string.java

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   * @return location (base 0) of the String, or -1 if not found
   * @throws NullPointerException if str is null
   */
  public int indexOf(String str)
  {
    return indexOf(str, 0);
  }

  /**
   * Finds the first instance of a String in this String, starting at
   * a given index.  If starting index is less than 0, the search
   * starts at the beginning of this String.  If the starting index
   * is greater than the length of this String, -1 is returned.
   *
   * @param str String to find
   * @param fromIndex index to start the search
   * @return location (base 0) of the String, or -1 if not found
   * @throws NullPointerException if str is null
   */
  public int indexOf(String str, int fromIndex)
  {
    if (fromIndex < 0)
      fromIndex = 0;
    int limit = count - str.count;
    for ( ; fromIndex <= limit; fromIndex++)
      if (regionMatches(fromIndex, str, 0, str.count))
        return fromIndex;
    return -1;
  }

  /**
   * Finds the last instance of a String in this String.
   *
   * @param str String to find
   * @return location (base 0) of the String, or -1 if not found
   * @throws NullPointerException if str is null
   */
  public int lastIndexOf(String str)
  {
    return lastIndexOf(str, count - str.count);
  }

  /**
   * Finds the last instance of a String in this String, starting at
   * a given index.  If starting index is greater than the maximum valid
   * index, then the search begins at the end of this String.  If the
   * starting index is less than zero, -1 is returned.
   *
   * @param str String to find
   * @param fromIndex index to start the search
   * @return location (base 0) of the String, or -1 if not found
   * @throws NullPointerException if str is null
   */
  public int lastIndexOf(String str, int fromIndex)
  {
    fromIndex = Math.min(fromIndex, count - str.count);
    for ( ; fromIndex >= 0; fromIndex--)
      if (regionMatches(fromIndex, str, 0, str.count))
        return fromIndex;
    return -1;
  }

  /**
   * Creates a substring of this String, starting at a specified index
   * and ending at the end of this String.
   *
   * @param begin index to start substring (base 0)
   * @return new String which is a substring of this String
   * @throws IndexOutOfBoundsException if begin &lt; 0 || begin &gt; length()
   *         (while unspecified, this is a StringIndexOutOfBoundsException)
   */
  public String substring(int begin)
  {
    return substring(begin, count);
  }

  /**
   * Creates a substring of this String, starting at a specified index
   * and ending at one character before a specified index.
   *
   * @param beginIndex index to start substring (inclusive, base 0)
   * @param endIndex index to end at (exclusive)
   * @return new String which is a substring of this String
   * @throws IndexOutOfBoundsException if begin &lt; 0 || end &gt; length()
   *         || begin &gt; end (while unspecified, this is a
   *         StringIndexOutOfBoundsException)
   */
  public String substring(int beginIndex, int endIndex)
  {
    if (beginIndex < 0 || endIndex > count || beginIndex > endIndex)
      throw new StringIndexOutOfBoundsException();
    if (beginIndex == 0 && endIndex == count)
      return this;
    int len = endIndex - beginIndex;
    // Package constructor avoids an array copy.
    return new String(value, beginIndex + offset, len,
                      (len << 2) >= value.length);
  }

  /**
   * Creates a substring of this String, starting at a specified index
   * and ending at one character before a specified index. This behaves like
   * <code>substring(begin, end)</code>.
   *
   * @param begin index to start substring (inclusive, base 0)
   * @param end index to end at (exclusive)
   * @return new String which is a substring of this String
   * @throws IndexOutOfBoundsException if begin &lt; 0 || end &gt; length()
   *         || begin &gt; end
   * @since 1.4
   */
  public CharSequence subSequence(int begin, int end)
  {
    return substring(begin, end);
  }

  /**
   * Concatenates a String to this String. This results in a new string unless
   * one of the two originals is "".
   *
   * @param str String to append to this String
   * @return newly concatenated String
   * @throws NullPointerException if str is null
   */
  public String concat(String str)
  {
    if (str.count == 0)
      return this;
    if (count == 0)
      return str;
    char[] newStr = new char[count + str.count];
    VMSystem.arraycopy(value, offset, newStr, 0, count);
    VMSystem.arraycopy(str.value, str.offset, newStr, count, str.count);
    // Package constructor avoids an array copy.
    return new String(newStr, 0, newStr.length, true);
  }

  /**
   * Replaces every instance of a character in this String with a new
   * character. If no replacements occur, this is returned.
   *
   * @param oldChar the old character to replace
   * @param newChar the new character
   * @return new String with all instances of oldChar replaced with newChar
   */
  public String replace(char oldChar, char newChar)
  {
    if (oldChar == newChar)
      return this;
    int i = count;
    int x = offset - 1;
    while (--i >= 0)
      if (value[++x] == oldChar)
        break;
    if (i < 0)
      return this;
    char[] newStr = (char[]) value.clone();
    newStr[x] = newChar;
    while (--i >= 0)
      if (value[++x] == oldChar)
        newStr[x] = newChar;
    // Package constructor avoids an array copy.
    return new String(newStr, offset, count, true);
  }

  /**
   * Test if this String matches a regular expression. This is shorthand for
   * <code>{@link Pattern}.matches(regex, this)</code>.
   *
   * @param regex the pattern to match
   * @return true if the pattern matches
   * @throws NullPointerException if regex is null
   * @throws PatternSyntaxException if regex is invalid
   * @see Pattern#matches(String, CharSequence)
   * @since 1.4
   */
  public boolean matches(String regex)
  {
    return Pattern.matches(regex, this);
  }

  /**
   * Replaces the first substring match of the regular expression with a
   * given replacement. This is shorthand for <code>{@link Pattern}
   *   .compile(regex).matcher(this).replaceFirst(replacement)</code>.
   *
   * @param regex the pattern to match
   * @param replacement the replacement string
   * @return the modified string
   * @throws NullPointerException if regex or replacement is null
   * @throws PatternSyntaxException if regex is invalid
   * @see #replaceAll(String, String)
   * @see Pattern#compile(String)
   * @see Pattern#matcher(CharSequence)
   * @see Matcher#replaceFirst(String)
   * @since 1.4
   */
  public String replaceFirst(String regex, String replacement)
  {
    return Pattern.compile(regex).matcher(this).replaceFirst(replacement);
  }

  /**
   * Replaces all matching substrings of the regular expression with a
   * given replacement. This is shorthand for <code>{@link Pattern}
   *   .compile(regex).matcher(this).replaceAll(replacement)</code>.
   *
   * @param regex the pattern to match
   * @param replacement the replacement string
   * @return the modified string
   * @throws NullPointerException if regex or replacement is null
   * @throws PatternSyntaxException if regex is invalid
   * @see #replaceFirst(String, String)
   * @see Pattern#compile(String)
   * @see Pattern#matcher(CharSequence)
   * @see Matcher#replaceAll(String)
   * @since 1.4
   */
  public String replaceAll(String regex, String replacement)
  {
    return Pattern.compile(regex).matcher(this).replaceAll(replacement);
  }

  /**
   * Split this string around the matches of a regular expression. Each
   * element of the returned array is the largest block of characters not
   * terminated by the regular expression, in the order the matches are found.
   *
   * <p>The limit affects the length of the array. If it is positive, the
   * array will contain at most n elements (n - 1 pattern matches). If
   * negative, the array length is unlimited, but there can be trailing empty
   * entries. if 0, the array length is unlimited, and trailing empty entries
   * are discarded.
   *
   * <p>For example, splitting "boo:and:foo" yields:<br>
   * <table border=0>
   * <th><td>Regex</td> <td>Limit</td> <td>Result</td></th>
   * <tr><td>":"</td>   <td>2</td>  <td>{ "boo", "and:foo" }</td></tr>
   * <tr><td>":"</td>   <td>t</td>  <td>{ "boo", "and", "foo" }</td></tr>
   * <tr><td>":"</td>   <td>-2</td> <td>{ "boo", "and", "foo" }</td></tr>
   * <tr><td>"o"</td>   <td>5</td>  <td>{ "b", "", ":and:f", "", "" }</td></tr>
   * <tr><td>"o"</td>   <td>-2</td> <td>{ "b", "", ":and:f", "", "" }</td></tr>
   * <tr><td>"o"</td>   <td>0</td>  <td>{ "b", "", ":and:f" }</td></tr>
   * </table>
   *
   * <p>This is shorthand for
   * <code>{@link Pattern}.compile(regex).split(this, limit)</code>.
   *
   * @param regex the pattern to match
   * @param limit the limit threshold
   * @return the array of split strings
   * @throws NullPointerException if regex or replacement is null
   * @throws PatternSyntaxException if regex is invalid
   * @see Pattern#compile(String)
   * @see Pattern#split(CharSequence, int)
   * @since 1.4
   */
  public String[] split(String regex, int limit)
  {
    return Pattern.compile(regex).split(this, limit);
  }

  /**
   * Split this string around the matches of a regular expression. Each
   * element of the returned array is the largest block of characters not
   * terminated by the regular expression, in the order the matches are found.
   * The array length is unlimited, and trailing empty entries are discarded,
   * as though calling <code>split(regex, 0)</code>.
   *
   * @param regex the pattern to match
   * @return the array of split strings
   * @throws NullPointerException if regex or replacement is null
   * @throws PatternSyntaxException if regex is invalid
   * @see #split(String, int)
   * @see Pattern#compile(String)
   * @see Pattern#split(CharSequence, int)
   * @since 1.4
   */
  public String[] split(String regex)
  {
    return Pattern.compile(regex).split(this, 0);
  }

  /**
   * Lowercases this String according to a particular locale. This uses
   * Unicode's special case mappings, as applied to the given Locale, so the
   * resulting string may be a different length.
   *
   * @param loc locale to use
   * @return new lowercased String, or this if no characters were lowercased
   * @throws NullPointerException if loc is null
   * @see #toUpperCase(Locale)
   * @since 1.1
   */
  public String toLowerCase(Locale loc)
  {
    // First, see if the current string is already lower case.
    boolean turkish = "tr".equals(loc.getLanguage());
    int i = count;
    int x = offset - 1;
    while (--i >= 0)
      {
        char ch = value[++x];
        if ((turkish && ch == '\u0049')
            || ch != Character.toLowerCase(ch))
          break;
      }
    if (i < 0)
      return this;

    // Now we perform the conversion. Fortunately, there are no multi-character
    // lowercase expansions in Unicode 3.0.0.
    char[] newStr = (char[]) value.clone();
    do
      {
        char ch = value[x];
        // Hardcoded special case.
        newStr[x++] = (turkish && ch == '\u0049') ? '\u0131'
          : Character.toLowerCase(ch);
      }
    while (--i >= 0);
    // Package constructor avoids an array copy.
    return new String(newStr, offset, count, true);
  }

  /**
   * Lowercases this String. This uses Unicode's special case mappings, as
   * applied to the platform's default Locale, so the resulting string may
   * be a different length.
   *
   * @return new lowercased String, or this if no characters were lowercased
   * @see #toLowerCase(Locale)
   * @see #toUpperCase()
   */
  public String toLowerCase()
  {
    return toLowerCase(Locale.getDefault());
  }

  /**
   * Uppercases this String according to a particular locale. This uses
   * Unicode's special case mappings, as applied to the given Locale, so the
   * resulting string may be a different length.
   *
   * @param loc locale to use
   * @return new uppercased String, or this if no characters were uppercased
   * @throws NullPointerException if loc is null
   * @see #toLowerCase(Locale)
   * @since 1.1
   */
  public String toUpperCase(Locale loc)
  {
    // First, see how many characters we have to grow by, as well as if the
    // current string is already upper case.
    boolean turkish = "tr".equals(loc.getLanguage());
    int expand = 0;
    boolean unchanged = true;
    int i = count;
    int x = i + offset;
    while (--i >= 0)
      {
        char ch = value[--x];
        expand += upperCaseExpansion(ch);
        unchanged = (unchanged && expand == 0
                     && ! (turkish && ch == '\u0069')
                     && ch == Character.toUpperCase(ch));
      }
    if (unchanged)
      return this;

    // Now we perform the conversion.
    i = count;
    if (expand == 0)
      {
        char[] newStr = (char[]) value.clone();
        while (--i >= 0)
          {
            char ch = value[x];
            // Hardcoded special case.
            newStr[x++] = (turkish && ch == '\u0069') ? '\u0130'
              : Character.toUpperCase(ch);
          }
        // Package constructor avoids an array copy.
        return new String(newStr, offset, count, true);
      }

    // Expansion is necessary.