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PrintStream.java
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1998-09-22
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/*
* @(#)PrintStream.java 1.11 98/07/01
*
* Copyright 1995-1998 by Sun Microsystems, Inc.,
* 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
* All rights reserved.
*
* This software is the confidential and proprietary information
* of Sun Microsystems, Inc. ("Confidential Information"). You
* shall not disclose such Confidential Information and shall use
* it only in accordance with the terms of the license agreement
* you entered into with Sun.
*/
package java.io;
/**
* Print values and objects to an output stream, using the platform's default
* character encoding to convert characters into bytes.
*
* <p> If automatic flushing is enabled at creation time, then the stream will
* be flushed each time a line is terminated or a newline character is written.
*
* <p> Methods in this class never throw I/O exceptions. Client code may
* inquire as to whether any errors have occurred by invoking the
* <code>checkError</code> method.
*
* <p><b>Note:</b> <i>This class is provided primarily for use in debugging,
* and for compatibility with existing code; new code should use the
* PrintWriter class.</i>
*
* @see java.io.PrintWriter
*
* @version 1.11, 07/01/98
* @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.
*/
private BufferedWriter textOut;
private OutputStreamWriter charOut;
/**
* Create a new print stream.
*
* @deprecated As of JDK 1.1, the preferred way to print text is
* via the PrintWriter class. Consider replacing code of the<br>
* form <code> PrintStream p = new PrintStream(out);</code><br>
* with <code> PrintWriter p = new PrintWriter(out);</code>
*
* @see java.io.PrintWriter#PrintWriter(java.io.OutputStream)
*
* @param out The output stream to which values and objects will be
* printed
*/
public PrintStream(OutputStream out) {
this(out, false);
}
/**
* Create a new PrintStream.
*
* @deprecated As of JDK 1.1, the preferred way to print text is
* via the PrintWriter class. Consider replacing code of the<br>
* form <code> PrintStream p = new PrintStream(out, autoFlush);</code><br>
* with <code> PrintWriter p = new PrintWriter(out, autoFlush);</code>
*
* @see java.io.PrintWriter#PrintWriter(java.io.OutputStream, boolean)
*
* @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 line is terminated or a newline character
* (<code>'\n'</code>) is written
*/
public PrintStream(OutputStream out, boolean autoFlush) {
super(out);
this.autoFlush = autoFlush;
this.charOut = new OutputStreamWriter(this);
this.textOut = new BufferedWriter(this.charOut);
}
/** 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. Errors are cumulative;
* once the stream encounters an error, this routine will continue to
* return true on all successive calls.
*
* @return True if the print stream has encountered an error, either on the
* underlying output stream or during a format conversion, otherwise false.
*/
public boolean checkError() {
if (out != null)
flush();
return trouble;
}
/** Indicate that an error has occurred. */
protected void setError() {
trouble = true;
}
/*
* Exception-catching, synchronized output operations,
* which also implement the write() methods of OutputStream
*/
/**
* Write a byte, blocking if necessary. If the character is a newline and
* automatic flushing is enabled, the stream's <code>flush</code> method
* will be called.
*
* <p> 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 <code>print(char)</code> or <code>println(char)</code>
* 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 a portion of a byte array, blocking if necessary.
*
* @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. If the given value is true, then the string
* <code>"true"</code> is written to the underlying output stream;
* otherwise, the string <code>"false"</code> is written.
*
* @param b The <code>boolean</code> 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.
*
* @param c The <code>char</code> to be printed
*/
public void print(char c) {
write(String.valueOf(c));
}
/**
* Print an integer. The string printed is the same as that returned by
* the <code>toString</code> method of the <code>Integer</code> class when
* invoked on the given <code>int</code> value.
*
* @param i The <code>int</code> to be printed
* @see java.lang.Integer#toString(int)
*/
public void print(int i) {
write(String.valueOf(i));
}
/**
* Print a long integer. The string printed is the same as that returned
* by the <code>toString</code> method of the <code>Long</code> class when
* invoked on the given <code>long</code> value.
*
* @param l The <code>long</code> 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 printed is the same as that
* returned by the <code>toString</code> method of the <code>Float</code>
* class when invoked on the given <code>float</code> value.
*
* @param f The <code>float</code> 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 printed is
* the same as that returned by the <code>toString</code> method of the
* <code>Double</code> class when invoked on the given <code>double</code>
* value.
*
* @param d The <code>double</code> 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.
*
* @param s The array of chars to be printed
*/
public void print(char s[]) {
write(s);
}
/**
* Print a string. If the argument is <code>null</code>, the string
* <code>"null"</code> is written to the underlying output stream.
* Otherwise, the string's characters are converted into bytes according to
* the platform's default character encoding.
*
* @param s The <code>String</code> to be printed
*/
public void print(String s) {
if (s == null) {
s = "null";
}
write(s);
}
/**
* Print an object. The string printed is the same as that returned by the
* given object's <code>toString</code> method.
*
* @param obj The <code>Object</code> to be printed
* @see java.lang.Object#toString()
*/
public void print(Object obj) {
write(String.valueOf(obj));
}
/* Methods that do terminate lines */
/**
* Finish the current line by writing a line separator. The line
* separator string is defined by the system property
* <code>line.separator</code>, and is not necessarily a single newline
* character (<code>'\n'</code>).
*/
public void println() {
newLine();
}
/**
* Print a boolean, and then finish the line.
*
* @see #print(boolean)
*/
public void println(boolean x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print a character, and then finish the line.
*
* @see #print(char)
*/
public void println(char x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print an integer, and then finish the line.
*
* @see #print(int)
*/
public void println(int x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print a long, and then finish the line.
*
* @see #print(long)
*/
public void println(long x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print a float, and then finish the line.
*
* @see #print(float)
*/
public void println(float x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print a double, and then finish the line.
*
* @see #print(double)
*/
public void println(double x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print an array of characters, and then finish the line.
*
* @see #print(char[])
*/
public void println(char x[]) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print a String, and then finish the line.
*
* @see #print(String)
*/
public void println(String x) {
synchronized (this) {
print(x);
newLine();
}
}
/**
* Print an Object, and then finish the line.
*
* @see #print(Object)
*/
public void println(Object x) {
synchronized (this) {
print(x);
newLine();
}
}
}