PrintStream adds functionality to another output stream,
* namely the ability to print representations of various data values
* conveniently. Two other features are provided as well. Unlike other output
* streams, a PrintStream never throws an
* IOException; instead, exceptional situations merely set an
* internal flag that can be tested via the checkError method.
* Optionally, a PrintStream can be created so as to flush
* automatically; this means that the flush method is
* automatically invoked after a byte array is written, one of the
* println methods is invoked, or a newline character or byte
* ('\n') is written.
*
* All characters printed by a PrintStream are converted into
* bytes using the platform's default character encoding. The {@link
* PrintWriter} class should be used in situations that require writing
* characters rather than bytes.
*
* @version 1.25, 03/01/23
* @author Frank Yellin
* @author Mark Reinhold
* @since JDK1.0
*/
public class PrintStream extends FilterOutputStream {
private boolean autoFlush = false;
private boolean trouble = false;
/**
* Track both the text- and character-output streams, so that their buffers
* can be flushed without flushing the entire stream.
*/
//KML private BufferedWriter textOut;
//KML private OutputStreamWriter charOut;
/**
* Create a new print stream. This stream will not flush automatically.
*
* @param out The output stream to which values and objects will be
* printed
*
* @see java.io.PrintWriter#PrintWriter(java.io.OutputStream)
*/
public PrintStream(OutputStream out) {
this(out, false);
}
/* Initialization is factored into a private constructor (note the swapped
* parameters so that this one isn't confused with the public one) and a
* separate init method so that the following two public constructors can
* share code. We use a separate init method so that the constructor that
* takes an encoding will throw an NPE for a null stream before it throws
* an UnsupportedEncodingException for an unsupported encoding.
*/
private PrintStream(boolean autoFlush, OutputStream out)
{
super(out);
if (out == null)
throw new NullPointerException("Null output stream");
this.autoFlush = autoFlush;
}
private void init(OutputStreamWriter osw) {
this.charOut = osw;
this.textOut = new BufferedWriter(osw);
}
/**
* Create a new print stream.
*
* @param out The output stream to which values and objects will be
* printed
* @param autoFlush A boolean; if true, the output buffer will be flushed
* whenever a byte array is written, one of the
* println methods is invoked, or a newline
* character or byte ('\n') is written
*
* @see java.io.PrintWriter#PrintWriter(java.io.OutputStream, boolean)
*/
public PrintStream(OutputStream out, boolean autoFlush) {
this(autoFlush, out);
init(new OutputStreamWriter(this));
}
/**
* Create a new print stream.
*
* @param out The output stream to which values and objects will be
* printed
* @param autoFlush A boolean; if true, the output buffer will be flushed
* whenever a byte array is written, one of the
* println methods is invoked, or a newline
* character or byte ('\n') is written
* @param encoding The name of a supported
*
* character encoding
*
* @exception UnsupportedEncodingException
* If the named encoding is not supported
*/
public PrintStream(OutputStream out, boolean autoFlush, String encoding)
throws UnsupportedEncodingException
{
this(autoFlush, out);
init(new OutputStreamWriter(this, encoding));
}
/** Check to make sure that the stream has not been closed */
private void ensureOpen() throws IOException {
if (out == null)
throw new IOException("Stream closed");
}
/**
* Flush the stream. This is done by writing any buffered output bytes to
* the underlying output stream and then flushing that stream.
*
* @see java.io.OutputStream#flush()
*/
public void flush() {
synchronized (this) {
try {
ensureOpen();
out.flush();
}
catch (IOException x) {
trouble = true;
}
}
}
private boolean closing = false; /* To avoid recursive closing */
/**
* Close the stream. This is done by flushing the stream and then closing
* the underlying output stream.
*
* @see java.io.OutputStream#close()
*/
public void close() {
synchronized (this) {
if (! closing) {
closing = true;
try {
textOut.close();
out.close();
}
catch (IOException x) {
trouble = true;
}
textOut = null;
charOut = null;
out = null;
}
}
}
/**
* Flush the stream and check its error state. The internal error state
* is set to true when the underlying output stream throws an
* IOException other than InterruptedIOException,
* and when the setError method is invoked. If an operation
* on the underlying output stream throws an
* InterruptedIOException, then the PrintStream
* converts the exception back into an interrupt by doing:
*
* Thread.currentThread().interrupt();
*
* or the equivalent.
*
* @return True if and only if this stream has encountered an
* IOException other than
* InterruptedIOException, or the
* setError method has been invoked
*/
public boolean checkError() {
if (out != null)
flush();
return trouble;
}
/**
* Set the error state of the stream to true.
*
* @since JDK1.1
*/
protected void setError() {
trouble = true;
}
/*
* Exception-catching, synchronized output operations,
* which also implement the write() methods of OutputStream
*/
/**
* Write the specified byte to this stream. If the byte is a newline and
* automatic flushing is enabled then the flush method will be
* invoked.
*
* Note that the byte is written as given; to write a character that
* will be translated according to the platform's default character
* encoding, use the print(char) or println(char)
* methods.
*
* @param b The byte to be written
* @see #print(char)
* @see #println(char)
*/
public void write(int b) {
try {
synchronized (this) {
ensureOpen();
out.write(b);
if ((b == '\n') && autoFlush)
out.flush();
}
}
catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
}
catch (IOException x) {
trouble = true;
}
}
/**
* Write len bytes from the specified byte array starting at
* offset off to this stream. If automatic flushing is
* enabled then the flush method will be invoked.
*
*
Note that the bytes will be written as given; to write characters
* that will be translated according to the platform's default character
* encoding, use the print(char) or println(char)
* methods.
*
* @param buf A byte array
* @param off Offset from which to start taking bytes
* @param len Number of bytes to write
*/
public void write(byte buf[], int off, int len) {
try {
synchronized (this) {
ensureOpen();
out.write(buf, off, len);
if (autoFlush)
out.flush();
}
}
catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
}
catch (IOException x) {
trouble = true;
}
}
/*
* The following private methods on the text- and character-output streams
* always flush the stream buffers, so that writes to the underlying byte
* stream occur as promptly as with the original PrintStream.
*/
private void write(char buf[]) {
try {
synchronized (this) {
ensureOpen();
textOut.write(buf);
textOut.flushBuffer();
charOut.flushBuffer();
if (autoFlush) {
for (int i = 0; i < buf.length; i++)
if (buf[i] == '\n')
out.flush();
}
}
}
catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
}
catch (IOException x) {
trouble = true;
}
}
private void write(String s) {
try {
synchronized (this) {
ensureOpen();
textOut.write(s);
textOut.flushBuffer();
charOut.flushBuffer();
if (autoFlush && (s.indexOf('\n') >= 0))
out.flush();
}
}
catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
}
catch (IOException x) {
trouble = true;
}
}
private void newLine() {
try {
synchronized (this) {
ensureOpen();
textOut.newLine();
textOut.flushBuffer();
charOut.flushBuffer();
if (autoFlush)
out.flush();
}
}
catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
}
catch (IOException x) {
trouble = true;
}
}
/* Methods that do not terminate lines */
/**
* Print a boolean value. The string produced by {@link
* java.lang.String#valueOf(boolean)} is translated into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the
* {@link #write(int)} method.
*
* @param b The boolean to be printed
*/
public void print(boolean b) {
write(b ? "true" : "false");
}
/**
* Print a character. The character is translated into one or more bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the
* {@link #write(int)} method.
*
* @param c The char to be printed
*/
public void print(char c) {
write(String.valueOf(c));
}
/**
* Print an integer. The string produced by {@link
* java.lang.String#valueOf(int)} is translated into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the
* {@link #write(int)} method.
*
* @param i The int to be printed
* @see java.lang.Integer#toString(int)
*/
public void print(int i) {
write(String.valueOf(i));
}
/**
* Print a long integer. The string produced by {@link
* java.lang.String#valueOf(long)} is translated into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the
* {@link #write(int)} method.
*
* @param l The long to be printed
* @see java.lang.Long#toString(long)
*/
public void print(long l) {
write(String.valueOf(l));
}
/**
* Print a floating-point number. The string produced by {@link
* java.lang.String#valueOf(float)} is translated into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the
* {@link #write(int)} method.
*
* @param f The float to be printed
* @see java.lang.Float#toString(float)
*/
public void print(float f) {
write(String.valueOf(f));
}
/**
* Print a double-precision floating-point number. The string produced by
* {@link java.lang.String#valueOf(double)} is translated into
* bytes according to the platform's default character encoding, and these
* bytes are written in exactly the manner of the {@link
* #write(int)} method.
*
* @param d The double to be printed
* @see java.lang.Double#toString(double)
*/
public void print(double d) {
write(String.valueOf(d));
}
/**
* Print an array of characters. The characters are converted into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the
* {@link #write(int)} method.
*
* @param s The array of chars to be printed
*
* @throws NullPointerException If s is null
*/
public void print(char s[]) {
write(s);
}
/**
* Print a string. If the argument is null then the string
* "null" is printed. Otherwise, the string's characters are
* converted into bytes according to the platform's default character
* encoding, and these bytes are written in exactly the manner of the
* {@link #write(int)} method.
*
* @param s The String to be printed
*/
public void print(String s) {
if (s == null) {
s = "null";
}
write(s);
}
/**
* Print an object. The string produced by the {@link
* java.lang.String#valueOf(Object)} method is translated into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the
* {@link #write(int)} method.
*
* @param obj The Object to be printed
* @see java.lang.Object#toString()
*/
public void print(Object obj) {
write(String.valueOf(obj));
}
/* Methods that do terminate lines */
/**
* Terminate the current line by writing the line separator string. The
* line separator string is defined by the system property
* line.separator, and is not necessarily a single newline
* character ('\n').
*/
public void println() {
newLine();
}
/**
* Print a boolean and then terminate the line. This method behaves as
* though it invokes {@link #print(boolean)} and then
* {@link #println()}.
*
* @param x The boolean to be printed
*/
public void println(boolean x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print a character and then terminate the line. This method behaves as
* though it invokes {@link #print(char)} and then
* {@link #println()}.
*
* @param x The char to be printed.
*/
public void println(char x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print an integer and then terminate the line. This method behaves as
* though it invokes {@link #print(int)} and then
* {@link #println()}.
*
* @param x The int to be printed.
*/
public void println(int x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print a long and then terminate the line. This method behaves as
* though it invokes {@link #print(long)} and then
* {@link #println()}.
*
* @param x a The long to be printed.
*/
public void println(long x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print a float and then terminate the line. This method behaves as
* though it invokes {@link #print(float)} and then
* {@link #println()}.
*
* @param x The float to be printed.
*/
public void println(float x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print a double and then terminate the line. This method behaves as
* though it invokes {@link #print(double)} and then
* {@link #println()}.
*
* @param x The double to be printed.
*/
public void println(double x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print an array of characters and then terminate the line. This method
* behaves as though it invokes {@link #print(char[])} and
* then {@link #println()}.
*
* @param x an array of chars to print.
*/
public void println(char x[]) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print a String and then terminate the line. This method behaves as
* though it invokes {@link #print(String)} and then
* {@link #println()}.
*
* @param x The String to be printed.
*/
public void println(String x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print an Object and then terminate the line. This method behaves as
* though it invokes {@link #print(Object)} and then
* {@link #println()}.
*
* @param x The Object to be printed.
*/
public void println(Object x) {
synchronized (this) {
print(x);
newLine();
}
}
}