- * The size of the internal buffer defaults to 32 and it is resized - * in increments of 1024 chars. This behavior can be over-ridden by using the - * following two properties: - *
- *
- * There is a constructor that specified the initial buffer size and - * that is the preferred way to set that value because it it portable - * across all Java class library implementations. - *
- *
- * @author Aaron M. Renn (arenn@urbanophile.com)
- * @author Tom Tromey CharArrayWriter with
- * the default buffer size of 32 chars. If a different initial
- * buffer size is desired, see the constructor
- * CharArrayWriter(int size).
- */
- public CharArrayWriter ()
- {
- this (DEFAULT_INITIAL_BUFFER_SIZE);
- }
-
- /**
- * This method initializes a new CharArrayWriter with
- * a specified initial buffer size.
- *
- * @param size The initial buffer size in chars
- */
- public CharArrayWriter (int size)
- {
- super ();
- buf = new char[size];
- }
-
- /**
- * Closes the stream. This method is guaranteed not to free the contents
- * of the internal buffer, which can still be retrieved.
- */
- public void close ()
- {
- closed = true;
- }
-
- /**
- * This method flushes all buffered chars to the stream.
- */
- public void flush () throws IOException
- {
- synchronized (lock)
- {
- if (closed)
- throw new IOException ("Stream closed");
- }
- }
-
- /**
- * This method discards all of the chars that have been written to the
- * internal buffer so far by setting the count variable to
- * 0. The internal buffer remains at its currently allocated size.
- */
- public void reset ()
- {
- synchronized (lock)
- {
- count = 0;
- // Allow this to reopen the stream.
- // FIXME - what does the JDK do?
- closed = false;
- }
- }
-
- /**
- * This method returns the number of chars that have been written to
- * the buffer so far. This is the same as the value of the protected
- * count variable. If the reset method is
- * called, then this value is reset as well. Note that this method does
- * not return the length of the internal buffer, but only the number
- * of chars that have been written to it.
- *
- * @return The number of chars in the internal buffer
- *
- * @see reset
- */
- public int size ()
- {
- return count;
- }
-
- /**
- * This method returns a char array containing the chars that have been
- * written to this stream so far. This array is a copy of the valid
- * chars in the internal buffer and its length is equal to the number of
- * valid chars, not necessarily to the the length of the current
- * internal buffer. Note that since this method allocates a new array,
- * it should be used with caution when the internal buffer is very large.
- */
- public char[] toCharArray ()
- {
- synchronized (lock)
- {
- char[] nc = new char[count];
- System.arraycopy(buf, 0, nc, 0, count);
- return nc;
- }
- }
-
- /**
- * Returns the chars in the internal array as a String. The
- * chars in the buffer are converted to characters using the system default
- * encoding. There is an overloaded toString() method that
- * allows an application specified character encoding to be used.
- *
- * @return A String containing the data written to this
- * stream so far
- */
- public String toString ()
- {
- synchronized (lock)
- {
- return new String (buf, 0, count);
- }
- }
-
- /**
- * This method writes the writes the specified char into the internal
- * buffer.
- *
- * @param oneChar The char to be read passed as an int
- */
- public void write (int oneChar) throws IOException
- {
- synchronized (lock)
- {
- if (closed)
- throw new IOException ("Stream closed");
-
- resize (1);
- buf[count++] = (char) oneChar;
- }
- }
-
- /**
- * This method writes len chars from the passed in array
- * buf starting at index offset into that buffer
- *
- * @param buffer The char array to write data from
- * @param offset The index into the buffer to start writing data from
- * @param len The number of chars to write
- */
- public void write (char[] buffer, int offset, int len) throws IOException
- {
- synchronized (lock)
- {
- if (closed)
- throw new IOException ("Stream closed");
-
- if (len >= 0)
- resize (len);
- System.arraycopy(buffer, offset, buf, count, len);
- count += len;
- }
- }
-
- /**
- * This method writes len chars from the passed in
- * String buf starting at index
- * offset into the internal buffer.
- *
- * @param str The String to write data from
- * @param offset The index into the string to start writing data from
- * @param len The number of chars to write
- */
- public void write (String str, int offset, int len) throws IOException
- {
- synchronized (lock)
- {
- if (closed)
- throw new IOException ("Stream closed");
-
- if (len >= 0)
- resize (len);
- str.getChars(offset, offset + len, buf, count);
- count += len;
- }
- }
-
- /**
- * This method writes all the chars that have been written to this stream
- * from the internal buffer to the specified Writer.
- *
- * @param out The Writer to write to
- *
- * @exception IOException If an error occurs
- */
- public void writeTo (Writer out) throws IOException
- {
- synchronized (lock)
- {
- out.write(buf, 0, count);
- }
- }
-
- /**
- * This private method makes the buffer bigger when we run out of room
- * by allocating a larger buffer and copying the valid chars from the
- * old array into it. This is obviously slow and should be avoided by
- * application programmers by setting their initial buffer size big
- * enough to hold everything if possible.
- */
- private final void resize (int len)
- {
- if (count + len >= buf.length)
- {
- int newlen = buf.length * 2;
- if (count + len > newlen)
- newlen = count + len;
- char[] newbuf = new char[newlen];
- System.arraycopy(buf, 0, newbuf, 0, count);
- buf = newbuf;
- }
- }
-
- /**
- * The internal buffer where the data written is stored
- */
- protected char[] buf;
-
- /**
- * The number of chars that have been written to the buffer
- */
- protected int count;
-
- /**
- * True if the stream has been closed.
- */
- private boolean closed;
-}