* 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 (tromey@cygnus.com)
*/
public class CharArrayWriter extends Writer
{
/**
* The default initial buffer size
*/
private static final int DEFAULT_INITIAL_BUFFER_SIZE = 32;
/**
* This method initializes a new 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 ()
{
}
/**
* This method flushes all buffered chars to the stream.
*/
public void flush ()
{
}
/**
* 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;
}
}
/**
* 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)
{
synchronized (lock)
{
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)
{
synchronized (lock)
{
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)
{
synchronized (lock)
{
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);
}
}
/**
* Appends the Unicode character, c, to the output stream
* underlying this writer. This is equivalent to write(c).
*
* @param c the character to append.
* @return a reference to this object.
* @since 1.5
*/
public CharArrayWriter append(char c)
{
write(c);
return this;
}
/**
* Appends the specified sequence of Unicode characters to the
* output stream underlying this writer. This is equivalent to
* appending the results of calling toString() on the
* character sequence. As a result, the entire sequence may not be
* appended, as it depends on the implementation of
* toString() provided by the
* CharSequence. For example, if the character
* sequence is wrapped around an input buffer, the results will
* depend on the current position and length of that buffer.
*
* @param cs the character sequence to append. If seq is null,
* then the string "null" (the string representation of null)
* is appended.
* @return a reference to this object.
* @since 1.5
*/
public CharArrayWriter append(CharSequence cs)
{
try
{
write(cs == null ? "null" : cs.toString());
}
catch (IOException _)
{
// Can't happen.
}
return this;
}
/**
* Appends the specified subsequence of Unicode characters to the
* output stream underlying this writer, starting and ending at the
* specified positions within the sequence. The behaviour of this
* method matches the behaviour of writing the result of
* append(seq.subSequence(start,end)) when the sequence
* is not null.
*
* @param cs the character sequence to append. If seq is null,
* then the string "null" (the string representation of null)
* is appended.
* @param start the index of the first Unicode character to use from
* the sequence.
* @param end the index of the last Unicode character to use from the
* sequence.
* @return a reference to this object.
* @throws IndexOutOfBoundsException if either of the indices are negative,
* the start index occurs after the end index, or the end index is
* beyond the end of the sequence.
* @since 1.5
*/
public CharArrayWriter append(CharSequence cs, int start, int end)
{
try
{
write(cs == null ? "null" : cs.subSequence(start, end).toString());
}
catch (IOException _)
{
// Can't happen.
}
return this;
}
/**
* 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 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;
}