align=right>"one,,three"<td><td>3 including the empty token in the middle.<td></tr>
   * <tr><td align=right>"one,"<td><td>2 including the empty token at the end.<td></tr>
   * <tr><td align=right>",two"<td><td>2 including the empty token at the beginning.<td></tr>
   * <tr><td align=right>","<td><td>2 including the empty tokens at the beginning and the ends.<td></tr>
   * <tr><td align=right>""<td><td>1 - all strings will have at least one token if empty tokens are returned.<td></tr></table>
   *
   * @param returnEmptyTokens true iff empty tokens should be returned.
   *
   * @since ostermillerutils 1.00.00
   */
  public void setReturnEmptyTokens(boolean returnEmptyTokens){
    // this could effect the number of tokens
    tokenCount = -1;
    this.returnEmptyTokens = returnEmptyTokens;
  }

  /**
   * Get the the index of the character immediately
   * following the end of the last token.  This is the position at which this tokenizer will begin looking
   * for the next token when a <code>nextToken()</code> method is invoked.
   *
   * @return the current position or -1 if the entire string has been tokenized.
   *
   * @since ostermillerutils 1.00.00
   */
  public int getCurrentPosition(){
    return this.position;
  }

  /**
   * Retrieve all of the remaining tokens in a String array.
   * This method uses the options that are currently set for
   * the tokenizer and will advance the state of the tokenizer
   * such that <code>hasMoreTokens()</code> will return false.
   *
   * @return an array of tokens from this tokenizer.
   *
   * @since ostermillerutils 1.00.00
   */
  public String[] toArray(){
    String[] tokenArray = new String[countTokens()];
    for(int i=0; hasMoreTokens(); i++) {
      tokenArray[i] = nextToken();
    }
    return tokenArray;
  }

  /**
   * Retrieves the rest of the text as a single token.
   * After calling this method hasMoreTokens() will always return false.
   *
   * @return any part of the text that has not yet been tokenized.
   *
   * @since ostermillerutils 1.00.00
   */
  public String restOfText(){
    return nextToken(null, null);
  }

  /**
   * Returns the same value as nextToken() but does not alter
   * the internal state of the Tokenizer.  Subsequent calls
   * to peek() or a call to nextToken() will return the same
   * token again.
   *
   * @return the next token from this string tokenizer.
   * @throws NoSuchElementException if there are no more tokens in this tokenizer's string.
   *
   * @since ostermillerutils 1.00.00
   */
  public String peek(){
    // copy over state variables from the class to local
    // variables so that the state of this object can be
    // restored to the state that it was in before this
    // method was called.
    int savedPosition = position;
    boolean savedEmptyReturned = emptyReturned;
    int savedtokenCount = tokenCount;

    // get the next token
    String retval = nextToken();

    // restore the state
    position = savedPosition;
    emptyReturned = savedEmptyReturned;
    tokenCount = savedtokenCount;

    // return the nextToken;
    return(retval);
  }
}

   
    
    
    
  

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