/*

 * Copyright (c) 1996, 2011, 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 <tt>print</tt> 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 <tt>println</tt>, <tt>printf</tt>, or

 * <tt>format</tt> 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()}.

 *

 * @author      Frank Yellin

 * @author      Mark Reinhold

 * @since       JDK1.1

 */

public class PrintWriter extends Writer {

    /**

     * The underlying character-output stream of this

     * <code>PrintWriter</code>.

     *

     * @since 1.2

     */

    protected Writer out;

    private final boolean autoFlush;

    private boolean trouble = false;

    private Formatter formatter;

    private PrintStream psOut = null;

    /**

     * Line separator string.  This is the value of the line.separator

     * property at the moment that the stream was created.

     */

    private final String lineSeparator;

    /**

     * 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 <tt>println</tt>,

     *                    <tt>printf</tt>, or <tt>format</tt> methods will

     *                    flush the output buffer

     */

    public PrintWriter(Writer out,

                       boolean autoFlush) {

        super(out);

        this.out = out;

        this.autoFlush = autoFlush;

        lineSeparator = java.security.AccessController.doPrivileged(

            new sun.security.action.GetPropertyAction("line.separator"));

    }

    /**

     * 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 <tt>println</tt>,

     *                    <tt>printf</tt>, or <tt>format</tt> methods will

     *                    flush the output buffer

     *

     * @see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream)

     */

    public PrintWriter(OutputStream out, boolean autoFlush) {

        this(new BufferedWriter(new OutputStreamWriter(out)), 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.  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);

    }

    /** 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</code> 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 <tt>true</tt> 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 <tt>false</tt> 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

     */

    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

     */

    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(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 <code>{@link

     * java.lang.String#valueOf(boolean)}</code> is translated into bytes

     * according to the platform's default character encoding, and these bytes

     * are written in exactly the manner of the <code>{@link

     * #write(int)}</code> method.

     *

     * @param      b   The <code>boolean</code> to be printed

     */

    public void print(boolean b) {

        write(b ? "true" : "false");

    }

    /**

     * 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 <code>{@link

     * #write(int)}</code> method.

     *

     * @param      c   The <code>char</code> to be printed

     */

    public void print(char c) {

        write(c);

    }

    /**

     * Prints an integer.  The string produced by <code>{@link

     * java.lang.String#valueOf(int)}</code> is translated into bytes according

     * to the platform's default character encoding, and these bytes are

     * written in exactly the manner of the <code>{@link #write(int)}</code>

     * method.

     *

     * @param      i   The <code>int</code> 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 <code>{@link

     * java.lang.String#valueOf(long)}</code> is translated into bytes

     * according to the platform's default character encoding, and these bytes

     * are written in exactly the manner of the <code>{@link #write(int)}</code>

     * method.

     *

     * @param      l   The <code>long</code> 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 <code>{@link

     * java.lang.String#valueOf(float)}</code> is translated into bytes

     * according to the platform's default character encoding, and these bytes

     * are written in exactly the manner of the <code>{@link #write(int)}</code>

     * method.

     *

     * @param      f   The <code>float</code> 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

     * <code>{@link java.lang.String#valueOf(double)}</code> is translated into

     * bytes according to the platform's default character encoding, and these

     * bytes are written in exactly the manner of the <code>{@link

     * #write(int)}</code> method.

     *

     * @param      d   The <code>double</code> 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 <code>{@link #write(int)}</code>

     * method.

     *

     * @param      s   The array of chars to be printed

     *

     * @throws  NullPointerException  If <code>s</code> is <code>null</code>

     */

    public void print(char s[]) {

        write(s);

    }

    /**

     * Prints a string.  If the argument is <code>null</code> then the string

     * <code>"null"</code> 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

     * <code>{@link #write(int)}</code> method.

     *

     * @param      s   The <code>String</code> to be printed

     */

    public void print(String s) {

        if (s == null) {

            s = "null";

        }

        write(s);

    }

    /**

     * Prints an object.  The string produced by the <code>{@link

     * java.lang.String#valueOf(Object)}</code> method is translated into bytes

     * according to the platform's default character encoding, and these bytes

     * are written in exactly the manner of the <code>{@link #write(int)}</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 */

    /**

     * Terminates the current line by writing the line separator string.  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();

    }

    /**

     * Prints a boolean value and then terminates the line.  This method behaves

     * as though it invokes <code>{@link #print(boolean)}</code> and then

     * <code>{@link #println()}</code>.

     *

     * @param x the <code>boolean</code> 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 <code>{@link #print(char)}</code> and then <code>{@link

     * #println()}</code>.

     *

     * @param x the <code>char</code> 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 <code>{@link #print(int)}</code> and then <code>{@link

     * #println()}</code>.

     *

     * @param x the <code>int</code> 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 <code>{@link #print(long)}</code> and then

     * <code>{@link #println()}</code>.

     *

     * @param x the <code>long</code> 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 <code>{@link #print(float)}</code> and then

     * <code>{@link #println()}</code>.

     *

     * @param x the <code>float</code> 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 <code>{@link

     * #print(double)}</code> and then <code>{@link #println()}</code>.

     *

     * @param x the <code>double</code> 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 <code>{@link #print(char[])}</code> and then

     * <code>{@link #println()}</code>.

     *

     * @param x the array of <code>char</code> 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 <code>{@link #print(String)}</code> and then

     * <code>{@link #println()}</code>.

     *

     * @param x the <code>String</code> 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 <code>{@link #print(String)}</code> and then

     * <code>{@link #println()}</code>.

     *

     * @param x  The <code>Object</code> 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 <tt>out.printf(format,

     * args)</tt> behaves in exactly the same way as the invocation

     *

     * <pre>

     *     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

     *         <tt>null</tt> argument depends on the <a

     *         href="../util/Formatter.html#syntax">conversion</a>.

     *

     * @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 <a

     *          href="../util/Formatter.html#detail">Details</a> section of the

     *          formatter class specification.

     *

     * @throws  NullPointerException

     *          If the <tt>format</tt> is <tt>null</tt>

     *

     * @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 <tt>out.printf(l, format,

     * args)</tt> behaves in exactly the same way as the invocation

     *

     * <pre>

     *     out.format(l, format, args) </pre>

     *

     * @param  l

     *         The {@linkplain java.util.Locale locale} to apply during

     *         formatting.  If <tt>l</tt> is <tt>null</tt> 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

     *         <tt>null</tt> argument depends on the <a

     *         href="../util/Formatter.html#syntax">conversion</a>.

     *

     * @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 <a

     *          href="../util/Formatter.html#detail">Details</a> section of the

     *          formatter class specification.

     *

     * @throws  NullPointerException

     *          If the <tt>format</tt> is <tt>null</tt>

     *

     * @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

     *         <tt>null</tt> argument depends on the <a

     *         href="../util/Formatter.html#syntax">conversion</a>.

     *

     * @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 <a

     *          href="../util/Formatter.html#detail">Details</a> section of the

     *          Formatter class specification.

     *

     * @throws  NullPointerException

     *          If the <tt>format</tt> is <tt>null</tt>

     *

     * @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 <tt>l</tt> is <tt>null</tt> 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

     *         <tt>null</tt> argument depends on the <a

     *         href="../util/Formatter.html#syntax">conversion</a>.

     *

     * @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 <a

     *          href="../util/Formatter.html#detail">Details</a> section of the

     *          formatter class specification.

     *

     * @throws  NullPointerException

     *          If the <tt>format</tt> is <tt>null</tt>

     *

     * @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 <tt>out.append(csq)</tt>

     * behaves in exactly the same way as the invocation

     *

     * <pre>

     *     out.write(csq.toString()) </pre>

     *

     * <p> Depending on the specification of <tt>toString</tt> for the

     * character sequence <tt>csq</tt>, the entire sequence may not be

     * appended. For instance, invoking the <tt>toString</tt> 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 <tt>csq</tt> is

     *         <tt>null</tt>, then the four characters <tt>"null"</tt> are

     *         appended to this writer.