/*
 * Copyright (c) 1996, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation. Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.io;

import java.util.Objects;
import java.util.Formatter;
import java.util.Locale;
import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;

/**
 * Prints formatted representations of objects to a text-output stream. This
 * class implements all of the {@code print} methods found in {@link
 * PrintStream}. It does not contain methods for writing raw bytes, for which
 * a program should use unencoded byte streams.
 *
 * <p> Unlike the {@link PrintStream} class, if automatic flushing is enabled
 * it will be done only when one of the {@code println}, {@code printf}, or
 * {@code format} methods is invoked, rather than whenever a newline character
 * happens to be output. These methods use the platform's own notion of line
 * separator rather than the newline character.
 *
 * <p> Methods in this class never throw I/O exceptions, although some of its
 * constructors may. The client may inquire as to whether any errors have
 * occurred by invoking {@link #checkError checkError()}.
 *
 * <p> This class always replaces malformed and unmappable character sequences with
 * the charset's default replacement string.
 * The {@linkplain java.nio.charset.CharsetEncoder} class should be used when more
 * control over the encoding process is required.
 *
 * @author Frank Yellin
 * @author Mark Reinhold
 * @since 1.1
 */

public class PrintWriter extends Writer {

 /**
 * The underlying character-output stream of this
 * {@code PrintWriter}.
 *
 * @since 1.2
 */
 protected Writer out;

 private final boolean autoFlush;
 private boolean trouble = false;
 private Formatter formatter;
 private PrintStream psOut = null;

 /**
 * Returns a charset object for the given charset name.
 * @throws NullPointerException is csn is null
 * @throws UnsupportedEncodingException if the charset is not supported
 */
 private static Charset toCharset(String csn)
 throws UnsupportedEncodingException
 {
 Objects.requireNonNull(csn, "charsetName");
 try {
 return Charset.forName(csn);
 } catch (IllegalCharsetNameException|UnsupportedCharsetException unused) {
 // UnsupportedEncodingException should be thrown
 throw new UnsupportedEncodingException(csn);
 }
 }

 /**
 * Creates a new PrintWriter, without automatic line flushing.
 *
 * @param out A character-output stream
 */
 public PrintWriter (Writer out) {
 this(out, false);
 }

 /**
 * Creates a new PrintWriter.
 *
 * @param out A character-output stream
 * @param autoFlush A boolean; if true, the {@code println},
 * {@code printf}, or {@code format} methods will
 * flush the output buffer
 */
 public PrintWriter(Writer out,
 boolean autoFlush) {
 super(out);
 this.out = out;
 this.autoFlush = autoFlush;
 }

 /**
 * 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)
 */
 public PrintWriter(OutputStream out) {
 this(out, false);
 }

 /**
 * 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 {@code println},
 * {@code printf}, or {@code format} methods will
 * flush the output buffer
 *
 * @see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream)
 */
 public PrintWriter(OutputStream out, boolean autoFlush) {
 this(out, autoFlush, Charset.defaultCharset());
 }

 /**
 * Creates a new PrintWriter from an existing OutputStream. This
 * convenience constructor creates the necessary intermediate
 * OutputStreamWriter, which will convert characters into bytes using the
 * specified charset.
 *
 * @param out An output stream
 * @param autoFlush A boolean; if true, the {@code println},
 * {@code printf}, or {@code format} methods will
 * flush the output buffer
 * @param charset
 * A {@linkplain java.nio.charset.Charset charset}
 *
 * @since 10
 */
 public PrintWriter(OutputStream out, boolean autoFlush, Charset charset) {
 this(new BufferedWriter(new OutputStreamWriter(out, charset)), autoFlush);

 // save print stream for error propagation
 if (out instanceof java.io.PrintStream) {
 psOut = (PrintStream) out;
 }
 }

 /**
 * 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
 */
 public PrintWriter(String fileName) throws FileNotFoundException {
 this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName))),
 false);
 }

 /* Private constructor */
 private PrintWriter(Charset charset, File file)
 throws FileNotFoundException
 {
 this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), charset)),
 false);
 }

 /**
 * 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
 */
 public PrintWriter(String fileName, String csn)
 throws FileNotFoundException, UnsupportedEncodingException
 {
 this(toCharset(csn), new File(fileName));
 }

 /**
 * 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 charset
 * A {@linkplain java.nio.charset.Charset charset}
 *
 * @throws IOException
 * if an I/O 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 10
 */
 public PrintWriter(String fileName, Charset charset) throws IOException {
 this(Objects.requireNonNull(charset, "charset"), new File(fileName));
 }

 /**
 * 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
 */
 public PrintWriter(File file) throws FileNotFoundException {
 this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file))),
 false);
 }

 /**
 * 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
 */
 public PrintWriter(File file, String csn)
 throws FileNotFoundException, UnsupportedEncodingException
 {
 this(toCharset(csn), file);
 }

 /**
 * 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 charset
 * A {@linkplain java.nio.charset.Charset charset}
 *
 * @throws IOException
 * if an I/O 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 10
 */
 public PrintWriter(File file, Charset charset) throws IOException {
 this(Objects.requireNonNull(charset, "charset"), file);
 }

 /** Checks to make sure that the stream has not been closed */
 private void ensureOpen() throws IOException {
 if (out == null)
 throw new IOException("Stream closed");
 }

 /**
 * Flushes the stream.
 * @see #checkError()
 */
 public void flush() {
 try {
 synchronized (lock) {
 ensureOpen();
 out.flush();
 }
 }
 catch (IOException x) {
 trouble = true;
 }
 }

 /**
 * Closes the stream and releases any system resources associated
 * with it. Closing a previously closed stream has no effect.
 *
 * @see #checkError()
 */
 public void close() {
 try {
 synchronized (lock) {
 if (out == null)
 return;
 out.close();
 out = null;
 }
 }
 catch (IOException x) {
 trouble = true;
 }
 }

 /**
 * Flushes the stream if it's not closed and checks its error state.
 *
 * @return {@code true} if the print stream has encountered an error,
 * either on the underlying output stream or during a format
 * conversion.
 */
 public boolean checkError() {
 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;
 }

 /**
 * Indicates that an error has occurred.
 *
 * <p> This method will cause subsequent invocations of {@link
 * #checkError()} to return {@code true} until {@link
 * #clearError()} is invoked.
 */
 protected void setError() {
 trouble = true;
 }

 /**
 * Clears the error state of this stream.
 *
 * <p> This method will cause subsequent invocations of {@link
 * #checkError()} to return {@code false} until another write
 * operation fails and invokes {@link #setError()}.
 *
 * @since 1.6
 */
 protected void clearError() {
 trouble = false;
 }

 /*
 * Exception-catching, synchronized output operations,
 * which also implement the write() methods of Writer
 */

 /**
 * Writes a single character.
 * @param c int specifying a character to be written.
 */
 public void write(int c) {
 try {
 synchronized (lock) {
 ensureOpen();
 out.write(c);
 }
 }
 catch (InterruptedIOException x) {
 Thread.currentThread().interrupt();
 }
 catch (IOException x) {
 trouble = true;
 }
 }

 /**
 * 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
 *
 * @throws IndexOutOfBoundsException
 * If the values of the {@code off} and {@code len} parameters
 * cause the corresponding method of the underlying {@code Writer}
 * to throw an {@code IndexOutOfBoundsException}
 */
 public void write(char buf[], int off, int len) {
 try {
 synchronized (lock) {
 ensureOpen();
 out.write(buf, off, len);
 }
 }
 catch (InterruptedIOException x) {
 Thread.currentThread().interrupt();
 }
 catch (IOException x) {
 trouble = true;
 }
 }

 /**
 * 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
 */
 public void write(char buf[]) {
 write(buf, 0, buf.length);
 }

 /**
 * 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
 *
 * @throws IndexOutOfBoundsException
 * If the values of the {@code off} and {@code len} parameters
 * cause the corresponding method of the underlying {@code Writer}
 * to throw an {@code IndexOutOfBoundsException}
 */
 public void write(String s, int off, int len) {
 try {
 synchronized (lock) {
 ensureOpen();
 out.write(s, off, len);
 }
 }
 catch (InterruptedIOException x) {
 Thread.currentThread().interrupt();
 }
 catch (IOException x) {
 trouble = true;
 }
 }

 /**
 * 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
 */
 public void write(String s) {
 write(s, 0, s.length());
 }

 private void newLine() {
 try {
 synchronized (lock) {
 ensureOpen();
 out.write(System.lineSeparator());
 if (autoFlush)
 out.flush();
 }
 }
 catch (InterruptedIOException x) {
 Thread.currentThread().interrupt();
 }
 catch (IOException x) {
 trouble = true;
 }
 }

 /* Methods that do not terminate lines */

 /**
 * 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 {@code boolean} to be printed
 */
 public void print(boolean b) {
 write(String.valueOf(b));
 }

 /**
 * 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 {@code char} to be printed
 */
 public void print(char c) {
 write(c);
 }

 /**
 * 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 {@code int} to be printed
 * @see java.lang.Integer#toString(int)
 */
 public void print(int i) {
 write(String.valueOf(i));
 }

 /**
 * 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 {@code long} to be printed
 * @see java.lang.Long#toString(long)
 */
 public void print(long l) {
 write(String.valueOf(l));
 }

 /**
 * 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 {@code float} to be printed
 * @see java.lang.Float#toString(float)
 */
 public void print(float f) {
 write(String.valueOf(f));
 }

 /**
 * 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 {@code double} to be printed
 * @see java.lang.Double#toString(double)
 */
 public void print(double d) {
 write(String.valueOf(d));
 }

 /**
 * 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 {@code s} is {@code null}
 */
 public void print(char s[]) {
 write(s);
 }

 /**
 * Prints a string. If the argument is {@code null} then the string
 * {@code "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 {@code String} to be printed
 */
 public void print(String s) {
 write(String.valueOf(s));
 }

 /**
 * 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 {@code Object} to be printed
 * @see java.lang.Object#toString()
 */
 public void print(Object obj) {
 write(String.valueOf(obj));
 }

 /* Methods that do terminate lines */

 /**
 * Terminates the current line by writing the line separator string. The
 * line separator string is defined by the system property
 * {@code line.separator}, and is not necessarily a single newline
 * character ({@code '\n'}).
 */
 public void println() {
 newLine();
 }

 /**
 * 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 {@code boolean} value to be printed
 */
 public void println(boolean x) {
 synchronized (lock) {
 print(x);
 println();
 }
 }

 /**
 * 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 {@code char} value to be printed
 */
 public void println(char x) {
 synchronized (lock) {
 print(x);
 println();
 }
 }

 /**
 * 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 {@code int} value to be printed
 */
 public void println(int x) {
 synchronized (lock) {
 print(x);
 println();
 }
 }

 /**
 * 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 {@code long} value to be printed
 */
 public void println(long x) {
 synchronized (lock) {
 print(x);
 println();
 }
 }

 /**
 * 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 {@code float} value to be printed
 */
 public void println(float x) {
 synchronized (lock) {
 print(x);
 println();
 }
 }

 /**
 * 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 {@code double} value to be printed
 */
 public void println(double x) {
 synchronized (lock) {
 print(x);
 println();
 }
 }

 /**
 * 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 {@code char} values to be printed
 */
 public void println(char x[]) {
 synchronized (lock) {
 print(x);
 println();
 }
 }

 /**
 * 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 {@code String} value to be printed
 */
 public void println(String x) {
 synchronized (lock) {
 print(x);
 println();
 }
 }

 /**
 * 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 {@code Object} to be printed.
 */
 public void println(Object x) {
 String s = String.valueOf(x);
 synchronized (lock) {
 print(s);
 println();
 }
 }

 /**
 * 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.
 *
 * <p> An invocation of this method of the form
 * {@code out.printf(format, args)}
 * behaves in exactly the same way as the invocation
 *
 * <pre>{@code
 * out.format(format, args)
 * }</pre>
 *
 * @param format
 * A format string as described in <a
 * href="../util/Formatter.html#syntax">Format string syntax</a>.
 *
 * @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
 * <cite>The Java&trade; Virtual Machine Specification</cite>.
 * The behaviour on a
 * {@code null} argument depends on the <a
 * href="../util/Formatter.html#syntax">conversion</a>.
 *
 * @throws java.util.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 <a
 * href="../util/Formatter.html#detail">Details</a> section of the
 * formatter class specification.
 *
 * @throws NullPointerException
 * If the {@code format} is {@code null}
 *
 * @return This writer
 *
 * @since 1.5
 */
 public PrintWriter printf(String format, Object ... args) {
 return format(format, 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.
 *
 * <p> An invocation of this method of the form
 * {@code out.printf(l, format, args)}
 * behaves in exactly the same way as the invocation
 *
 * <pre>{@code
 * out.format(l, format, args)
 * }</pre>
 *
 * @param l
 * The {@linkplain java.util.Locale locale} to apply during
 * formatting. If {@code l} is {@code null} then no localization
 * is applied.
 *
 * @param format
 * A format string as described in <a
 * href="../util/Formatter.html#syntax">Format string syntax</a>.
 *
 * @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
 * <cite>The Java&trade; Virtual Machine Specification</cite>.
 * The behaviour on a
 * {@code null} argument depends on the <a
 * href="../util/Formatter.html#syntax">conversion</a>.
 *
 * @throws java.util.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 <a
 * href="../util/Formatter.html#detail">Details</a> section of the
 * formatter class specification.
 *
 * @throws NullPointerException
 * If the {@code format} is {@code null}
 *
 * @return This writer
 *
 * @since 1.5
 */
 public PrintWriter printf(Locale l, String format, Object ... args) {
 return format(l, format, 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.
 *
 * <p> 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 <a
 * href="../util/Formatter.html#syntax">Format string syntax</a>.
 *
 * @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
 * <cite>The Java&trade; Virtual Machine Specification</cite>.
 * The behaviour on a
 * {@code null} argument depends on the <a
 * href="../util/Formatter.html#syntax">conversion</a>.
 *
 * @throws java.util.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 <a
 * href="../util/Formatter.html#detail">Details</a> section of the
 * Formatter class specification.
 *
 * @throws NullPointerException
 * If the {@code format} is {@code null}
 *
 * @return This writer
 *
 * @since 1.5
 */
 public PrintWriter format(String format, Object ... args) {
 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;
 }

 /**
 * 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 {@code l} is {@code null} then no localization
 * is applied.
 *
 * @param format
 * A format string as described in <a
 * href="../util/Formatter.html#syntax">Format string syntax</a>.
 *
 * @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
 * <cite>The Java&trade; Virtual Machine Specification</cite>.
 * The behaviour on a
 * {@code null} argument depends on the <a
 * href="../util/Formatter.html#syntax">conversion</a>.
 *
 * @throws java.util.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 <a
 * href="../util/Formatter.html#detail">Details</a> section of the
 * formatter class specification.
 *
 * @throws NullPointerException
 * If the {@code format} is {@code null}
 *
 * @return This writer
 *
 * @since 1.5
 */
 public PrintWriter format(Locale l, String format, Object ... args) {
 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;
 }

 /**
 * Appends the specified character sequence to this writer.
 *
 * <p> An invocation of this method of the form {@code out.append(csq)}
 * behaves in exactly the same way as the invocation
 *
 * <pre>{@code
 * out.write(csq.toString())
 * }</pre>
 *
 * <p> Depending on the specification of {@code toString} for the
 * character sequence {@code csq}, the entire sequence may not be
 * appended. For instance, invoking the {@code 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 {@code csq} is
 * {@code null}, then the four characters {@code "null"} are
 * appended to this writer.
 *
 * @return This writer
 *
 * @since 1.5
 */
 public PrintWriter append(CharSequence csq) {
 write(String.valueOf(csq));
 return this;
 }

 /**
 * Appends a subsequence of the specified character sequence to this writer.
 *
 * <p> An invocation of this method of the form
 * {@code out.append(csq, start, end)}
 * when {@code csq} is not {@code null}, behaves in
 * exactly the same way as the invocation
 *
 * <pre>{@code
 * out.write(csq.subSequence(start, end).toString())
 * }</pre>
 *
 * @param csq
 * The character sequence from which a subsequence will be
 * appended. If {@code csq} is {@code null}, then characters
 * will be appended as if {@code csq} contained the four
 * characters {@code "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 {@code start} or {@code end} are negative, {@code start}
 * is greater than {@code end}, or {@code end} is greater than
 * {@code csq.length()}
 *
 * @since 1.5
 */
 public PrintWriter append(CharSequence csq, int start, int end) {
 if (csq == null) csq = "null";
 return append(csq.subSequence(start, end));
 }

 /**
 * Appends the specified character to this writer.
 *
 * <p> An invocation of this method of the form {@code out.append(c)}
 * behaves in exactly the same way as the invocation
 *
 * <pre>{@code
 * out.write(c)
 * }</pre>
 *
 * @param c
 * The 16-bit character to append
 *
 * @return This writer
 *
 * @since 1.5
 */
 public PrintWriter append(char c) {
 write(c);
 return this;
 }
}