File	Doc	Category	Size	Date	Package
PrintWriter.java	API Doc	Java SE 6 API	34643	Tue Jun 10 00:25:34 BST 2008	java.io

PrintWriter

• java.lang.Object
  • java.io.Writer

Fields Summary
protected Writer	out The underlying character-output stream of this PrintWriter.
private boolean	autoFlush
private boolean	trouble
private Formatter	formatter
private PrintStream	psOut
private String	lineSeparator Line separator string. This is the value of the line.separator property at the moment that the stream was created.

Constructors Summary
public PrintWriter(Writer out) Creates a new PrintWriter, without automatic line flushing. param out A character-output stream this(out, false);
public PrintWriter(Writer out, boolean autoFlush) Creates a new PrintWriter. param out A character-output stream param autoFlush A boolean; if true, the println, printf, or format methods will flush the output buffer super(out); this.out = out; this.autoFlush = autoFlush; lineSeparator = (String) java.security.AccessController.doPrivileged( new sun.security.action.GetPropertyAction("line.separator"));
public PrintWriter(OutputStream out) Creates a new PrintWriter, without automatic line flushing, from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding. param out An output stream see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream) this(out, false);
public PrintWriter(OutputStream out, boolean autoFlush) Creates a new PrintWriter from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding. param out An output stream param autoFlush A boolean; if true, the println, printf, or format methods will flush the output buffer see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream) this(new BufferedWriter(new OutputStreamWriter(out)), autoFlush); // save print stream for error propagation if (out instanceof java.io.PrintStream) { psOut = (PrintStream) out; }
public PrintWriter(String fileName) Creates a new PrintWriter, without automatic line flushing, with the specified file name. This convenience constructor creates the necessary intermediate {@link java.io.OutputStreamWriter OutputStreamWriter}, which will encode characters using the {@linkplain java.nio.charset.Charset#defaultCharset() default charset} for this instance of the Java virtual machine. param fileName The name of the file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered. throws FileNotFoundException If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file throws SecurityException If a security manager is present and {@link SecurityManager#checkWrite checkWrite(fileName)} denies write access to the file since 1.5 this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName))), false);
public PrintWriter(String fileName, String csn) Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset. This convenience constructor creates the necessary intermediate {@link java.io.OutputStreamWriter OutputStreamWriter}, which will encode characters using the provided charset. param fileName The name of the file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered. param csn The name of a supported {@linkplain java.nio.charset.Charset charset} throws FileNotFoundException If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file throws SecurityException If a security manager is present and {@link SecurityManager#checkWrite checkWrite(fileName)} denies write access to the file throws UnsupportedEncodingException If the named charset is not supported since 1.5 this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName), csn)), false);
public PrintWriter(File file) Creates a new PrintWriter, without automatic line flushing, with the specified file. This convenience constructor creates the necessary intermediate {@link java.io.OutputStreamWriter OutputStreamWriter}, which will encode characters using the {@linkplain java.nio.charset.Charset#defaultCharset() default charset} for this instance of the Java virtual machine. param file The file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered. throws FileNotFoundException If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file throws SecurityException If a security manager is present and {@link SecurityManager#checkWrite checkWrite(file.getPath())} denies write access to the file since 1.5 this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file))), false);
public PrintWriter(File file, String csn) Creates a new PrintWriter, without automatic line flushing, with the specified file and charset. This convenience constructor creates the necessary intermediate {@link java.io.OutputStreamWriter OutputStreamWriter}, which will encode characters using the provided charset. param file The file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered. param csn The name of a supported {@linkplain java.nio.charset.Charset charset} throws FileNotFoundException If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file throws SecurityException If a security manager is present and {@link SecurityManager#checkWrite checkWrite(file.getPath())} denies write access to the file throws UnsupportedEncodingException If the named charset is not supported since 1.5 this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), csn)), false);

Methods Summary
public java.io.PrintWriter	append(java.lang.CharSequence csq) Appends the specified character sequence to this writer. An invocation of this method of the form out.append(csq) behaves in exactly the same way as the invocation out.write(csq.toString()) Depending on the specification of toString for the character sequence csq, the entire sequence may not be appended. For instance, invoking the toString method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit. param csq The character sequence to append. If csq is null, then the four characters "null" are appended to this writer. return This writer since 1.5 if (csq == null) write("null"); else write(csq.toString()); return this;
public java.io.PrintWriter	append(java.lang.CharSequence csq, int start, int end) Appends a subsequence of the specified character sequence to this writer. An invocation of this method of the form out.append(csq, start, end) when csq is not null, behaves in exactly the same way as the invocation out.write(csq.subSequence(start, end).toString()) param csq The character sequence from which a subsequence will be appended. If csq is null, then characters will be appended as if csq contained the four characters "null". param start The index of the first character in the subsequence param end The index of the character following the last character in the subsequence return This writer throws IndexOutOfBoundsException If start or end are negative, start is greater than end, or end is greater than csq.length() since 1.5 CharSequence cs = (csq == null ? "null" : csq); write(cs.subSequence(start, end).toString()); return this;
public java.io.PrintWriter	append(char c) Appends the specified character to this writer. An invocation of this method of the form out.append(c) behaves in exactly the same way as the invocation out.write(c) param c The 16-bit character to append return This writer since 1.5 write(c); return this;
public boolean	checkError() Flushes the stream if it's not closed and checks its error state. return true if the print stream has encountered an error, either on the underlying output stream or during a format conversion. if (out != null) { flush(); } if (out instanceof java.io.PrintWriter) { PrintWriter pw = (PrintWriter) out; return pw.checkError(); } else if (psOut != null) { return psOut.checkError(); } return trouble;
protected void	clearError() Clears the error state of this stream. This method will cause subsequent invocations of {@link #checkError()} to return false until another write operation fails and invokes {@link #setError()}. since 1.6 trouble = false;
public void	close() Closes the stream and releases any system resources associated with it. Closing a previously closed stream has no effect. see #checkError() try { synchronized (lock) { if (out == null) return; out.close(); out = null; } } catch (IOException x) { trouble = true; }
private void	ensureOpen() Checks to make sure that the stream has not been closed if (out == null) throw new IOException("Stream closed");
public void	flush() Flushes the stream. see #checkError() try { synchronized (lock) { ensureOpen(); out.flush(); } } catch (IOException x) { trouble = true; }
public java.io.PrintWriter	format(java.lang.String format, java.lang.Object args) Writes a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer. The locale always used is the one returned by {@link java.util.Locale#getDefault() Locale.getDefault()}, regardless of any previous invocations of other formatting methods on this object. param format A format string as described in Format string syntax. param args Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion. throws IllegalFormatException If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the Formatter class specification. throws NullPointerException If the format is null return This writer since 1.5 try { synchronized (lock) { ensureOpen(); if ((formatter == null) || (formatter.locale() != Locale.getDefault())) formatter = new Formatter(this); formatter.format(Locale.getDefault(), format, args); if (autoFlush) out.flush(); } } catch (InterruptedIOException x) { Thread.currentThread().interrupt(); } catch (IOException x) { trouble = true; } return this;
public java.io.PrintWriter	format(java.util.Locale l, java.lang.String format, java.lang.Object args) Writes a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer. param l The {@linkplain java.util.Locale locale} to apply during formatting. If l is null then no localization is applied. param format A format string as described in Format string syntax. param args Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion. throws IllegalFormatException If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification. throws NullPointerException If the format is null return This writer since 1.5 try { synchronized (lock) { ensureOpen(); if ((formatter == null) || (formatter.locale() != l)) formatter = new Formatter(this, l); formatter.format(l, format, args); if (autoFlush) out.flush(); } } catch (InterruptedIOException x) { Thread.currentThread().interrupt(); } catch (IOException x) { trouble = true; } return this;
private void	newLine() try { synchronized (lock) { ensureOpen(); out.write(lineSeparator); if (autoFlush) out.flush(); } } catch (InterruptedIOException x) { Thread.currentThread().interrupt(); } catch (IOException x) { trouble = true; }
public void	print(boolean b) Prints 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 write(b ? "true" : "false");
public void	print(char c) Prints 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 write(c);
public void	print(int i) Prints 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) write(String.valueOf(i));
public void	print(long l) Prints 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) write(String.valueOf(l));
public void	print(float f) Prints 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) write(String.valueOf(f));
public void	print(double d) Prints 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) write(String.valueOf(d));
public void	print(char[] s) Prints 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 write(s);
public void	print(java.lang.String s) Prints 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 if (s == null) { s = "null"; } write(s);
public void	print(java.lang.Object obj) Prints 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() write(String.valueOf(obj));
public java.io.PrintWriter	printf(java.lang.String format, java.lang.Object args) A convenience method to write a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer. An invocation of this method of the form out.printf(format, args) behaves in exactly the same way as the invocation out.format(format, args) param format A format string as described in Format string syntax. param args Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion. throws IllegalFormatException If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification. throws NullPointerException If the format is null return This writer since 1.5 return format(format, args);
public java.io.PrintWriter	printf(java.util.Locale l, java.lang.String format, java.lang.Object args) A convenience method to write a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer. An invocation of this method of the form out.printf(l, format, args) behaves in exactly the same way as the invocation out.format(l, format, args) param l The {@linkplain java.util.Locale locale} to apply during formatting. If l is null then no localization is applied. param format A format string as described in Format string syntax. param args Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion. throws IllegalFormatException If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification. throws NullPointerException If the format is null return This writer since 1.5 return format(l, format, args);
public void	println() Terminates 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'). newLine();
public void	println(boolean x) Prints a boolean value and then terminates the line. This method behaves as though it invokes {@link #print(boolean)} and then {@link #println()}. param x the boolean value to be printed synchronized (lock) { print(x); println(); }
public void	println(char x) Prints a character and then terminates the line. This method behaves as though it invokes {@link #print(char)} and then {@link #println()}. param x the char value to be printed synchronized (lock) { print(x); println(); }
public void	println(int x) Prints an integer and then terminates the line. This method behaves as though it invokes {@link #print(int)} and then {@link #println()}. param x the int value to be printed synchronized (lock) { print(x); println(); }
public void	println(long x) Prints a long integer and then terminates the line. This method behaves as though it invokes {@link #print(long)} and then {@link #println()}. param x the long value to be printed synchronized (lock) { print(x); println(); }
public void	println(float x) Prints a floating-point number and then terminates the line. This method behaves as though it invokes {@link #print(float)} and then {@link #println()}. param x the float value to be printed synchronized (lock) { print(x); println(); }
public void	println(double x) Prints a double-precision floating-point number and then terminates the line. This method behaves as though it invokes {@link #print(double)} and then {@link #println()}. param x the double value to be printed synchronized (lock) { print(x); println(); }
public void	println(char[] x) Prints an array of characters and then terminates the line. This method behaves as though it invokes {@link #print(char[])} and then {@link #println()}. param x the array of char values to be printed synchronized (lock) { print(x); println(); }
public void	println(java.lang.String x) Prints a String and then terminates the line. This method behaves as though it invokes {@link #print(String)} and then {@link #println()}. param x the String value to be printed synchronized (lock) { print(x); println(); }
public void	println(java.lang.Object x) Prints an Object and then terminates the line. This method calls at first String.valueOf(x) to get the printed object's string value, then behaves as though it invokes {@link #print(String)} and then {@link #println()}. param x The Object to be printed. String s = String.valueOf(x); synchronized (lock) { print(s); println(); }
protected void	setError() Indicates that an error has occurred. This method will cause subsequent invocations of {@link #checkError()} to return true until {@link #clearError()} is invoked. trouble = true;
public void	write(int c) Writes a single character. param c int specifying a character to be written. try { synchronized (lock) { ensureOpen(); out.write(c); } } catch (InterruptedIOException x) { Thread.currentThread().interrupt(); } catch (IOException x) { trouble = true; }
public void	write(char[] buf, int off, int len) Writes A Portion of an array of characters. param buf Array of characters param off Offset from which to start writing characters param len Number of characters to write try { synchronized (lock) { ensureOpen(); out.write(buf, off, len); } } catch (InterruptedIOException x) { Thread.currentThread().interrupt(); } catch (IOException x) { trouble = true; }
public void	write(char[] buf) Writes an array of characters. This method cannot be inherited from the Writer class because it must suppress I/O exceptions. param buf Array of characters to be written write(buf, 0, buf.length);
public void	write(java.lang.String s, int off, int len) Writes a portion of a string. param s A String param off Offset from which to start writing characters param len Number of characters to write try { synchronized (lock) { ensureOpen(); out.write(s, off, len); } } catch (InterruptedIOException x) { Thread.currentThread().interrupt(); } catch (IOException x) { trouble = true; }
public void	write(java.lang.String s) Writes a string. This method cannot be inherited from the Writer class because it must suppress I/O exceptions. param s String to be written write(s, 0, s.length());