* 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;
}