string.java

来自「Mac OS X 10.4.9 for x86 Source Code gcc」· Java 代码 · 共 1,258 行 · 第 1/3 页

    // only used once.
    init (buffer);
  }

  /**
   * Returns the number of characters contained in this String.
   *
   * @return the length of this String
   */
  public int length()
  {
    return count;
  }

  /**
   * Returns the character located at the specified index within this String.
   *
   * @param index position of character to return (base 0)
   * @return character located at position index
   * @throws IndexOutOfBoundsException if index < 0 || index >= length()
   *         (while unspecified, this is a StringIndexOutOfBoundsException)
   */
  public native char charAt(int index);

  /**
   * Copies characters from this String starting at a specified start index,
   * ending at a specified stop index, to a character array starting at
   * a specified destination begin index.
   *
   * @param srcBegin index to begin copying characters from this String
   * @param srcEnd index after the last character to be copied from this String
   * @param dst character array which this String is copied into
   * @param dstBegin index to start writing characters into dst
   * @throws NullPointerException if dst is null
   * @throws IndexOutOfBoundsException if any indices are out of bounds
   *         (while unspecified, source problems cause a
   *         StringIndexOutOfBoundsException, and dst problems cause an
   *         ArrayIndexOutOfBoundsException)
   */
  public native void getChars(int srcBegin, int srcEnd,
			      char[] dst, int dstBegin);

  /**
   * Copies the low byte of each character from this String starting at a
   * specified start index, ending at a specified stop index, to a byte array
   * starting at a specified destination begin index.
   *
   * @param srcBegin index to being copying characters from this String
   * @param srcEnd index after the last character to be copied from this String
   * @param dst byte array which each low byte of this String is copied into
   * @param dstBegin index to start writing characters into dst
   * @throws NullPointerException if dst is null and copy length is non-zero
   * @throws IndexOutOfBoundsException if any indices are out of bounds
   *         (while unspecified, source problems cause a
   *         StringIndexOutOfBoundsException, and dst problems cause an
   *         ArrayIndexOutOfBoundsException)
   * @see #getBytes()
   * @see #getBytes(String)
   * @deprecated use {@link #getBytes()}, which uses a char to byte encoder
   */
  public native void getBytes(int srcBegin, int srcEnd,
			      byte[] dst, int dstBegin);

  /**
   * Converts the Unicode characters in this String to a byte array. Uses the
   * specified encoding method, so the result may be longer or shorter than
   * the String. For more encoding control, use
   * {@link java.nio.charset.CharsetEncoder}, and for valid character sets,
   * see {@link java.nio.charset.Charset}. The behavior is not specified if
   * the encoder encounters a problem; this implementation returns null.
   *
   * @param enc encoding name
   * @return the resulting byte array, or null on a problem
   * @throws NullPointerException if enc is null
   * @throws UnsupportedEncodingException if encoding is not supported
   * @since 1.1
   */
  public native byte[] getBytes(String enc)
    throws UnsupportedEncodingException;

  /**
   * Converts the Unicode characters in this String to a byte array. Uses the
   * encoding of the platform's default charset, so the result may be longer
   * or shorter than the String. For more encoding control, use
   * {@link java.nio.charset.CharsetEncoder}.  The behavior is not specified if
   * the encoder encounters a problem; this implementation returns null.
   *
   * @return the resulting byte array, or null on a problem
   * @since 1.1
   */
  public byte[] getBytes()
  {
    try
      {
	return getBytes (System.getProperty("file.encoding", "8859_1"));
      }
    catch (UnsupportedEncodingException x)
      {
	// This probably shouldn't happen, but could if file.encoding
	// is somehow changed to a value we don't understand.
	try
	  {
	    return getBytes ("8859_1");
	  }
	catch (UnsupportedEncodingException x2)
	  {
	    // This really shouldn't happen, because the 8859_1
	    // encoding should always be available.
	    throw new InternalError ("couldn't find 8859_1 encoder");
	  }
      }
  }

  /**
   * Predicate which compares anObject to this. This is true only for Strings
   * with the same character sequence.
   *
   * @param anObject the object to compare
   * @return true if anObject is semantically equal to this
   * @see #compareTo(String)
   * @see #equalsIgnoreCase(String)
   */
  public native boolean equals(Object anObject);

  /**
   * Compares the given StringBuffer to this String. This is true if the
   * StringBuffer has the same content as this String at this moment.
   *
   * @param buffer the StringBuffer to compare to
   * @return true if StringBuffer has the same character sequence
   * @throws NullPointerException if the given StringBuffer is null
   * @since 1.4
   */
  public native boolean contentEquals(StringBuffer buffer);

  /**
   * Compares a String to this String, ignoring case. This does not handle
   * multi-character capitalization exceptions; instead the comparison is
   * made on a character-by-character basis, and is true if:<br><ul>
   * <li><code>c1 == c2</code></li>
   * <li><code>Character.toUpperCase(c1)
   *     == Character.toUpperCase(c2)</code></li>
   * <li><code>Character.toLowerCase(c1)
   *     == Character.toLowerCase(c2)</code></li>
   * </ul>
   *
   * @param anotherString String to compare to this String
   * @return true if anotherString is equal, ignoring case
   * @see #equals(Object)
   * @see Character#toUpperCase(char)
   * @see Character#toLowerCase(char)
   */
  public native boolean equalsIgnoreCase(String anotherString);

  /**
   * Compares this String and another String (case sensitive,
   * lexicographically). The result is less than 0 if this string sorts
   * before the other, 0 if they are equal, and greater than 0 otherwise.
   * After any common starting sequence is skipped, the result is
   * <code>this.charAt(k) - anotherString.charAt(k)</code> if both strings
   * have characters remaining, or
   * <code>this.length() - anotherString.length()</code> if one string is
   * a subsequence of the other.
   *
   * @param anotherString the String to compare against
   * @return the comparison
   * @throws NullPointerException if anotherString is null
   */
  public native int compareTo(String anotherString);

  /**
   * Behaves like <code>compareTo(java.lang.String)</code> unless the Object
   * is not a <code>String</code>.  Then it throws a
   * <code>ClassCastException</code>.
   *
   * @param o the object to compare against
   * @return the comparison
   * @throws NullPointerException if o is null
   * @throws ClassCastException if o is not a <code>String</code>
   * @since 1.2
   */
  public int compareTo(Object o)
  {
    return compareTo((String) o);
  }

  /**
   * Compares this String and another String (case insensitive). This
   * comparison is <em>similar</em> to equalsIgnoreCase, in that it ignores
   * locale and multi-characater capitalization, and compares characters
   * after performing
   * <code>Character.toLowerCase(Character.toUpperCase(c))</code> on each
   * character of the string. This is unsatisfactory for locale-based
   * comparison, in which case you should use {@link java.text.Collator}.
   *
   * @param str the string to compare against
   * @return the comparison
   * @see Collator#compare(String, String)
   * @since 1.2
   */
  public int compareToIgnoreCase(String str)
  {
    return this.toUpperCase().toLowerCase().compareTo(
     str.toUpperCase().toLowerCase());
  }  

  /**
   * Predicate which determines if this String matches another String
   * starting at a specified offset for each String and continuing
   * for a specified length. Indices out of bounds are harmless, and give
   * a false result.
   *
   * @param toffset index to start comparison at for this String
   * @param other String to compare region to this String
   * @param ooffset index to start comparison at for other
   * @param len number of characters to compare
   * @return true if regions match (case sensitive)
   * @throws NullPointerException if other is null
   */
  public native boolean regionMatches(int toffset,
				      String other, int ooffset, int len);

  /**
   * Predicate which determines if this String matches another String
   * starting at a specified offset for each String and continuing
   * for a specified length, optionally ignoring case. Indices out of bounds
   * are harmless, and give a false result. Case comparisons are based on
   * <code>Character.toLowerCase()</code> and
   * <code>Character.toUpperCase()</code>, not on multi-character
   * capitalization expansions.
   *
   * @param ignoreCase true if case should be ignored in comparision
   * @param toffset index to start comparison at for this String
   * @param other String to compare region to this String
   * @param oofset index to start comparison at for other
   * @param len number of characters to compare
   * @return true if regions match, false otherwise
   * @throws NullPointerException if other is null
   */
  public native boolean regionMatches(boolean ignoreCase, int toffset,
				      String other, int ooffset, int len);

  /**
   * Predicate which determines if this String contains the given prefix,
   * beginning comparison at toffset. The result is false if toffset is
   * negative or greater than this.length(), otherwise it is the same as
   * <code>this.subString(toffset).startsWith(prefix)</code>.
   *
   * @param prefix String to compare
   * @param toffset offset for this String where comparison starts
   * @return true if this String starts with prefix
   * @throws NullPointerException if prefix is null
   * @see #regionMatches(boolean, int, String, int, int)
   */
  public native boolean startsWith(String prefix, int toffset);

  /**
   * Predicate which determines if this String starts with a given prefix.
   * If the prefix is an empty String, true is returned.
   *
   * @param prefix String to compare
   * @return true if this String starts with the prefix
   * @throws NullPointerException if prefix is null
   * @see #startsWith(String, int)
   */
  public boolean startsWith(String prefix)
  {
    return startsWith (prefix, 0);
  }

  /**
   * Predicate which determines if this String ends with a given suffix.
   * If the suffix is an empty String, true is returned.
   *
   * @param suffix String to compare
   * @return true if this String ends with the suffix
   * @throws NullPointerException if suffix is null
   * @see #regionMatches(boolean, int, String, int, int)
   */
  public boolean endsWith(String suffix)
  {
    return regionMatches (this.count - suffix.count, suffix, 0, suffix.count);
  }

  /**
   * Computes the hashcode for this String. This is done with int arithmetic,
   * where ** represents exponentiation, by this formula:<br>
   * <code>s[0]*31**(n-1) + s[1]*31**(n-2) + ... + s[n-1]</code>.
   *
   * @return hashcode value of this String
   */
  public native int hashCode();

  /**
   * Finds the first instance of a character in this String.
   *
   * @param ch character to find
   * @return location (base 0) of the character, or -1 if not found
   */
  public int indexOf(int ch)
  {
    return indexOf(ch, 0);
  }

  /**
   * Finds the first instance of a character 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 ch character to find
   * @param fromIndex index to start the search
   * @return location (base 0) of the character, or -1 if not found
   */
  public native int indexOf(int ch, int fromIndex);

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

  /**
   * Finds the last instance of a character 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 ch character to find
   * @param fromIndex index to start the search
   * @return location (base 0) of the character, or -1 if not found
   */
  public native int lastIndexOf(int ch, int fromIndex);

  /**
   * Finds the first 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 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 native int indexOf(String str, int fromIndex);

  /**
   * 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)
  {
    if (fromIndex >= count)
      fromIndex = count - str.count;
    for (;; --fromIndex)
      {
	if (fromIndex < 0)
	  return -1;
	if (startsWith(str, fromIndex))
	  return fromIndex;
      }
  }

  /**
   * 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 begin index to start substring (inclusive, base 0)
   * @param end index to end at (exclusive)