checkError() method.
* Additionally, this stream can be designated as "autoflush" when
* created so that any writes are automatically flushed to the underlying
* output sink when the current line is terminated.
*
* This class converts char's into byte's using the system default encoding.
*
* @author Aaron M. Renn (arenn@urbanophile.com)
* @author Tom Tromey (tromey@cygnus.com)
*/
public class PrintStream extends FilterOutputStream
{
/* Notice the implementation is quite similar to OutputStreamWriter.
* This leads to some minor duplication, because neither inherits
* from the other, and we want to maximize performance. */
// Line separator string.
private static final char[] line_separator
= System.getProperty("line.separator").toCharArray();
UnicodeToBytes converter;
// Work buffer of characters for converter.
char[] work = new char[100];
// Work buffer of bytes where we temporarily keep converter output.
byte[] work_bytes = new byte[100];
/**
* This boolean indicates whether or not an error has ever occurred
* on this stream.
*/
private boolean error_occurred = false;
/**
* This is true if auto-flush is enabled,
* false otherwise
*/
private boolean auto_flush;
/**
* This method intializes a new PrintStream object to write
* to the specified output sink.
*
* @param out The OutputStream to write to.
*/
public PrintStream (OutputStream out)
{
this (out, false);
}
/**
* This method intializes a new PrintStream object to write
* to the specified output sink. This constructor also allows "auto-flush"
* functionality to be specified where the stream will be flushed after
* every print or println call, when the
* write methods with array arguments are called, or when a
* single new-line character is written.
*
*
* @param out The OutputStream to write to.
* @param auto_flush true to flush the stream after every
* line, false otherwise
*/
public PrintStream (OutputStream out, boolean auto_flush)
{
super (out);
converter = UnicodeToBytes.getDefaultEncoder();
this.auto_flush = auto_flush;
}
/**
* This method intializes a new PrintStream object to write
* to the specified output sink. This constructor also allows "auto-flush"
* functionality to be specified where the stream will be flushed after
* every print or println call, when the
* write methods with array arguments are called, or when a
* single new-line character is written.
*
*
* @param out The OutputStream to write to.
* @param auto_flush true to flush the stream after every
* line, false otherwise
* @param encoding The name of the character encoding to use for this
* object.
*/
public PrintStream (OutputStream out, boolean auto_flush, String encoding)
throws UnsupportedEncodingException
{
super (out);
converter = UnicodeToBytes.getEncoder (encoding);
this.auto_flush = auto_flush;
}
/**
* This method checks to see if an error has occurred on this stream. Note
* that once an error has occurred, this method will continue to report
* true forever for this stream. Before checking for an
* error condition, this method flushes the stream.
*
* @return true if an error has occurred,
* false otherwise
*/
public boolean checkError ()
{
flush ();
return error_occurred;
}
/**
* This method can be called by subclasses to indicate that an error
* has occurred and should be reported by checkError.
*/
protected void setError ()
{
error_occurred = true;
}
/**
* This method closes this stream and all underlying streams.
*/
public void close ()
{
try
{
converter.setFinished();
writeChars(new char[0], 0, 0);
flush();
out.close();
}
catch (InterruptedIOException iioe)
{
Thread.currentThread().interrupt();
}
catch (IOException e)
{
setError ();
}
}
/**
* This method flushes any buffered bytes to the underlying stream and
* then flushes that stream as well.
*/
public void flush ()
{
try
{
out.flush();
}
catch (InterruptedIOException iioe)
{
Thread.currentThread().interrupt();
}
catch (IOException e)
{
setError ();
}
}
private synchronized void print (String str, boolean println)
{
try
{
writeChars(str, 0, str.length());
if (println)
writeChars(line_separator, 0, line_separator.length);
if (auto_flush)
flush();
}
catch (InterruptedIOException iioe)
{
Thread.currentThread().interrupt();
}
catch (IOException e)
{
setError ();
}
}
private synchronized void print (char[] chars, int pos, int len,
boolean println)
{
try
{
writeChars(chars, pos, len);
if (println)
writeChars(line_separator, 0, line_separator.length);
if (auto_flush)
flush();
}
catch (InterruptedIOException iioe)
{
Thread.currentThread().interrupt();
}
catch (IOException e)
{
setError ();
}
}
private void writeChars(char[] buf, int offset, int count)
throws IOException
{
do
{
converter.setOutput(work_bytes, 0);
int converted = converter.write(buf, offset, count);
offset += converted;
count -= converted;
out.write(work_bytes, 0, converter.count);
}
while (count > 0 || converter.havePendingBytes());
}
private void writeChars(String str, int offset, int count)
throws IOException
{
do
{
converter.setOutput(work_bytes, 0);
int converted = converter.write(str, offset, count, work);
offset += converted;
count -= converted;
out.write(work_bytes, 0, converter.count);
}
while (count > 0 || converter.havePendingBytes());
}
/**
* This methods prints a boolean value to the stream. true
* values are printed as "true" and false values are printed
* as "false".
*
* @param bool The boolean value to print
*/
public void print (boolean bool)
{
print(String.valueOf(bool), false);
}
/**
* This method prints an integer to the stream. The value printed is
* determined using the String.valueOf() method.
*
* @param inum The int value to be printed
*/
public void print (int inum)
{
print(String.valueOf(inum), false);
}
/**
* This method prints a long to the stream. The value printed is
* determined using the String.valueOf() method.
*
* @param lnum The long value to be printed
*/
public void print (long lnum)
{
print(String.valueOf(lnum), false);
}
/**
* This method prints a float to the stream. The value printed is
* determined using the String.valueOf() method.
*
* @param fnum The float value to be printed
*/
public void print (float fnum)
{
print(String.valueOf(fnum), false);
}
/**
* This method prints a double to the stream. The value printed is
* determined using the String.valueOf() method.
*
* @param dnum The double value to be printed
*/
public void print (double dnum)
{
print(String.valueOf(dnum), false);
}
/**
* This method prints an Object to the stream. The actual
* value printed is determined by calling the String.valueOf()
* method.
*
* @param obj The Object to print.
*/
public void print (Object obj)
{
print(obj == null ? "null" : obj.toString(), false);
}
/**
* This method prints a String to the stream. The actual
* value printed depends on the system default encoding.
*
* @param str The String to print.
*/
public void print (String str)
{
print(str == null ? "null" : str, false);
}
/**
* This method prints a char to the stream. The actual value printed is
* determined by the character encoding in use.
*
* @param ch The char value to be printed
*/
public synchronized void print (char ch)
{
work[0] = ch;
print(work, 0, 1, false);
}
/**
* This method prints an array of characters to the stream. The actual
* value printed depends on the system default encoding.
*
* @param charArray The array of characters to print.
*/
public void print (char[] charArray)
{
print(charArray, 0, charArray.length, false);
}
/**
* This method prints a line separator sequence to the stream. The value
* printed is determined by the system property
true
* values are printed as "true" and false values are printed
* as "false".
*
* This method prints a line termination sequence after printing the value.
*
* @param bool The boolean value to print
*/
public void println (boolean bool)
{
print(String.valueOf(bool), true);
}
/**
* This method prints an integer to the stream. The value printed is
* determined using the String.valueOf() method.
*
* This method prints a line termination sequence after printing the value.
*
* @param inum The int value to be printed
*/
public void println (int inum)
{
print(String.valueOf(inum), true);
}
/**
* This method prints a long to the stream. The value printed is
* determined using the String.valueOf() method.
*
* This method prints a line termination sequence after printing the value.
*
* @param lnum The long value to be printed
*/
public void println (long lnum)
{
print(String.valueOf(lnum), true);
}
/**
* This method prints a float to the stream. The value printed is
* determined using the String.valueOf() method.
*
* This method prints a line termination sequence after printing the value.
*
* @param fnum The float value to be printed
*/
public void println (float fnum)
{
print(String.valueOf(fnum), true);
}
/**
* This method prints a double to the stream. The value printed is
* determined using the String.valueOf() method.
*
* This method prints a line termination sequence after printing the value.
*
* @param dnum The double value to be printed
*/
public void println (double dnum)
{
print(String.valueOf(dnum), true);
}
/**
* This method prints an Object to the stream. The actual
* value printed is determined by calling the String.valueOf()
* method.
*
* This method prints a line termination sequence after printing the value.
*
* @param obj The Object to print.
*/
public void println (Object obj)
{
print(obj == null ? "null" : obj.toString(), true);
}
/**
* This method prints a String to the stream. The actual
* value printed depends on the system default encoding.
*
* This method prints a line termination sequence after printing the value.
*
* @param str The String to print.
*/
public void println (String str)
{
print (str == null ? "null" : str, true);
}
/**
* This method prints a char to the stream. The actual value printed is
* determined by the character encoding in use.
*
* This method prints a line termination sequence after printing the value.
*
* @param ch The char value to be printed
*/
public synchronized void println (char ch)
{
work[0] = ch;
print(work, 0, 1, true);
}
/**
* This method prints an array of characters to the stream. The actual
* value printed depends on the system default encoding.
*
* This method prints a line termination sequence after printing the value.
*
* @param charArray The array of characters to print.
*/
public void println (char[] charArray)
{
print(charArray, 0, charArray.length, true);
}
/**
* This method writes a byte of data to the stream. If auto-flush is
* enabled, printing a newline character will cause the stream to be
* flushed after the character is written.
*
* @param oneByte The byte to be written
*/
public void write (int oneByte)
{
try
{
out.write (oneByte & 0xff);
if (auto_flush && (oneByte == '\n'))
flush ();
}
catch (InterruptedIOException iioe)
{
Thread.currentThread ().interrupt ();
}
catch (IOException e)
{
setError ();
}
}
/**
* This method writes len bytes from the specified array
* starting at index offset into the array.
*
* @param buffer The array of bytes to write
* @param offset The index into the array to start writing from
* @param len The number of bytes to write
*/
public void write (byte[] buffer, int offset, int len)
{
try
{
out.write (buffer, offset, len);
if (auto_flush)
flush ();
}
catch (InterruptedIOException iioe)
{
Thread.currentThread ().interrupt ();
}
catch (IOException e)
{
setError ();
}
}
} // class PrintStream