java.io.PrintStream Maven / Gradle / Ivy
/*
* 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.nio.charset.Charset;
import java.util.Arrays;
/**
* A PrintStream 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 PrintStream never throws an
* IOException; instead, exceptional situations merely set an
* internal flag that can be tested via the checkError method.
* Optionally, a PrintStream can be created so as to flush
* automatically; this means that the flush method is
* automatically invoked after a byte array is written, one of the
* println methods is invoked, or a newline character or byte
* ('\n') is written.
*
* All characters printed by a PrintStream are converted into
* bytes using the platform's default character encoding. The {@link
* PrintWriter} 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 requireNonNull(T obj, String message) {
if (obj == null)
throw new NullPointerException(message);
return obj;
}
/* Private constructors */
private PrintStream(boolean autoFlush, OutputStream out) {
super(out);
this.autoFlush = autoFlush;
this.charOut = new OutputStreamWriter(this);
this.textOut = new BufferedWriter(charOut);
}
static final class Formatter {
}
static Charset toCharset(String ch) throws UnsupportedEncodingException {
if (!"UTF-8".equals(ch)) {
throw new UnsupportedEncodingException();
}
return null;
}
private PrintStream(boolean autoFlush, OutputStream out, Charset charset) {
super(out);
this.autoFlush = autoFlush;
this.charOut = new OutputStreamWriter(this);
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
* println methods is invoked, or a newline
* character or byte ('\n') 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
* println methods is invoked, or a newline
* character or byte ('\n') is written
* @param encoding The name of a supported
*
* character encoding
*
* @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 {
super(null);
throw new FileNotFoundException();
}
/**
* 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
{
super(null);
throw new FileNotFoundException();
}
/**
* 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 {
super(null);
throw new FileNotFoundException();
}
/**
* 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
{
super(null);
throw new FileNotFoundException();
}
/** 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 true when the underlying output stream throws an
* IOException other than InterruptedIOException,
* and when the setError method is invoked. If an operation
* on the underlying output stream throws an
* InterruptedIOException, then the PrintStream
* converts the exception back into an interrupt by doing:
*
* Thread.currentThread().interrupt();
*
* or the equivalent.
*
* @return true if and only if this stream has encountered an
* IOException other than
* InterruptedIOException, or the
* setError 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 true.
*
* This method will cause subsequent invocations of {@link
* #checkError()} to return true until {@link
* #clearError()} is invoked.
*
* @since JDK1.1
*/
protected void setError() {
trouble = true;
}
/**
* Clears the internal error state of this stream.
*
*
This method will cause subsequent invocations of {@link
* #checkError()} to return 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 OutputStream
*/
/**
* Writes the specified byte to this stream. If the byte is a newline and
* automatic flushing is enabled then the flush method will be
* invoked.
*
*
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 print(char) or println(char)
* 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 len bytes from the specified byte array starting at
* offset off to this stream. If automatic flushing is
* enabled then the flush method will be invoked.
*
*
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 print(char) or println(char)
* 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 {@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 boolean 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
* {@link #write(int)} method.
*
* @param c The char to be printed
*/
public void print(char c) {
write(String.valueOf(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 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 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 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 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 s is 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
* {@link #write(int)} method.
*
* @param s The String to be printed
*/
public void print(String s) {
if (s == null) {
s = "null";
}
write(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 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').
*/
public void println() {
newLine();
}
/**
* Prints a boolean and then terminate the line. This method behaves as
* though it invokes {@link #print(boolean)} and then
* {@link #println()}.
*
* @param x The boolean 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 {@link #print(char)} and then
* {@link #println()}.
*
* @param x The char 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 {@link #print(int)} and then
* {@link #println()}.
*
* @param x The int 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 {@link #print(long)} and then
* {@link #println()}.
*
* @param x a The long 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 {@link #print(float)} and then
* {@link #println()}.
*
* @param x The float 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 {@link #print(double)} and then
* {@link #println()}.
*
* @param x The double 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 {@link #print(char[])} and
* then {@link #println()}.
*
* @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 {@link #print(String)} and then
* {@link #println()}.
*
* @param x The String 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 {@link #print(String)} and then
* {@link #println()}.
*
* @param x The Object 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.
*
*
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)
*
* @param format
* A format string as described in Format string syntax
*
* @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
* 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.
*
* @throws NullPointerException
* If the format is null
*
* @return This output stream
*
* @since 1.5
*/
public PrintStream printf(String format, Object ... args) {
append(format).append(Arrays.toString(args));
return this;
}
/**
* A convenience method to write a formatted string to this output stream
* using the specified format string and arguments.
*
* 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)
*
* @param l
* The {@linkplain java.util.Locale locale} to apply during
* formatting. If l is null then no localization
* is applied.
*
* @param format
* A format string as described in Format string syntax
*
* @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
* 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.
*
* @throws NullPointerException
* If the format is null
*
* @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.
*
* 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 Format string syntax
*
* @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
* 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.
*
* @throws NullPointerException
* If the format is null
*
* @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 l is null then no localization
* is applied.
*
* @param format
* A format string as described in Format string syntax
*
* @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
* 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.
*
* @throws NullPointerException
* If the format is null
*
* @return This output stream
*
* @since 1.5
*/
//// public PrintStream format(Locale l, String format, Object ... args) {
//// try {
//// synchronized (this) {
//// ensureOpen();
//// if ((formatter == null)
//// || (formatter.locale() != l))
//// formatter = new Formatter(this, l);
//// formatter.format(l, format, args);
//// }
//// } catch (InterruptedIOException x) {
//// Thread.currentThread().interrupt();
//// } catch (IOException x) {
//// trouble = true;
//// }
//// return this;
//// }
/**
* Appends the specified character sequence to this output stream.
*
*
An invocation of this method of the form out.append(csq)
* behaves in exactly the same way as the invocation
*
*
* out.print(csq.toString())
*
* Depending on the specification of toString for the
* character sequence csq, the entire sequence may not be
* appended. For instance, invoking then 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 csq is
* null, then the four characters "null" are
* appended to this output stream.
*
* @return This output stream
*
* @since 1.5
*/
public PrintStream append(CharSequence csq) {
if (csq == null)
print("null");
else
print(csq.toString());
return this;
}
/**
* Appends a subsequence of the specified character sequence to this output
* stream.
*
*
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.print(csq.subSequence(start, end).toString())
*
* @param 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".
*
* @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 output stream
*
* @throws IndexOutOfBoundsException
* If start or end are negative, start
* is greater than end, or end is greater than
* csq.length()
*
* @since 1.5
*/
public PrintStream append(CharSequence csq, int start, int end) {
CharSequence cs = (csq == null ? "null" : csq);
write(cs.subSequence(start, end).toString());
return this;
}
/**
* Appends the specified character to this output stream.
*
* An invocation of this method of the form out.append(c)
* behaves in exactly the same way as the invocation
*
*
* out.print(c)
*
* @param c
* The 16-bit character to append
*
* @return This output stream
*
* @since 1.5
*/
public PrintStream append(char c) {
print(c);
return this;
}
}