Class Writer
- All Implemented Interfaces:
Closeable
,Flushable
,Appendable
,AutoCloseable
- Direct Known Subclasses:
BufferedWriter
,CharArrayWriter
,FilterWriter
,OutputStreamWriter
,PipedWriter
,PrintWriter
,StringWriter
- Since:
- 1.1
- See Also:
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Field Summary
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionappend
(char c) Appends the specified character to this writer.append
(CharSequence csq) Appends the specified character sequence to this writer.append
(CharSequence csq, int start, int end) Appends a subsequence of the specified character sequence to this writer.abstract void
close()
Closes the stream, flushing it first.abstract void
flush()
Flushes the stream.static Writer
Returns a newWriter
which discards all characters.void
write
(char[] cbuf) Writes an array of characters.abstract void
write
(char[] cbuf, int off, int len) Writes a portion of an array of characters.void
write
(int c) Writes a single character.void
Writes a string.void
Writes a portion of a string.
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Field Details
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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 thanthis
or a synchronized method.
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Constructor Details
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Writer
protected Writer()Creates a new character-stream writer whose critical sections will synchronize on the writer itself. -
Writer
Creates a new character-stream writer whose critical sections will synchronize on the given object.- Parameters:
lock
- Object to synchronize on
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Method Details
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nullWriter
Returns a newWriter
which discards all characters. The returned stream is initially open. The stream is closed by calling theclose()
method. Subsequent calls toclose()
have no effect.While the stream is open, the
append(char)
,append(CharSequence)
,append(CharSequence, int, int)
,flush()
,write(int)
,write(char[])
, andwrite(char[], int, int)
methods do nothing. After the stream has been closed, these methods all throwIOException
.The
object
used to synchronize operations on the returnedWriter
is not specified.- Returns:
- a
Writer
which discards all characters - Since:
- 11
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write
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 specifying a character to be written- Throws:
IOException
- If an I/O error occurs
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write
Writes an array of characters.- Parameters:
cbuf
- Array of characters to be written- Throws:
IOException
- If an I/O error occurs
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write
Writes a portion of an array of characters.- Parameters:
cbuf
- Array of charactersoff
- Offset from which to start writing characterslen
- Number of characters to write- Throws:
IndexOutOfBoundsException
- Implementations should throw this exception ifoff
is negative, orlen
is negative, oroff + len
is negative or greater than the length of the given arrayIOException
- If an I/O error occurs
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write
Writes a string.- Parameters:
str
- String to be written- Throws:
IOException
- If an I/O error occurs
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write
Writes a portion of a string.- Implementation Requirements:
- The implementation in this class throws an
IndexOutOfBoundsException
for the indicated conditions; overriding methods may choose to do otherwise. - Parameters:
str
- A Stringoff
- Offset from which to start writing characterslen
- Number of characters to write- Throws:
IndexOutOfBoundsException
- Implementations should throw this exception ifoff
is negative, orlen
is negative, oroff + len
is negative or greater than the length of the given stringIOException
- If an I/O error occurs
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append
Appends the specified character sequence to this writer.An invocation of this method of the form
out.append(csq)
whencsq
is notnull
, behaves in exactly the same way as the invocationout.write(csq.toString())
Depending on the specification of
toString
for the character sequencecsq
, the entire sequence may not be appended. For instance, invoking thetoString
method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.- Specified by:
append
in interfaceAppendable
- Parameters:
csq
- The character sequence to append. Ifcsq
isnull
, then the four characters"null"
are appended to this writer.- Returns:
- This writer
- Throws:
IOException
- If an I/O error occurs- Since:
- 1.5
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append
Appends a subsequence of the specified character sequence to this writer.An invocation of this method of the form
out.append(csq, start, end)
whencsq
is notnull
behaves in exactly the same way as the invocationout.write(csq.subSequence(start, end).toString())
- Specified by:
append
in interfaceAppendable
- Parameters:
csq
- The character sequence from which a subsequence will be appended. Ifcsq
isnull
, then characters will be appended as ifcsq
contained the four characters"null"
.start
- The index of the first character in the subsequenceend
- The index of the character following the last character in the subsequence- Returns:
- This writer
- Throws:
IndexOutOfBoundsException
- Ifstart
orend
are negative,start
is greater thanend
, orend
is greater thancsq.length()
IOException
- If an I/O error occurs- Since:
- 1.5
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append
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 invocationout.write(c)
- Specified by:
append
in interfaceAppendable
- Parameters:
c
- The 16-bit character to append- Returns:
- This writer
- Throws:
IOException
- If an I/O error occurs- Since:
- 1.5
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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.
- Specified by:
flush
in interfaceFlushable
- Throws:
IOException
- If an I/O error occurs
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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.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Throws:
IOException
- If an I/O error occurs
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