public
abstract
class
Writer
extends Object
implements
Appendable,
Closeable,
Flushable
java.lang.Object | |
↳ | java.io.Writer |
Known Direct Subclasses |
Known Indirect Subclasses |
Abstract class for writing to character streams. The only methods that a subclass must implement are write(char[], int, int), flush(), and close(). Most subclasses, however, will override some of the methods defined here in order to provide higher efficiency, additional functionality, or both.
See also:
Fields | |
---|---|
protected
Object |
lock
The object used to synchronize operations on this stream. |
Protected constructors | |
---|---|
Writer()
Creates a new character-stream writer whose critical sections will synchronize on the writer itself. |
|
Writer(Object lock)
Creates a new character-stream writer whose critical sections will synchronize on the given object. |
Public methods | |
---|---|
Writer
|
append(char c)
Appends the specified character to this writer. |
Writer
|
append(CharSequence csq, int start, int end)
Appends a subsequence of the specified character sequence to this writer. |
Writer
|
append(CharSequence csq)
Appends the specified character sequence to this writer. |
abstract
void
|
close()
Closes the stream, flushing it first. |
abstract
void
|
flush()
Flushes the stream. |
void
|
write(String str)
Writes a string. |
void
|
write(int c)
Writes a single character. |
void
|
write(String str, int off, int len)
Writes a portion of a string. |
abstract
void
|
write(char[] cbuf, int off, int len)
Writes a portion of an array of characters. |
void
|
write(char[] cbuf)
Writes an array of characters. |
Inherited methods | |
---|---|
From
class
java.lang.Object
| |
From
interface
java.lang.Appendable
| |
From
interface
java.io.Closeable
| |
From
interface
java.io.Flushable
| |
From
interface
java.lang.AutoCloseable
|
Object lock
The object used to synchronize operations on this stream. For efficiency, a character-stream object may use an object other than itself to protect critical sections. A subclass should therefore use the object in this field rather than this or a synchronized method.
Writer ()
Creates a new character-stream writer whose critical sections will synchronize on the writer itself.
Writer (Object lock)
Creates a new character-stream writer whose critical sections will synchronize on the given object.
Parameters | |
---|---|
lock |
Object :
Object to synchronize on
|
Writer append (char c)
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)
Parameters | |
---|---|
c |
char :
The 16-bit character to append |
Returns | |
---|---|
Writer |
This writer |
Throws | |
---|---|
IOException |
If an I/O error occurs |
Writer append (CharSequence csq, int start, int end)
Appends a subsequence of the specified character sequence to this writer. Appendable.
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())
Parameters | |
---|---|
csq |
CharSequence :
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 |
int :
The index of the first character in the subsequence |
end |
int :
The index of the character following the last character in the
subsequence |
Returns | |
---|---|
Writer |
This writer |
Throws | |
---|---|
IndexOutOfBoundsException |
If start or end are negative, start is greater than end, or end is greater than csq.length() |
IOException |
If an I/O error occurs |
Writer append (CharSequence csq)
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.
Parameters | |
---|---|
csq |
CharSequence :
The character sequence to append. If csq is
null, then the four characters "null" are
appended to this writer. |
Returns | |
---|---|
Writer |
This writer |
Throws | |
---|---|
IOException |
If an I/O error occurs |
void close ()
Closes the stream, flushing it first. Once the stream has been closed, further write() or flush() invocations will cause an IOException to be thrown. Closing a previously closed stream has no effect.
Throws | |
---|---|
IOException |
If an I/O error occurs |
void flush ()
Flushes the stream. If the stream has saved any characters from the various write() methods in a buffer, write them immediately to their intended destination. Then, if that destination is another character or byte stream, flush it. Thus one flush() invocation will flush all the buffers in a chain of Writers and OutputStreams.
If the intended destination of this stream is an abstraction provided by the underlying operating system, for example a file, then flushing the stream guarantees only that bytes previously written to the stream are passed to the operating system for writing; it does not guarantee that they are actually written to a physical device such as a disk drive.
Throws | |
---|---|
IOException |
If an I/O error occurs |
void write (String str)
Writes a string.
Parameters | |
---|---|
str |
String :
String to be written |
Throws | |
---|---|
IOException |
If an I/O error occurs |
void write (int c)
Writes a single character. The character to be written is contained in the 16 low-order bits of the given integer value; the 16 high-order bits are ignored.
Subclasses that intend to support efficient single-character output should override this method.
Parameters | |
---|---|
c |
int :
int specifying a character to be written |
Throws | |
---|---|
IOException |
If an I/O error occurs |
void write (String str, int off, int len)
Writes a portion of a string.
Parameters | |
---|---|
str |
String :
A String |
off |
int :
Offset from which to start writing characters |
len |
int :
Number of characters to write |
Throws | |
---|---|
IndexOutOfBoundsException |
If off is negative, or len is negative, or off+len is negative or greater than the length of the given string |
IOException |
If an I/O error occurs |
void write (char[] cbuf, int off, int len)
Writes a portion of an array of characters.
Parameters | |
---|---|
cbuf |
char :
Array of characters |
off |
int :
Offset from which to start writing characters |
len |
int :
Number of characters to write |
Throws | |
---|---|
IOException |
If an I/O error occurs |
void write (char[] cbuf)
Writes an array of characters.
Parameters | |
---|---|
cbuf |
char :
Array of characters to be written |
Throws | |
---|---|
IOException |
If an I/O error occurs |