java.io

Class PrintWriter

Implemented Interfaces:
Appendable, AutoCloseable, Closeable, Flushable

public class PrintWriter
extends Writer

This class prints Java primitive values and objects to a stream as text. None of the methods in this class throw an exception. However, errors can be detected by calling the checkError() method. Additionally, this stream can be designated as "autoflush" when created so that any writes are automatically flushed to the underlying output sink whenever one of the println methods is called. (Note that this differs from the PrintStream class which also auto-flushes when it encounters a newline character in the chars written).

Field Summary

protected Writer
out
This is the underlying Writer we are sending output to

Fields inherited from class java.io.Writer

lock

Constructor Summary

PrintWriter(File file)
This initializes a new PrintWriter object to write to the specified file.
PrintWriter(File file, String enc)
This initializes a new PrintWriter object to write to the specified file.
PrintWriter(OutputStream out)
This method initializes a new PrintWriter object to write to the specified OutputStream.
PrintWriter(OutputStream out, boolean autoflush)
This method initializes a new PrintWriter object to write to the specified OutputStream.
PrintWriter(Writer wr)
This method intializes a new PrintWriter object to write to the specified output sink.
PrintWriter(Writer wr, boolean autoflush)
This method intializes a new PrintWriter object to write to the specified output sink.
PrintWriter(String file)
This initializes a new PrintWriter object to write to the specified file.
PrintWriter(String file, String enc)
This initializes a new PrintWriter object to write to the specified file.

Method Summary

PrintWriter
append(char c)
PrintWriter
append(CharSequence cs)
PrintWriter
append(CharSequence cs, int start, int end)
boolean
checkError()
This method checks to see if an error has occurred on this stream.
void
close()
This method closes this stream and all underlying streams.
void
flush()
This method flushes any buffered chars to the underlying stream and then flushes that stream as well.
PrintWriter
format(String format, java.lang.Object... args)
PrintWriter
format(Locale locale, String format, java.lang.Object... args)
void
print(boolean bool)
This methods prints a boolean value to the stream.
void
print(char ch)
This method prints a char to the stream.
void
print(char[] charArray)
This method prints an array of characters to the stream.
void
print(double dnum)
This method prints a double to the stream.
void
print(float fnum)
This method prints a float to the stream.
void
print(int inum)
This method prints an integer to the stream.
void
print(Object obj)
This method prints an Object to the stream.
void
print(String str)
This method prints a String to the stream.
void
print(long lnum)
This method prints a long to the stream.
PrintWriter
printf(String format, java.lang.Object... args)
PrintWriter
printf(Locale locale, String format, java.lang.Object... args)
void
println()
This method prints a line separator sequence to the stream.
void
println(boolean bool)
This methods prints a boolean value to the stream.
void
println(char ch)
This method prints a char to the stream.
void
println(char[] charArray)
This method prints an array of characters to the stream.
void
println(double dnum)
This method prints a double to the stream.
void
println(float fnum)
This method prints a float to the stream.
void
println(int inum)
This method prints an integer to the stream.
void
println(Object obj)
This method prints an Object to the stream.
void
println(String str)
This method prints a String to the stream.
void
println(long lnum)
This method prints a long to the stream.
protected void
setError()
This method can be called by subclasses to indicate that an error has occurred and should be reported by checkError.
void
write(char[] charArray)
This method write all the chars in the specified array to the output.
void
write(char[] charArray, int offset, int count)
This method writes count chars from the specified array starting at index offset into the array.
void
write(int ch)
This method writes a single char to the stream.
void
write(String str)
This method writes the contents of the specified String to the underlying stream.
void
write(String str, int offset, int count)
This method writes count chars from the specified String to the output starting at character position offset into the String

Methods inherited from class java.io.Writer

append, append, append, close, flush, write, write, write, write, write

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

out

protected Writer out
This is the underlying Writer we are sending output to

Constructor Details

PrintWriter

public PrintWriter(File file)
            throws FileNotFoundException
This initializes a new PrintWriter object to write to the specified file. It creates a FileOutputStream object and wraps it in an OutputStreamWriter using the default encoding.
Parameters:
file - the file to write to
Throws:
FileNotFoundException - if the file cannot be written or created
Since:
1.5

PrintWriter

public PrintWriter(File file,
                   String enc)
            throws FileNotFoundException,
                   UnsupportedEncodingException
This initializes a new PrintWriter object to write to the specified file. It creates a FileOutputStream object and wraps it in an OutputStreamWriter using the specified encoding.
Parameters:
file - the file to write to
enc - the encoding to use
Throws:
FileNotFoundException - if the file cannot be written or created
UnsupportedEncodingException - if the encoding is not supported
Since:
1.5

PrintWriter

public PrintWriter(OutputStream out)
This method initializes a new PrintWriter object to write to the specified OutputStream. Characters will be converted to chars using the system default encoding. Auto-flush functionality will not be enabled.
Parameters:
out - The OutputStream to write to

PrintWriter

public PrintWriter(OutputStream out,
                   boolean autoflush)
This method initializes a new PrintWriter object to write to the specified OutputStream. Characters will be converted to chars using the system default encoding. This form of the constructor allows auto-flush functionality to be enabled if desired
Parameters:
out - The OutputStream to write to
autoflush - true to flush the stream after every println call, false otherwise.

PrintWriter

public PrintWriter(Writer wr)
This method intializes a new PrintWriter object to write to the specified output sink. The form of the constructor does not enable auto-flush functionality.
Parameters:
wr - The Writer to write to.

PrintWriter

public PrintWriter(Writer wr,
                   boolean autoflush)
This method intializes a new PrintWriter object to write to the specified output sink. This constructor also allows "auto-flush" functionality to be specified where the stream will be flushed after every line is terminated or newline character is written.
Parameters:
wr - The Writer to write to.
autoflush - true to flush the stream after every line, false otherwise

PrintWriter

public PrintWriter(String file)
            throws FileNotFoundException
This initializes a new PrintWriter object to write to the specified file. It creates a FileOutputStream object and wraps it in an OutputStreamWriter using the default encoding.
Parameters:
file - name of the file to write to
Throws:
FileNotFoundException - if the file cannot be written or created
Since:
1.5

PrintWriter

public PrintWriter(String file,
                   String enc)
            throws FileNotFoundException,
                   UnsupportedEncodingException
This initializes a new PrintWriter object to write to the specified file. It creates a FileOutputStream object and wraps it in an OutputStreamWriter using the specified encoding.
Parameters:
file - name of the file to write to
enc - the encoding to use
Throws:
FileNotFoundException - if the file cannot be written or created
UnsupportedEncodingException - if the encoding is not supported
Since:
1.5

Method Details

append

public PrintWriter append(char c)
Specified by:
append in interface Appendable
Overrides:
append in interface Writer
Since:
1.5

append

public PrintWriter append(CharSequence cs)
Specified by:
append in interface Appendable
Overrides:
append in interface Writer
Since:
1.5

append

public PrintWriter append(CharSequence cs,
                          int start,
                          int end)
Specified by:
append in interface Appendable
Overrides:
append in interface Writer
Since:
1.5

checkError

public boolean checkError()
This method checks to see if an error has occurred on this stream. Note that once an error has occurred, this method will continue to report true forever for this stream. Before checking for an error condition, this method flushes the stream.
Returns:
true if an error has occurred, false otherwise

close

public void close()
This method closes this stream and all underlying streams.
Specified by:
close in interface Closeable
close in interface AutoCloseable
Overrides:
close in interface Writer

flush

public void flush()
This method flushes any buffered chars to the underlying stream and then flushes that stream as well.
Specified by:
flush in interface Flushable
Overrides:
flush in interface Writer

format

public PrintWriter format(String format,
                          java.lang.Object... args)
Since:
1.5

format

public PrintWriter format(Locale locale,
                          String format,
                          java.lang.Object... args)
Since:
1.5

print

public void print(boolean bool)
This methods prints a boolean value to the stream. true values are printed as "true" and false values are printed as "false".
Parameters:
bool - The boolean value to print

print

public void print(char ch)
This method prints a char to the stream. The actual value printed is determined by the character encoding in use.
Parameters:
ch - The char value to be printed

print

public void print(char[] charArray)
This method prints an array of characters to the stream. The actual value printed depends on the system default encoding.
Parameters:
charArray - The array of characters to print.

print

public void print(double dnum)
This method prints a double to the stream. The value printed is determined using the String.valueOf() method.
Parameters:
dnum - The double value to be printed

print

public void print(float fnum)
This method prints a float to the stream. The value printed is determined using the String.valueOf() method.
Parameters:
fnum - The float value to be printed

print

public void print(int inum)
This method prints an integer to the stream. The value printed is determined using the String.valueOf() method.
Parameters:
inum - The int value to be printed

print

public void print(Object obj)
This method prints an Object to the stream. The actual value printed is determined by calling the String.valueOf() method.
Parameters:
obj - The Object to print.

print

public void print(String str)
This method prints a String to the stream. The actual value printed depends on the system default encoding.
Parameters:
str - The String to print.

print

public void print(long lnum)
This method prints a long to the stream. The value printed is determined using the String.valueOf() method.
Parameters:
lnum - The long value to be printed

printf

public PrintWriter printf(String format,
                          java.lang.Object... args)
Since:
1.5

printf

public PrintWriter printf(Locale locale,
                          String format,
                          java.lang.Object... args)
Since:
1.5

println

public void println()
This method prints a line separator sequence to the stream. The value printed is determined by the system property line.separator and is not necessarily the Unix '\n' newline character.

println

public void println(boolean bool)
This methods prints a boolean value to the stream. true values are printed as "true" and false values are printed as "false". This method prints a line termination sequence after printing the value.
Parameters:
bool - The boolean value to print

println

public void println(char ch)
This method prints a char to the stream. The actual value printed is determined by the character encoding in use. This method prints a line termination sequence after printing the value.
Parameters:
ch - The char value to be printed

println

public void println(char[] charArray)
This method prints an array of characters to the stream. The actual value printed depends on the system default encoding. This method prints a line termination sequence after printing the value.
Parameters:
charArray - The array of characters to print.

println

public void println(double dnum)
This method prints a double to the stream. The value printed is determined using the String.valueOf() method. This method prints a line termination sequence after printing the value.
Parameters:
dnum - The double value to be printed

println

public void println(float fnum)
This method prints a float to the stream. The value printed is determined using the String.valueOf() method. This method prints a line termination sequence after printing the value.
Parameters:
fnum - The float value to be printed

println

public void println(int inum)
This method prints an integer to the stream. The value printed is determined using the String.valueOf() method. This method prints a line termination sequence after printing the value.
Parameters:
inum - The int value to be printed

println

public void println(Object obj)
This method prints an Object to the stream. The actual value printed is determined by calling the String.valueOf() method. This method prints a line termination sequence after printing the value.
Parameters:
obj - The Object to print.

println

public void println(String str)
This method prints a String to the stream. The actual value printed depends on the system default encoding. This method prints a line termination sequence after printing the value.
Parameters:
str - The String to print.

println

public void println(long lnum)
This method prints a long to the stream. The value printed is determined using the String.valueOf() method. This method prints a line termination sequence after printing the value.
Parameters:
lnum - The long value to be printed

setError

protected void setError()
This method can be called by subclasses to indicate that an error has occurred and should be reported by checkError.

write

public void write(char[] charArray)
This method write all the chars in the specified array to the output.
Overrides:
write in interface Writer
Parameters:
charArray - The array of characters to write

write

public void write(char[] charArray,
                  int offset,
                  int count)
This method writes count chars from the specified array starting at index offset into the array.
Overrides:
write in interface Writer
Parameters:
charArray - The array of chars to write
offset - The index into the array to start writing from
count - The number of chars to write

write

public void write(int ch)
This method writes a single char to the stream.
Overrides:
write in interface Writer
Parameters:
ch - The char to be written, passed as a int

write

public void write(String str)
This method writes the contents of the specified String to the underlying stream.
Overrides:
write in interface Writer
Parameters:
str - The String to write

write

public void write(String str,
                  int offset,
                  int count)
This method writes count chars from the specified String to the output starting at character position offset into the String
Overrides:
write in interface Writer
Parameters:
str - The String to write chars from
offset - The offset into the String to start writing from
count - The number of chars to write.

PrintWriter.java -- prints primitive values and objects to a stream as text Copyright (C) 1998, 1999, 2000, 2001, 2005 Free Software Foundation This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath 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 for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.