/*

 * 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.Formatter;

import java.util.Locale;

import java.nio.charset.Charset;

import java.nio.charset.IllegalCharsetNameException;

import java.nio.charset.UnsupportedCharsetException;

/**

 * A <code>PrintStream</code> adds functionality to another output stream,

 * namely the ability to print representations of various data values

 * conveniently.  Two other features are provided as well.  Unlike other output

 * streams, a <code>PrintStream</code> never throws an

 * <code>IOException</code>; instead, exceptional situations merely set an

 * internal flag that can be tested via the <code>checkError</code> method.

 * Optionally, a <code>PrintStream</code> can be created so as to flush

 * automatically; this means that the <code>flush</code> method is

 * automatically invoked after a byte array is written, one of the

 * <code>println</code> methods is invoked, or a newline character or byte

 * (<code>'\n'</code>) is written.

 *

 * <p> All characters printed by a <code>PrintStream</code> are converted into

 * bytes using the platform's default character encoding.  The <code>{@link

 * PrintWriter}</code> class should be used in situations that require writing

 * characters rather than bytes.

 *

 * @author     Frank Yellin

 * @author     Mark Reinhold

 * @since      JDK1.0

 */

public class PrintStream extends FilterOutputStream

    implements Appendable, Closeable

{

    private final boolean autoFlush;

    private boolean trouble = false;

    private Formatter formatter;

    /**

     * Track both the text- and character-output streams, so that their buffers

     * can be flushed without flushing the entire stream.

     */

    private BufferedWriter textOut;

    private OutputStreamWriter charOut;

    /**

     * requireNonNull is explicitly declared here so as not to create an extra

     * dependency on java.util.Objects.requireNonNull. PrintStream is loaded

     * early during system initialization.

     */

    private static <T> T requireNonNull(T obj, String message) {

        if (obj == null)

            throw new NullPointerException(message);

        return obj;

    }

    /**

     * 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

    {

        requireNonNull(csn, "charsetName");

        try {

            return Charset.forName(csn);

        } catch (IllegalCharsetNameException|UnsupportedCharsetException unused) {

            // UnsupportedEncodingException should be thrown

            throw new UnsupportedEncodingException(csn);

        }

    }

    /* Private constructors */

    private PrintStream(boolean autoFlush, OutputStream out) {

        super(out);

        this.autoFlush = autoFlush;

        this.charOut = new OutputStreamWriter(this);

        this.textOut = new BufferedWriter(charOut);

    }

    private PrintStream(boolean autoFlush, OutputStream out, Charset charset) {

        super(out);

        this.autoFlush = autoFlush;

        this.charOut = new OutputStreamWriter(this, charset);

        this.textOut = new BufferedWriter(charOut);

    }

    /* Variant of the private constructor so that the given charset name

     * can be verified before evaluating the OutputStream argument. Used

     * by constructors creating a FileOutputStream that also take a

     * charset name.

     */

    private PrintStream(boolean autoFlush, Charset charset, OutputStream out)

        throws UnsupportedEncodingException

    {

        this(autoFlush, out, charset);

    }

    /**

     * Creates a new print stream.  This stream will not flush automatically.

     *

     * @param  out        The output stream to which values and objects will be

     *                    printed

     *

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

     */

    public PrintStream(OutputStream out) {

        this(out, false);

    }

    /**

     * Creates a new print stream.

     *

     * @param  out        The output stream to which values and objects will be

     *                    printed

     * @param  autoFlush  A boolean; if true, the output buffer will be flushed

     *                    whenever a byte array is written, one of the

     *                    <code>println</code> methods is invoked, or a newline

     *                    character or byte (<code>'\n'</code>) is written

     *

     * @see java.io.PrintWriter#PrintWriter(java.io.OutputStream, boolean)

     */

    public PrintStream(OutputStream out, boolean autoFlush) {

        this(autoFlush, requireNonNull(out, "Null output stream"));

    }

    /**

     * Creates a new print stream.

     *

     * @param  out        The output stream to which values and objects will be

     *                    printed

     * @param  autoFlush  A boolean; if true, the output buffer will be flushed

     *                    whenever a byte array is written, one of the

     *                    <code>println</code> methods is invoked, or a newline

     *                    character or byte (<code>'\n'</code>) is written

     * @param  encoding   The name of a supported

     *                    <a href="../lang/package-summary.html#charenc">

     *                    character encoding</a>

     *

     * @throws  UnsupportedEncodingException

     *          If the named encoding is not supported

     *

     * @since  1.4

     */

    public PrintStream(OutputStream out, boolean autoFlush, String encoding)

        throws UnsupportedEncodingException

    {

        this(autoFlush,

             requireNonNull(out, "Null output stream"),

             toCharset(encoding));

    }

    /**

     * Creates a new print stream, 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 print

     *         stream.  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(fileName)} denies write

     *          access to the file

     *

     * @since  1.5

     */

    public PrintStream(String fileName) throws FileNotFoundException {

        this(false, new FileOutputStream(fileName));

    }

    /**

     * Creates a new print stream, 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 print

     *         stream.  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(fileName)} denies write

     *          access to the file

     *

     * @throws  UnsupportedEncodingException

     *          If the named charset is not supported

     *

     * @since  1.5

     */

    public PrintStream(String fileName, String csn)

        throws FileNotFoundException, UnsupportedEncodingException

    {

        // ensure charset is checked before the file is opened

        this(false, toCharset(csn), new FileOutputStream(fileName));

    }

    /**

     * Creates a new print stream, 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 print stream.  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 PrintStream(File file) throws FileNotFoundException {

        this(false, new FileOutputStream(file));

    }

    /**

     * Creates a new print stream, 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 print stream.  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 presentand {@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 PrintStream(File file, String csn)

        throws FileNotFoundException, UnsupportedEncodingException

    {

        // ensure charset is checked before the file is opened

        this(false, toCharset(csn), new FileOutputStream(file));

    }

    /** Check 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.  This is done by writing any buffered output bytes to

     * the underlying output stream and then flushing that stream.

     *

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

     */

    public void flush() {

        synchronized (this) {

            try {

                ensureOpen();

                out.flush();

            }

            catch (IOException x) {

                trouble = true;

            }

        }

    }

    private boolean closing = false; /* To avoid recursive closing */

    /**

     * Closes the stream.  This is done by flushing the stream and then closing

     * the underlying output stream.

     *

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

     */

    public void close() {

        synchronized (this) {

            if (! closing) {

                closing = true;

                try {

                    textOut.close();

                    out.close();

                }

                catch (IOException x) {

                    trouble = true;

                }

                textOut = null;

                charOut = null;

                out = null;

            }

        }

    }

    /**

     * Flushes the stream and checks its error state. The internal error state

     * is set to <code>true</code> when the underlying output stream throws an

     * <code>IOException</code> other than <code>InterruptedIOException</code>,

     * and when the <code>setError</code> method is invoked.  If an operation

     * on the underlying output stream throws an

     * <code>InterruptedIOException</code>, then the <code>PrintStream</code>

     * converts the exception back into an interrupt by doing:

     * <pre>

     *     Thread.currentThread().interrupt();

     * </pre>

     * or the equivalent.

     *

     * @return <code>true</code> if and only if this stream has encountered an

     *         <code>IOException</code> other than

     *         <code>InterruptedIOException</code>, or the

     *         <code>setError</code> method has been invoked

     */

    public boolean checkError() {

        if (out != null)

            flush();

        if (out instanceof java.io.PrintStream) {

            PrintStream ps = (PrintStream) out;

            return ps.checkError();

        }

        return trouble;

    }

    /**

     * Sets the error state of the stream to <code>true</code>.

     *

     * <p> This method will cause subsequent invocations of {@link

     * #checkError()} to return <tt>true</tt> until {@link

     * #clearError()} is invoked.

     *

     * @since JDK1.1

     */

    protected void setError() {

        trouble = true;

    }

    /**

     * Clears the internal 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 OutputStream

     */

    /**

     * Writes the specified byte to this stream.  If the byte is a newline and

     * automatic flushing is enabled then the <code>flush</code> method will be

     * invoked.

     *

     * <p> Note that the byte is written as given; to write a character that

     * will be translated according to the platform's default character

     * encoding, use the <code>print(char)</code> or <code>println(char)</code>

     * methods.

     *

     * @param  b  The byte to be written

     * @see #print(char)

     * @see #println(char)

     */

    public void write(int b) {

        try {

            synchronized (this) {

                ensureOpen();

                out.write(b);

                if ((b == '\n') && autoFlush)

                    out.flush();

            }

        }

        catch (InterruptedIOException x) {

            Thread.currentThread().interrupt();

        }

        catch (IOException x) {

            trouble = true;

        }

    }

    /**

     * Writes <code>len</code> bytes from the specified byte array starting at

     * offset <code>off</code> to this stream.  If automatic flushing is

     * enabled then the <code>flush</code> method will be invoked.

     *

     * <p> Note that the bytes will be written as given; to write characters

     * that will be translated according to the platform's default character

     * encoding, use the <code>print(char)</code> or <code>println(char)</code>

     * methods.

     *

     * @param  buf   A byte array

     * @param  off   Offset from which to start taking bytes

     * @param  len   Number of bytes to write

     */

    public void write(byte buf[], int off, int len) {

        try {

            synchronized (this) {

                ensureOpen();

                out.write(buf, off, len);

                if (autoFlush)

                    out.flush();

            }

        }

        catch (InterruptedIOException x) {

            Thread.currentThread().interrupt();

        }

        catch (IOException x) {

            trouble = true;

        }

    }

    /*

     * The following private methods on the text- and character-output streams

     * always flush the stream buffers, so that writes to the underlying byte

     * stream occur as promptly as with the original PrintStream.

     */

    private void write(char buf[]) {

        try {

            synchronized (this) {

                ensureOpen();

                textOut.write(buf);

                textOut.flushBuffer();

                charOut.flushBuffer();

                if (autoFlush) {

                    for (int i = 0; i < buf.length; i++)

                        if (buf[i] == '\n')

                            out.flush();

                }

            }

        }

        catch (InterruptedIOException x) {

            Thread.currentThread().interrupt();

        }

        catch (IOException x) {

            trouble = true;

        }

    }

    private void write(String s) {

        try {

            synchronized (this) {

                ensureOpen();

                textOut.write(s);

                textOut.flushBuffer();

                charOut.flushBuffer();

                if (autoFlush && (s.indexOf('\n') >= 0))

                    out.flush();

            }

        }

        catch (InterruptedIOException x) {

            Thread.currentThread().interrupt();

        }

        catch (IOException x) {

            trouble = true;

        }

    }

    private void newLine() {

        try {

            synchronized (this) {

                ensureOpen();

                textOut.newLine();

                textOut.flushBuffer();

                charOut.flushBuffer();

                if (autoFlush)

                    out.flush();

            }

        }

        catch (InterruptedIOException x) {

            Thread.currentThread().interrupt();

        }

        catch (IOException x) {

            trouble = true;

        }

    }

    /* Methods that do not terminate lines */

    /**

     * 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(String.valueOf(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 and then terminate 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> to be printed

     */

    public void println(boolean x) {

        synchronized (this) {

            print(x);

            newLine();

        }

    }

    /**

     * Prints a character and then terminate 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> to be printed.

     */

    public void println(char x) {

        synchronized (this) {

            print(x);

            newLine();

        }

    }

    /**

     * Prints an integer and then terminate 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> to be printed.

     */

    public void println(int x) {

        synchronized (this) {

            print(x);

            newLine();

        }

    }

    /**

     * Prints a long and then terminate the line.  This method behaves as

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

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

     *

     * @param x  a The <code>long</code> to be printed.

     */

    public void println(long x) {

        synchronized (this) {

            print(x);

            newLine();

        }

    }

    /**

     * Prints a float and then terminate 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> to be printed.

     */

    public void println(float x) {

        synchronized (this) {

            print(x);

            newLine();

        }

    }

    /**

     * Prints a double and then terminate 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> to be printed.

     */

    public void println(double x) {

        synchronized (this) {

            print(x);

            newLine();

        }

    }

    /**

     * Prints an array of characters and then terminate the line.  This method

     * behaves as though it invokes <code>{@link #print(char[])}</code> and

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

     *

     * @param x  an array of chars to print.

     */

    public void println(char x[]) {

        synchronized (this) {

            print(x);

            newLine();

        }

    }

    /**

     * Prints a String and then terminate 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> to be printed.

     */

    public void println(String x) {

        synchronized (this) {

            print(x);

            newLine();

        }

    }

    /**

     * Prints an Object and then terminate 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 (this) {

            print(s);

            newLine();

        }

    }

    /**

     * A convenience method to write a formatted string to this output stream

     * using the specified format string and arguments.

     *

     * <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 output stream

     *

     * @since  1.5

     */

    public PrintStream printf(String format, Object ... args) {

        return format(format, args);

    }

    /**

     * A convenience method to write a formatted string to this output stream

     * using the specified format string and arguments.

     *

     * <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 output stream

     *

     * @since  1.5

     */

    public PrintStream printf(Locale l, String format, Object ... args) {

        return format(l, format, args);

    }

    /**

     * Writes a formatted string to this output stream using the specified

     * format string and arguments.

     *

     * <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 output stream

     *

     * @since  1.5

     */

    public PrintStream format(String format, Object ... args) {

        try {

            synchronized (this) {

                ensureOpen();

                if ((formatter == null)

                    || (formatter.locale() != Locale.getDefault()))

                    formatter = new Formatter((Appendable) this);

                formatter.format(Locale.getDefault(), format, args);

            }

        } catch (InterruptedIOException x) {

            Thread.currentThread().interrupt();

        } catch (IOException x) {

            trouble = true;

        }

        return this;

    }

    /**

     * Writes a formatted string to this output stream using the specified

     * format string and arguments.

     *

     * @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