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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 print methods found in PrintStream. It does not contain methods for writing raw bytes, for which a program should use unencoded byte streams.

Unlike the PrintStream class, if automatic flushing is enabled it will be done only when one of the println, printf, or 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.

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 checkError().

This class always replaces malformed and unmappable character sequences with the charset's default replacement string. The CharsetEncoder class should be used when more control over the encoding process is required.

Author: Frank Yellin, Mark Reinhold
Since: 1.1
/** * 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 PrintWriter.
Since:1.2
/** * 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:
/** * 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.
Params:
  • out – A character-output stream
/** * 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.
Params:
  • out – A character-output stream
  • autoFlush – A boolean; if true, the println, printf, or format methods will flush the output buffer
/** * 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.
Params:
  • out – An output stream
See Also:
/** * 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.
Params:
  • out – An output stream
  • autoFlush – A boolean; if true, the println, printf, or format methods will flush the output buffer
See Also:
/** * 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.
Params:
  • out – An output stream
  • autoFlush – A boolean; if true, the println, printf, or format methods will flush the output buffer
  • charset – A charset
Since:10
/** * 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 OutputStreamWriter, which will encode characters using the default charset for this instance of the Java virtual machine.
Params:
  • 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
  • SecurityException – If a security manager is present and checkWrite(fileName) denies write access to the file
Since: 1.5
/** * 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 OutputStreamWriter, which will encode characters using the provided charset.
Params:
  • 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.
  • csn – The name of a supported charset
Throws:
Since: 1.5
/** * 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 OutputStreamWriter, which will encode characters using the provided charset.
Params:
  • 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.
  • charset – A charset
Throws:
Since: 10
/** * 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 OutputStreamWriter, which will encode characters using the default charset for this instance of the Java virtual machine.
Params:
  • 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
  • SecurityException – If a security manager is present and checkWrite(file.getPath()) denies write access to the file
Since: 1.5
/** * 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 OutputStreamWriter, which will encode characters using the provided charset.
Params:
  • 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.
  • csn – The name of a supported charset
Throws:
Since: 1.5
/** * 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 OutputStreamWriter, which will encode characters using the provided charset.
Params:
  • 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.
  • charset – A charset
Throws:
Since: 10
/** * 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
/** 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 Also:
  • checkError()
/** * 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 Also:
  • checkError()
/** * 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.
Returns:true if the print stream has encountered an error, either on the underlying output stream or during a format conversion.
/** * 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.

This method will cause subsequent invocations of checkError() to return true until clearError() is invoked.

/** * 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.

This method will cause subsequent invocations of checkError() to return false until another write operation fails and invokes setError().

Since:1.6
/** * 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.
Params:
  • c – int specifying a character to be written.
/** * 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.
Params:
  • buf – Array of characters
  • off – Offset from which to start writing characters
  • len – Number of characters to write
Throws:
  • IndexOutOfBoundsException – If the values of the off and len parameters cause the corresponding method of the underlying Writer to throw an IndexOutOfBoundsException
/** * 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.
Params:
  • buf – Array of characters to be written
/** * 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.
Params:
  • s – A String
  • off – Offset from which to start writing characters
  • len – Number of characters to write
Throws:
  • IndexOutOfBoundsException – If the values of the off and len parameters cause the corresponding method of the underlying Writer to throw an IndexOutOfBoundsException
/** * 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.
Params:
  • s – String to be written
/** * 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 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 write(int) method.
Params:
  • b – The boolean to be printed
/** * 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 write(int) method.
Params:
  • c – The char to be printed
/** * 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 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 write(int) method.
Params:
  • i – The int to be printed
See Also:
/** * 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 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 write(int) method.
Params:
  • l – The long to be printed
See Also:
/** * 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 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 write(int) method.
Params:
  • f – The float to be printed
See Also:
/** * 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 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 write(int) method.
Params:
  • d – The double to be printed
See Also:
/** * 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 write(int) method.
Params:
  • s – The array of chars to be printed
Throws:
/** * 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 null then the string "null" is printed. Otherwise, the string's characters are converted into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the write(int) method.
Params:
  • s – The String to be printed
/** * 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 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 write(int) method.
Params:
  • obj – The Object to be printed
See Also:
/** * 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 line.separator, and is not necessarily a single newline character ('\n').
/** * 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 print(boolean) and then println().
Params:
  • x – the boolean value to be printed
/** * 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 print(char) and then println().
Params:
  • x – the char value to be printed
/** * 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 print(int) and then println().
Params:
  • x – the int value to be printed
/** * 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 print(long) and then println().
Params:
  • x – the long value to be printed
/** * 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 print(float) and then println().
Params:
  • x – the float value to be printed
/** * 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 print(double) and then println().
Params:
  • x – the double value to be printed
/** * 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 print(char[]) and then println().
Params:
  • x – the array of char values to be printed
/** * 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 print(String) and then println().
Params:
  • x – the String value to be printed
/** * 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 print(String) and then println().
Params:
  • x – The Object to be printed.
/** * 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.

An invocation of this method of the form out.printf(format, args) behaves in exactly the same way as the invocation


    out.format(format, args)
Params:
  • format – A format string as described in Format string syntax.
  • args – Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
Throws:
  • IllegalFormatException – If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.
  • NullPointerException – If the format is null
Returns: This writer
Since: 1.5
/** * 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.

An invocation of this method of the form out.printf(l, format, args) behaves in exactly the same way as the invocation


    out.format(l, format, args)
Params:
  • l – The locale to apply during formatting. If l is null then no localization is applied.
  • format – A format string as described in Format string syntax.
  • args – Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
Throws:
  • IllegalFormatException – If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.
  • NullPointerException – If the format is null
Returns: This writer
Since: 1.5
/** * 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.

The locale always used is the one returned by Locale.getDefault(), regardless of any previous invocations of other formatting methods on this object.

Params:
  • format – A format string as described in Format string syntax.
  • args – Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
Throws:
  • IllegalFormatException – If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the Formatter class specification.
  • NullPointerException – If the format is null
Returns: This writer
Since: 1.5
/** * 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.
Params:
  • l – The locale to apply during formatting. If l is null then no localization is applied.
  • format – A format string as described in Format string syntax.
  • args – Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
Throws:
  • IllegalFormatException – If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.
  • NullPointerException – If the format is null
Returns: This writer
Since: 1.5
/** * 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.

An invocation of this method of the form out.append(csq) behaves in exactly the same way as the invocation


    out.write(csq.toString())

Depending on the specification of toString for the character sequence csq, the entire sequence may not be appended. For instance, invoking the toString method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.

Params:
  • csq – The character sequence to append. If csq is null, then the four characters "null" are appended to this writer.
Returns: This writer
Since: 1.5
/** * 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.

An invocation of this method of the form out.append(csq, start, end) when csq is not null, behaves in exactly the same way as the invocation


    out.write(csq.subSequence(start, end).toString())
Params:
  • csq – The character sequence from which a subsequence will be appended. If csq is null, then characters will be appended as if csq contained the four characters "null".
  • start – The index of the first character in the subsequence
  • end – The index of the character following the last character in the subsequence
Throws:
Returns: This writer
Since: 1.5
/** * 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.

An invocation of this method of the form out.append(c) behaves in exactly the same way as the invocation


    out.write(c)
Params:
  • c – The 16-bit character to append
Returns: This writer
Since:1.5
/** * 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; } }