/*
* Copyright (c) 1996, 2016, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.io;
import java.util.Objects;
import java.util.Formatter;
import java.util.Locale;
import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;
/**
* Prints formatted representations of objects to a text-output stream. This
* class implements all of the {@code print} methods found in {@link
* PrintStream}. It does not contain methods for writing raw bytes, for which
* a program should use unencoded byte streams.
*
* <p> Unlike the {@link PrintStream} class, if automatic flushing is enabled
* it will be done only when one of the {@code println}, {@code printf}, or
* {@code format} methods is invoked, rather than whenever a newline character
* happens to be output. These methods use the platform's own notion of line
* separator rather than the newline character.
*
* <p> Methods in this class never throw I/O exceptions, although some of its
* constructors may. The client may inquire as to whether any errors have
* occurred by invoking {@link #checkError checkError()}.
*
* @author Frank Yellin
* @author Mark Reinhold
* @since 1.1
*/
public class PrintWriter extends Writer {
/**
* The underlying character-output stream of this
* {@code PrintWriter}.
*
* @since 1.2
*/
protected Writer out;
private final boolean autoFlush;
private boolean trouble = false;
private Formatter formatter;
private PrintStream psOut = null;
/**
* Returns a charset object for the given charset name.
* @throws NullPointerException is csn is null
* @throws UnsupportedEncodingException if the charset is not supported
*/
private static Charset toCharset(String csn)
throws UnsupportedEncodingException
{
Objects.requireNonNull(csn, "charsetName");
try {
return Charset.forName(csn);
} catch (IllegalCharsetNameException|UnsupportedCharsetException unused) {
// UnsupportedEncodingException should be thrown
throw new UnsupportedEncodingException(csn);
}
}
/**
* Creates a new PrintWriter, without automatic line flushing.
*
* @param out A character-output stream
*/
public PrintWriter (Writer out) {
this(out, false);
}
/**
* Creates a new PrintWriter.
*
* @param out A character-output stream
* @param autoFlush A boolean; if true, the {@code println},
* {@code printf}, or {@code format} methods will
* flush the output buffer
*/
public PrintWriter(Writer out,
boolean autoFlush) {
super(out);
this.out = out;
this.autoFlush = autoFlush;
}
/**
* Creates a new PrintWriter, without automatic line flushing, from an
* existing OutputStream. This convenience constructor creates the
* necessary intermediate OutputStreamWriter, which will convert characters
* into bytes using the default character encoding.
*
* @param out An output stream
*
* @see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream)
*/
public PrintWriter(OutputStream out) {
this(out, false);
}
/**
* Creates a new PrintWriter from an existing OutputStream. This
* convenience constructor creates the necessary intermediate
* OutputStreamWriter, which will convert characters into bytes using the
* default character encoding.
*
* @param out An output stream
* @param autoFlush A boolean; if true, the {@code println},
* {@code printf}, or {@code format} methods will
* flush the output buffer
*
* @see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream)
*/
public PrintWriter(OutputStream out, boolean autoFlush) {
this(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} if the print stream has encountered an error,
* either on the underlying output stream or during a format
* conversion.
*/
public boolean checkError() {
if (out != null) {
flush();
}
if (out instanceof java.io.PrintWriter) {
PrintWriter pw = (PrintWriter) out;
return pw.checkError();
} else if (psOut != null) {
return psOut.checkError();
}
return trouble;
}
/**
* Indicates that an error has occurred.
*
* <p> This method will cause subsequent invocations of {@link
* #checkError()} to return {@code true} until {@link
* #clearError()} is invoked.
*/
protected void setError() {
trouble = true;
}
/**
* Clears the error state of this stream.
*
* <p> This method will cause subsequent invocations of {@link
* #checkError()} to return {@code false} until another write
* operation fails and invokes {@link #setError()}.
*
* @since 1.6
*/
protected void clearError() {
trouble = false;
}
/*
* Exception-catching, synchronized output operations,
* which also implement the write() methods of Writer
*/
/**
* Writes a single character.
* @param c int specifying a character to be written.
*/
public void write(int c) {
try {
synchronized (lock) {
ensureOpen();
out.write(c);
}
}
catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
}
catch (IOException x) {
trouble = true;
}
}
/**
* Writes A Portion of an array of characters.
* @param buf Array of characters
* @param off Offset from which to start writing characters
* @param len Number of characters to write
*
* @throws IndexOutOfBoundsException
* If the values of the {@code off} and {@code len} parameters
* cause the corresponding method of the underlying {@code Writer}
* to throw an {@code IndexOutOfBoundsException}
*/
public void write(char buf[], int off, int len) {
try {
synchronized (lock) {
ensureOpen();
out.write(buf, off, len);
}
}
catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
}
catch (IOException x) {
trouble = true;
}
}
/**
* Writes an array of characters. This method cannot be inherited from the
* Writer class because it must suppress I/O exceptions.
* @param buf Array of characters to be written
*/
public void write(char buf[]) {
write(buf, 0, buf.length);
}
/**
* Writes a portion of a string.
* @param s A String
* @param off Offset from which to start writing characters
* @param len Number of characters to write
*
* @throws IndexOutOfBoundsException
* If the values of the {@code off} and {@code len} parameters
* cause the corresponding method of the underlying {@code Writer}
* to throw an {@code IndexOutOfBoundsException}
*/
public void write(String s, int off, int len) {
try {
synchronized (lock) {
ensureOpen();
out.write(s, off, len);
}
}
catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
}
catch (IOException x) {
trouble = true;
}
}
/**
* Writes a string. This method cannot be inherited from the Writer class
* because it must suppress I/O exceptions.
* @param s String to be written
*/
public void write(String s) {
write(s, 0, s.length());
}
private void newLine() {
try {
synchronized (lock) {
ensureOpen();
out.write(System.lineSeparator());
if (autoFlush)
out.flush();
}
}
catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
}
catch (IOException x) {
trouble = true;
}
}
/* Methods that do not terminate lines */
/**
* Prints a boolean value. The string produced by {@link
* java.lang.String#valueOf(boolean)} is translated into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the {@link
* #write(int)} method.
*
* @param b The {@code boolean} to be printed
*/
public void print(boolean b) {
write(String.valueOf(b));
}
/**
* Prints a character. The character is translated into one or more bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the {@link
* #write(int)} method.
*
* @param c The {@code char} to be printed
*/
public void print(char c) {
write(c);
}
/**
* Prints an integer. The string produced by {@link
* java.lang.String#valueOf(int)} is translated into bytes according
* to the platform's default character encoding, and these bytes are
* written in exactly the manner of the {@link #write(int)}
* method.
*
* @param i The {@code int} to be printed
* @see java.lang.Integer#toString(int)
*/
public void print(int i) {
write(String.valueOf(i));
}
/**
* Prints a long integer. The string produced by {@link
* java.lang.String#valueOf(long)} is translated into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the {@link #write(int)}
* method.
*
* @param l The {@code long} to be printed
* @see java.lang.Long#toString(long)
*/
public void print(long l) {
write(String.valueOf(l));
}
/**
* Prints a floating-point number. The string produced by {@link
* java.lang.String#valueOf(float)} is translated into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the {@link #write(int)}
* method.
*
* @param f The {@code float} to be printed
* @see java.lang.Float#toString(float)
*/
public void print(float f) {
write(String.valueOf(f));
}
/**
* Prints a double-precision floating-point number. The string produced by
* {@link java.lang.String#valueOf(double)} is translated into
* bytes according to the platform's default character encoding, and these
* bytes are written in exactly the manner of the {@link
* #write(int)} method.
*
* @param d The {@code double} to be printed
* @see java.lang.Double#toString(double)
*/
public void print(double d) {
write(String.valueOf(d));
}
/**
* Prints an array of characters. The characters are converted into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the {@link #write(int)}
* method.
*
* @param s The array of chars to be printed
*
* @throws NullPointerException If {@code s} is {@code null}
*/
public void print(char s[]) {
write(s);
}
/**
* Prints a string. If the argument is {@code null} then the string
* {@code "null"} is printed. Otherwise, the string's characters are
* converted into bytes according to the platform's default character
* encoding, and these bytes are written in exactly the manner of the
* {@link #write(int)} method.
*
* @param s The {@code String} to be printed
*/
public void print(String s) {
write(String.valueOf(s));
}
/**
* Prints an object. The string produced by the {@link
* java.lang.String#valueOf(Object)} method is translated into bytes
* according to the platform's default character encoding, and these bytes
* are written in exactly the manner of the {@link #write(int)}
* method.
*
* @param obj The {@code Object} to be printed
* @see java.lang.Object#toString()
*/
public void print(Object obj) {
write(String.valueOf(obj));
}
/* Methods that do terminate lines */
/**
* Terminates the current line by writing the line separator string. The
* line separator string is defined by the system property
* {@code line.separator}, and is not necessarily a single newline
* character ({@code '\n'}).
*/
public void println() {
newLine();
}
/**
* Prints a boolean value and then terminates the line. This method behaves
* as though it invokes {@link #print(boolean)} and then
* {@link #println()}.
*
* @param x the {@code boolean} value to be printed
*/
public void println(boolean x) {
synchronized (lock) {
print(x);
println();
}
}
/**
* Prints a character and then terminates the line. This method behaves as
* though it invokes {@link #print(char)} and then {@link
* #println()}.
*
* @param x the {@code char} value to be printed
*/
public void println(char x) {
synchronized (lock) {
print(x);
println();
}
}
/**
* Prints an integer and then terminates the line. This method behaves as
* though it invokes {@link #print(int)} and then {@link
* #println()}.
*
* @param x the {@code int} value to be printed
*/
public void println(int x) {
synchronized (lock) {
print(x);
println();
}
}
/**
* Prints a long integer and then terminates the line. This method behaves
* as though it invokes {@link #print(long)} and then
* {@link #println()}.
*
* @param x the {@code long} value to be printed
*/
public void println(long x) {
synchronized (lock) {
print(x);
println();
}
}
/**
* Prints a floating-point number and then terminates the line. This method
* behaves as though it invokes {@link #print(float)} and then
* {@link #println()}.
*
* @param x the {@code float} value to be printed
*/
public void println(float x) {
synchronized (lock) {
print(x);
println();
}
}
/**
* Prints a double-precision floating-point number and then terminates the
* line. This method behaves as though it invokes {@link
* #print(double)} and then {@link #println()}.
*
* @param x the {@code double} value to be printed
*/
public void println(double x) {
synchronized (lock) {
print(x);
println();
}
}
/**
* Prints an array of characters and then terminates the line. This method
* behaves as though it invokes {@link #print(char[])} and then
* {@link #println()}.
*
* @param x the array of {@code char} values to be printed
*/
public void println(char x[]) {
synchronized (lock) {
print(x);
println();
}
}
/**
* Prints a String and then terminates the line. This method behaves as
* though it invokes {@link #print(String)} and then
* {@link #println()}.
*
* @param x the {@code String} value to be printed
*/
public void println(String x) {
synchronized (lock) {
print(x);
println();
}
}
/**
* Prints an Object and then terminates the line. This method calls
* at first String.valueOf(x) to get the printed object's string value,
* then behaves as
* though it invokes {@link #print(String)} and then
* {@link #println()}.
*
* @param x The {@code Object} to be printed.
*/
public void println(Object x) {
String s = String.valueOf(x);
synchronized (lock) {
print(s);
println();
}
}
/**
* A convenience method to write a formatted string to this writer using
* the specified format string and arguments. If automatic flushing is
* enabled, calls to this method will flush the output buffer.
*
* <p> An invocation of this method of the form
* {@code out.printf(format, args)}
* behaves in exactly the same way as the invocation
*
* <pre>{@code
* out.format(format, args)
* }</pre>
*
* @param format
* A format string as described in <a
* href="../util/Formatter.html#syntax">Format string syntax</a>.
*
* @param args
* Arguments referenced by the format specifiers in the format
* string. If there are more arguments than format specifiers, the
* extra arguments are ignored. The number of arguments is
* variable and may be zero. The maximum number of arguments is
* limited by the maximum dimension of a Java array as defined by
* <cite>The Java™ Virtual Machine Specification</cite>.
* The behaviour on a
* {@code null} argument depends on the <a
* href="../util/Formatter.html#syntax">conversion</a>.
*
* @throws java.util.IllegalFormatException
* If a format string contains an illegal syntax, a format
* specifier that is incompatible with the given arguments,
* insufficient arguments given the format string, or other
* illegal conditions. For specification of all possible
* formatting errors, see the <a
* href="../util/Formatter.html#detail">Details</a> section of the
* formatter class specification.
*
* @throws NullPointerException
* If the {@code format} is {@code null}
*
* @return This writer
*
* @since 1.5
*/
public PrintWriter printf(String format, Object ... args) {
return format(format, args);
}
/**
* A convenience method to write a formatted string to this writer using
* the specified format string and arguments. If automatic flushing is
* enabled, calls to this method will flush the output buffer.
*
* <p> An invocation of this method of the form
* {@code out.printf(l, format, args)}
* behaves in exactly the same way as the invocation
*
* <pre>{@code
* out.format(l, format, args)
* }</pre>
*
* @param l
* The {@linkplain java.util.Locale locale} to apply during
* formatting. If {@code l} is {@code null} then no localization
* is applied.
*
* @param format
* A format string as described in <a
* href="../util/Formatter.html#syntax">Format string syntax</a>.
*
* @param args
* Arguments referenced by the format specifiers in the format
* string. If there are more arguments than format specifiers, the
* extra arguments are ignored. The number of arguments is
* variable and may be zero. The maximum number of arguments is
* limited by the maximum dimension of a Java array as defined by
* <cite>The Java™ Virtual Machine Specification</cite>.
* The behaviour on a
* {@code null} argument depends on the <a
* href="../util/Formatter.html#syntax">conversion</a>.
*
* @throws java.util.IllegalFormatException
* If a format string contains an illegal syntax, a format
* specifier that is incompatible with the given arguments,
* insufficient arguments given the format string, or other
* illegal conditions. For specification of all possible
* formatting errors, see the <a
* href="../util/Formatter.html#detail">Details</a> section of the
* formatter class specification.
*
* @throws NullPointerException
* If the {@code format} is {@code null}
*
* @return This writer
*
* @since 1.5
*/
public PrintWriter printf(Locale l, String format, Object ... args) {
return format(l, format, args);
}
/**
* Writes a formatted string to this writer using the specified format
* string and arguments. If automatic flushing is enabled, calls to this
* method will flush the output buffer.
*
* <p> The locale always used is the one returned by {@link
* java.util.Locale#getDefault() Locale.getDefault()}, regardless of any
* previous invocations of other formatting methods on this object.
*
* @param format
* A format string as described in <a
* href="../util/Formatter.html#syntax">Format string syntax</a>.
*
* @param args
* Arguments referenced by the format specifiers in the format
* string. If there are more arguments than format specifiers, the
* extra arguments are ignored. The number of arguments is
* variable and may be zero. The maximum number of arguments is
* limited by the maximum dimension of a Java array as defined by
* <cite>The Java™ Virtual Machine Specification</cite>.
* The behaviour on a
* {@code null} argument depends on the <a
* href="../util/Formatter.html#syntax">conversion</a>.
*
* @throws java.util.IllegalFormatException
* If a format string contains an illegal syntax, a format
* specifier that is incompatible with the given arguments,
* insufficient arguments given the format string, or other
* illegal conditions. For specification of all possible
* formatting errors, see the <a
* href="../util/Formatter.html#detail">Details</a> section of the
* Formatter class specification.
*
* @throws NullPointerException
* If the {@code format} is {@code null}
*
* @return This writer
*
* @since 1.5
*/
public PrintWriter format(String format, Object ... args) {
try {
synchronized (lock) {
ensureOpen();
if ((formatter == null)
|| (formatter.locale() != Locale.getDefault()))
formatter = new Formatter(this);
formatter.format(Locale.getDefault(), format, args);
if (autoFlush)
out.flush();
}
} catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
} catch (IOException x) {
trouble = true;
}
return this;
}
/**
* Writes a formatted string to this writer using the specified format
* string and arguments. If automatic flushing is enabled, calls to this
* method will flush the output buffer.
*
* @param l
* The {@linkplain java.util.Locale locale} to apply during
* formatting. If {@code l} is {@code null} then no localization
* is applied.
*
* @param format
* A format string as described in <a
* href="../util/Formatter.html#syntax">Format string syntax</a>.
*
* @param args
* Arguments referenced by the format specifiers in the format
* string. If there are more arguments than format specifiers, the
* extra arguments are ignored. The number of arguments is
* variable and may be zero. The maximum number of arguments is
* limited by the maximum dimension of a Java array as defined by
* <cite>The Java™ Virtual Machine Specification</cite>.
* The behaviour on a
* {@code null} argument depends on the <a
* href="../util/Formatter.html#syntax">conversion</a>.
*
* @throws java.util.IllegalFormatException
* If a format string contains an illegal syntax, a format
* specifier that is incompatible with the given arguments,
* insufficient arguments given the format string, or other
* illegal conditions. For specification of all possible
* formatting errors, see the <a
* href="../util/Formatter.html#detail">Details</a> section of the
* formatter class specification.
*
* @throws NullPointerException
* If the {@code format} is {@code null}
*
* @return This writer
*
* @since 1.5
*/
public PrintWriter format(Locale l, String format, Object ... args) {
try {
synchronized (lock) {
ensureOpen();
if ((formatter == null) || (formatter.locale() != l))
formatter = new Formatter(this, l);
formatter.format(l, format, args);
if (autoFlush)
out.flush();
}
} catch (InterruptedIOException x) {
Thread.currentThread().interrupt();
} catch (IOException x) {
trouble = true;
}
return this;
}
/**
* Appends the specified character sequence to this writer.
*
* <p> An invocation of this method of the form {@code out.append(csq)}
* behaves in exactly the same way as the invocation
*
* <pre>{@code
* out.write(csq.toString())
* }</pre>
*
* <p> Depending on the specification of {@code toString} for the
* character sequence {@code csq}, the entire sequence may not be
* appended. For instance, invoking the {@code toString} method of a
* character buffer will return a subsequence whose content depends upon
* the buffer's position and limit.
*
* @param csq
* The character sequence to append. If {@code csq} is
* {@code null}, then the four characters {@code "null"} are
* appended to this writer.
*
* @return This writer
*
* @since 1.5
*/
public PrintWriter append(CharSequence csq) {
write(String.valueOf(csq));
return this;
}
/**
* Appends a subsequence of the specified character sequence to this writer.
*
* <p> An invocation of this method of the form
* {@code out.append(csq, start, end)}
* when {@code csq} is not {@code null}, behaves in
* exactly the same way as the invocation
*
* <pre>{@code
* out.write(csq.subSequence(start, end).toString())
* }</pre>
*
* @param csq
* The character sequence from which a subsequence will be
* appended. If {@code csq} is {@code null}, then characters
* will be appended as if {@code csq} contained the four
* characters {@code "null"}.
*
* @param start
* The index of the first character in the subsequence
*
* @param end
* The index of the character following the last character in the
* subsequence
*
* @return This writer
*
* @throws IndexOutOfBoundsException
* If {@code start} or {@code end} are negative, {@code start}
* is greater than {@code end}, or {@code end} is greater than
* {@code csq.length()}
*
* @since 1.5
*/
public PrintWriter append(CharSequence csq, int start, int end) {
if (csq == null) csq = "null";
return append(csq.subSequence(start, end));
}
/**
* Appends the specified character to this writer.
*
* <p> An invocation of this method of the form {@code out.append(c)}
* behaves in exactly the same way as the invocation
*
* <pre>{@code
* out.write(c)
* }</pre>
*
* @param c
* The 16-bit character to append
*
* @return This writer
*
* @since 1.5
*/
public PrintWriter append(char c) {
write(c);
return this;
}
}