stringbuffer.java

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  }

  /** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
   *  Uses <code>String.valueOf()</code> to convert to
   *  <code>String</code>.
   *  @param offset the place to insert.
   *  @param inum the <code>int</code> to convert and insert.
   *  @return this <code>StringBuffer</code>.
   *  @exception IndexOutOfBoundsException if <code>offset</code> is out
   *             of range for this <code>StringBuffer</code>.
   *  @see java.lang.String#valueOf(int)
   */
  public StringBuffer insert (int offset, int inum)
  {
    return insert (offset, String.valueOf(inum));
  }

  /** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
   *  Uses <code>String.valueOf()</code> to convert to
   *  <code>String</code>.
   *  @param offset the place to insert.
   *  @param lnum the <code>long</code> to convert and insert.
   *  @return this <code>StringBuffer</code>.
   *  @exception IndexOutOfBoundsException if <code>offset</code> is out
   *             of range for this <code>StringBuffer</code>.
   *  @see java.lang.String#valueOf(long)
   */
  public StringBuffer insert (int offset, long lnum)
  {
    return insert (offset, String.valueOf(lnum));
  }

  /** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
   *  Uses <code>String.valueOf()</code> to convert to
   *  <code>String</code>.
   *  @param offset the place to insert.
   *  @param fnum the <code>float</code> to convert and insert.
   *  @return this <code>StringBuffer</code>.
   *  @exception IndexOutOfBoundsException if <code>offset</code> is out
   *             of range for this <code>StringBuffer</code>.
   *  @see java.lang.String#valueOf(float)
   */
  public StringBuffer insert (int offset, float fnum)
  {
    return insert (offset, String.valueOf(fnum));
  }

  /** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
   *  Uses <code>String.valueOf()</code> to convert to
   *  <code>String</code>.
   *  @param offset the place to insert.
   *  @param dnum the <code>double</code> to convert and insert.
   *  @return this <code>StringBuffer</code>.
   *  @exception IndexOutOfBoundsException if <code>offset</code> is out
   *             of range for this <code>StringBuffer</code>.
   *  @see java.lang.String#valueOf(double)
   */
  public StringBuffer insert (int offset, double dnum)
  {
    return insert (offset, String.valueOf(dnum));
  }

  /** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
   *  Uses <code>String.valueOf()</code> to convert to
   *  <code>String</code>.
   *  @param offset the place to insert.
   *  @param obj the <code>Object</code> to convert and insert.
   *  @return this <code>StringBuffer</code>.
   *  @exception IndexOutOfBoundsException if <code>offset</code> is out
   *             of range for this <code>StringBuffer</code>.
   *  @see java.lang.String#valueOf(java.lang.Object)
   */
  public StringBuffer insert (int offset, Object obj)
  {
    return insert (offset, String.valueOf(obj));
  }

  /** Insert the <code>String</code> argument into this <code>StringBuffer</code>.
   *  @param offset the place to insert.
   *  @param str the <code>String</code> to insert.
   *  @return this <code>StringBuffer</code>.
   *  @exception IndexOutOfBoundsException if <code>offset</code> is out
   *             of range for this <code>StringBuffer</code>.
   */
  public synchronized StringBuffer insert (int offset, String str)
  {
    if (offset < 0 || offset > count)
      throw new StringIndexOutOfBoundsException (offset);
    // Note that using `null' is from JDK 1.2.
    if (str == null)
      str = "null";
    int len = str.length();
    ensureCapacity_unsynchronized (count+len);
    System.arraycopy(value, offset, value, offset+len, count-offset);
    str.getChars(0, len, value, offset);
    count += len;
    return this;
  }

  /** Insert the <code>char[]</code> argument into this
   *  <code>StringBuffer</code>. 
   *  @param offset the place to insert.
   *  @param data the <code>char[]</code> to insert.
   *  @return this <code>StringBuffer</code>.
   *  @exception NullPointerException if <code>data</code> is
   *             <code>null</code>.
   *  @exception IndexOutOfBoundsException if <code>offset</code> is out
   *             of range for this <code>StringBuffer</code>.
   */
  public StringBuffer insert (int offset, char[] data)
  {
    // One could check if offset is invalid here instead of making sure that
    // data isn't null before dereferencing, but this works just as well.
    return insert (offset, data, 0, data == null ? 0 : data.length);
  }

  /** Insert the <code>char[]</code> argument into this
   *  <code>StringBuffer</code>.
   *  @param offset the place to insert.
   *  @param str the <code>char[]</code> to insert.
   *  @param str_offset the index in <code>str</code> to start inserting
   *         from.
   *  @param len the number of characters to insert.
   *  @return this <code>StringBuffer</code>.
   *  @exception NullPointerException if <code>str</code> is <code>null</code>.
   *  @exception IndexOutOfBoundsException if <code>offset</code> is out
   *             of range, for this <code>StringBuffer</code>, or if
   *             <code>str_offset</code> or <code>str_offset+len</code>
   *             are out of range for <code>str</code>.
   */
  public synchronized StringBuffer insert(int offset, char[] str,
					  int str_offset, int len)
  {
    if (offset < 0 || offset > count)
      throw new StringIndexOutOfBoundsException (offset);
    if (len < 0)
      throw new StringIndexOutOfBoundsException (len);
    if (str_offset < 0 || str_offset + len > str.length)
      throw new StringIndexOutOfBoundsException (str_offset);
    ensureCapacity_unsynchronized (count + len);
    System.arraycopy(value, offset, value, offset + len, count - offset);
    System.arraycopy(str, str_offset, value, offset, len);
    count += len;
    return this;
  }

  /** Get the length of the <code>String</code> this
   *  <code>StringBuffer</code> would create.  Not to be confused with the
   *  <em>capacity</em> of the <code>StringBuffer</code>.
   *  @return the length of this <code>StringBuffer</code>.
   *  @see #capacity()
   *  @see #setLength(int)
   */
  public int length ()
  {
    return count;
  }

  /** Replace characters between index <code>start</code> (inclusive) and 
   *  <code>end</code> (exclusive) with <code>str</code>. If <code>end</code> 
   *  is larger than the size of this StringBuffer, all characters after
   *  <code>start</code> are replaced.
   *  @param start the beginning index of characters to delete (inclusive).
   *  @param end the ending index of characters to delete (exclusive).
   *  @param str the new <code>String</code> to insert.
   *  @return this <code>StringBuffer</code>.
   */
  public synchronized StringBuffer replace (int start, int end, String str)
  {
    if (start < 0 || start > count || start > end)
      throw new StringIndexOutOfBoundsException (start);
  
    int len = str.length();
    // Calculate the difference in 'count' after the replace.
    int delta = len - ((end > count ? count : end) - start);
    ensureCapacity_unsynchronized (count + delta);
        
    if (delta != 0 && end < count)
      System.arraycopy(value, end, value, end + delta, count - end);
    
    str.getChars (0, len, value, start);    
    count += delta;    
    return this;    
  }

  /** Reverse the characters in this StringBuffer.
   *  @return this <code>StringBuffer</code>.
   */
  public synchronized StringBuffer reverse ()
  {
    // Call ensureCapacity to enforce copy-on-write.
    ensureCapacity_unsynchronized (count);
    for (int i = 0; i < count / 2; ++i)
      {
	char c = value[i];
	value[i] = value[count - i - 1];
	value[count - i - 1] = c;
      }
    return this;
  }

  /** Set the character at the specified index.
   *  @param index the index of the character to set starting at 0.
   *  @param ch the value to set that character to.
   *  @exception IndexOutOfBoundsException if the specified character
   *             index is not between 0 and length() - 1 (inclusive).
   */
  public synchronized void setCharAt (int index, char ch)
  {
    if (index < 0 || index >= count)
      throw new StringIndexOutOfBoundsException (index);
    // Call ensureCapacity to enforce copy-on-write.
    ensureCapacity_unsynchronized (count);
    value[index] = ch;
  }

  /** Set the length of this StringBuffer.
   *  <P>
   *  If the new length is greater than the current length, all the new
   *  characters are set to '\0'.
   *  <P>
   *  If the new length is less than the current length, the first
   *  <code>newLength</code> characters of the old array will be
   * @param newLength the new length
   * @exception IndexOutOfBoundsException if the new length is
   *            negative.
   * @see #length()
   */
  public synchronized void setLength (int newLength)
  {
    if (newLength < 0)
      throw new StringIndexOutOfBoundsException (newLength);

    ensureCapacity_unsynchronized (newLength);
    for (int i = count; i < newLength; ++i)
      value[i] = '\0';
    count = newLength;
  }

  /** Create a new StringBuffer with default capacity 16.
   *  @see JLS 20.13.1
   */
  public StringBuffer ()
  {
    this (DEFAULT_CAPACITY);
  }

  /** Create an empty <code>StringBuffer</code> with the specified initial capacity.
   *  @param capacity the initial capacity.
   */
  public StringBuffer (int capacity)
  {
    count = 0;
    value = new char[capacity];
    shared = false;
  }

  /** Create a new <code>StringBuffer</code> with the characters in the specified <code>String</code>.
   *  Initial capacity will be the size of the String plus 16.
   *  @param str the <code>String</code> to make a <code>StringBuffer</code> out of.
   *  @XXX optimize for sharing.
   */
  public StringBuffer (String str)
  {
    // The documentation is not clear, but experimentation with
    // other implementations indicates that StringBuffer(null)
    // should throw a NullPointerException.
    count = str.length();
    // JLS: The initial capacity of the string buffer is 16 plus the
    // length of the argument string.
    value = new char[count + DEFAULT_CAPACITY];
    str.getChars(0, count, value, 0);
    shared = false;
  }

  /**
   * Creates a substring of this StringBuffer, starting at a specified index
   * and ending at the end of this StringBuffer.
   *
   * @param beginIndex index to start substring (base 0)
   * 
   * @return new String which is a substring of this StringBuffer
   *
   * @exception StringIndexOutOfBoundsException 
   *   if (beginIndex < 0 || beginIndex > this.length())
   */
  public String substring (int beginIndex)
  {
    return substring (beginIndex, count);
  }

  /**
   * Creates a substring of this StringBuffer, starting at a specified index
   * and ending at one character before a specified index.
   *
   * @param beginIndex index to start substring (base 0)
   * @param endIndex index after the last character to be 
   *   copied into the substring
   * 
   * @return new String which is a substring of this StringBuffer
   *
   * @exception StringIndexOutOfBoundsException 
   *   if (beginIndex < 0 || endIndex > this.length() || beginIndex > endIndex)
   */
  public synchronized String substring (int beginIndex, int endIndex) 
  {
    if (beginIndex < 0 || endIndex > count || beginIndex > endIndex)
      throw new StringIndexOutOfBoundsException ();
    // FIXME: for libgcj it would be possible, and more efficient, to
    // enable sharing here.
    return new String (value, beginIndex, endIndex - beginIndex);
  }

  /**
   * Creates a substring of this StringBuffer, starting at a specified index
   * and ending at one character before a specified index.
   * <p>
   * To implement <code>CharSequence</code>.
   * Calls <code>substring(beginIndex, endIndex)</code>.
   *
   * @param beginIndex index to start substring (base 0)
   * @param endIndex index after the last character to be 
   *   copied into the substring
   * 
   * @return new String which is a substring of this StringBuffer
   *
   * @exception StringIndexOutOfBoundsException 
   *   if (beginIndex < 0 || endIndex > this.length() || beginIndex > endIndex)
   */
  public CharSequence subSequence (int beginIndex, int endIndex) 
  {
    return substring(beginIndex, endIndex);
  }


  /** Convert this <code>StringBuffer</code> to a <code>String</code>.
   *  @return the characters in this StringBuffer
   */
  public String toString ()
  {
    // Note: in libgcj this causes the StringBuffer to be shared.  In
    // Classpath it does not.
    return new String (this);
  }

  // Index of next available character.  Note that this has
  // permissions set this way so that String can get the value.
  int count;

  // The buffer.  Note that this has permissions set this way so that
  // String can get the value.
  char[] value;

  // True if we need to copy the buffer before writing to it again.
  // FIXME: JDK 1.2 doesn't specify this.  The new buffer-growing
  // semantics make this less useful in that case, too.  Note that
  // this has permissions set this way so that String can get the
  // value.
  boolean shared;

  static final long serialVersionUID = 3388685877147921107L;
  private final static int DEFAULT_CAPACITY = 16; // JLS 20.13.1
}