string.java

gcc的组建

	  {
	    init (data, offset, count, "8859_1");
	  }
	catch (UnsupportedEncodingException x2)
	  {
	    // We know this can't happen.
	  }
      }
  }

  /**
   * Creates a new String using the byte array. Uses the encoding of the
   * platform's default charset, so the resulting string may be longer or
   * shorter than the byte array. For more decoding control, use
   * {@link java.nio.charset.CharsetDecoder}.  The behavior is not specified
   * if the decoder encounters invalid characters; this implementation throws
   * an Error.
   *
   * @param data byte array to copy
   * @throws NullPointerException if data is null
   * @throws Error if the decoding fails
   * @see #String(byte[], int, int)
   * @see #String(byte[], int, int, String)
   * @since 1.1
   */
  public String(byte[] data)
  {
    this(data, 0, data.length);
  }

  /**
   * Creates a new String using the character sequence represented by
   * the StringBuffer. Subsequent changes to buf do not affect the String.
   *
   * @param buffer StringBuffer to copy
   * @throws NullPointerException if buffer is null
   */
  public String(StringBuffer buffer)
  {
    synchronized (buffer)
      {
	// Share unless buffer is 3/4 empty.
	boolean should_copy = ((buffer.count << 2) < buffer.value.length);
	if (! should_copy)
	  buffer.shared = true;
	init (buffer.value, 0, buffer.count, ! should_copy);
      }
  }

  /**
   * Creates a new String using the character sequence represented by
   * the StringBuilder. Subsequent changes to buf do not affect the String.
   *
   * @param buffer StringBuilder to copy
   * @throws NullPointerException if buffer is null
   */
  public String(StringBuilder buffer)
  {
    this(buffer.value, 0, buffer.count);
  }

  /**
   * Special constructor which can share an array when safe to do so.
   *
   * @param data the characters to copy
   * @param offset the location to start from
   * @param count the number of characters to use
   * @param dont_copy true if the array is trusted, and need not be copied
   * @throws NullPointerException if chars is null
   * @throws StringIndexOutOfBoundsException if bounds check fails
   */
  String(char[] data, int offset, int count, boolean dont_copy)
  {
    init(data, offset, count, dont_copy);
  }

  // This is used by gnu.gcj.runtime.StringBuffer, so it must have
  // package-private protection.  It is accessed via CNI and so avoids
  // ordinary protection mechanisms.
  String(gnu.gcj.runtime.StringBuffer buffer)
  {
    // No need to synchronize or mark the buffer, since we know it is
    // 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 &lt; 0 || index &gt;= length()
   *         (while unspecified, this is a StringIndexOutOfBoundsException)
   */
  public native char charAt(int index);

  /**
   * Get the code point at the specified index.  This is like #charAt(int),
   * but if the character is the start of a surrogate pair, and the
   * following character completes the pair, then the corresponding
   * supplementary code point is returned.
   * @param index the index of the codepoint to get, starting at 0
   * @return the codepoint at the specified index
   * @throws IndexOutOfBoundsException if index is negative or &gt;= length()
   * @since 1.5
   */
  public synchronized int codePointAt(int index)
  {
    // Use the CharSequence overload as we get better range checking
    // this way.
    return Character.codePointAt(this, index);
  }

  /**
   * Get the code point before the specified index.  This is like
   * #codePointAt(int), but checks the characters at <code>index-1</code> and
   * <code>index-2</code> to see if they form a supplementary code point.
   * @param index the index just past the codepoint to get, starting at 0
   * @return the codepoint at the specified index
   * @throws IndexOutOfBoundsException if index is negative or &gt;= length()
   *         (while unspecified, this is a StringIndexOutOfBoundsException)
   * @since 1.5
   */
  public synchronized int codePointBefore(int index)
  {
    // Use the CharSequence overload as we get better range checking
    // this way.
    return Character.codePointBefore(this, 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 the given CharSequence to this String. This is true if
   * the CharSequence has the same content as this String at this
   * moment.
   *
   * @param seq the CharSequence to compare to
   * @return true if CharSequence has the same character sequence
   * @throws NullPointerException if the given CharSequence is null
   * @since 1.5
   */
  public native boolean contentEquals(CharSequence seq);

  /**
   * 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);