OpenJDK 1.22 · java.io.Writer · APIdia, the JavaDoc alternative

Modifier and Type	Field and Description
protected Object	lock The object used to synchronize operations on this stream.
private static final int	WRITE_BUFFER_SIZE Size of writeBuffer, must be >= 1
private char[]	writeBuffer Temporary buffer used to hold writes of strings and single characters

Access	Constructor and Description
protected	Writer() Creates a new character-stream writer whose critical sections will synchronize on the writer itself.
pack-priv	Writer(Writer writer) For use by BufferedWriter to create a character-stream writer that uses an internal lock when BufferedWriter is not extended and the given writer is trusted, otherwise critical sections will synchronize on the given writer.
protected	Writer(Object Object to synchronize on lock) Creates a new character-stream writer whose critical sections will synchronize on the given object.

Method Summary

Modifier and Type	Method and Description
public Writer	Returns: This writer append(CharSequence The character sequence to append. If `csq` is `null`, then the four characters `"null"` are appended to this writer. csq) Implements java.lang.Appendable.append. Appends the specified character sequence to this writer.
public Writer	Returns: This writer append(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"`. csq, int The index of the first character in the subsequence start, int The index of the character following the last character in the subsequence end) Implements java.lang.Appendable.append. Appends a subsequence of the specified character sequence to this writer.
public Writer	Returns: This writer append(char The 16-bit character to append c) Implements java.lang.Appendable.append. Appends the specified character to this writer.
public abstract void	close() Redeclares java.io.Closeable.close. Closes the stream, flushing it first.
public abstract void	flush() Redeclares java.io.Flushable.flush. Flushes the stream.
private void	implWrite(int c)
private void	implWrite(String str, int off, int len)
public static Writer	Returns: a `Writer` which discards all characters nullWriter() Returns a new `Writer` which discards all characters.
public void	write(int int specifying a character to be written c) Writes a single character.
public void	write(char[] Array of characters to be written cbuf) Writes an array of characters.
public abstract void	write(char[] Array of characters cbuf, int Offset from which to start writing characters off, int Number of characters to write len) Writes a portion of an array of characters.
public void	write(String String to be written str) Writes a string.
public void	write(String A String str, int Offset from which to start writing characters off, int Number of characters to write len) Writes a portion of a string.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

lock	back to summary
protected 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.

WRITE_BUFFER_SIZE	back to summary
private static final int WRITE_BUFFER_SIZE Size of writeBuffer, must be >= 1

writeBuffer	back to summary
private char[] writeBuffer Temporary buffer used to hold writes of strings and single characters

Writer	back to summary
protected Writer() Creates a new character-stream writer whose critical sections will synchronize on the writer itself.

Writer	back to summary
pack-priv Writer(Writer writer) For use by BufferedWriter to create a character-stream writer that uses an internal lock when BufferedWriter is not extended and the given writer is trusted, otherwise critical sections will synchronize on the given writer.

Writer	back to summary
protected 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

Method Detail

append back to summary

append	back to summary
public Writer append(CharSequence csq) throws IOException Implements java.lang.Appendable.append. 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())` 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 Exceptions IOException: If an I/O error occurs Since 1.5

public Writer append(CharSequence csq) throws IOException

Implements java.lang.Appendable.append.

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

Exceptions

IOException:: If an I/O error occurs

Since

1.5

append back to summary

append	back to summary
public Writer append(CharSequence csq, int start, int end) throws IOException Implements java.lang.Appendable.append. 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())` 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 Exceptions IOException: If an I/O error occurs IndexOutOfBoundsException: If `start` or `end` are negative, `start` is greater than `end`, or `end` is greater than `csq.length()` Since 1.5

public Writer append(CharSequence csq, int start, int end) throws IOException

Implements java.lang.Appendable.append.

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

Exceptions

IOException:: If an I/O error occurs
IndexOutOfBoundsException:: If start or end are negative, start is greater than end, or end is greater than csq.length()

Since

1.5

append back to summary

append	back to summary
public Writer append(char c) throws IOException Implements java.lang.Appendable.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 invocation `out.write(c)` out.write(c) Parameters c:char The 16-bit character to append Returns:Writer This writer Exceptions IOException: If an I/O error occurs Since 1.5

public Writer append(char c) throws IOException

Implements java.lang.Appendable.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 invocation

out.write(c)

Parameters

c:char: The 16-bit character to append

Returns:Writer

This writer

Exceptions

IOException:: If an I/O error occurs

Since

1.5

close	back to summary
public abstract void close() throws IOException Redeclares java.io.Closeable.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. Exceptions IOException: If an I/O error occurs

back to summary

public abstract void close() throws IOException

Redeclares java.io.Closeable.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.

Exceptions

IOException:: If an I/O error occurs

flush	back to summary
public abstract void flush() throws IOException Redeclares java.io.Flushable.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. Exceptions IOException: If an I/O error occurs

flush

back to summary

public abstract void flush() throws IOException

Redeclares java.io.Flushable.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.

Exceptions

IOException:: If an I/O error occurs

implWrite	back to summary
private void implWrite(int c) throws IOException

implWrite	back to summary
private void implWrite(String str, int off, int len) throws IOException

nullWriter back to summary

nullWriter	back to summary
public static Writer nullWriter() Returns a new `Writer` which discards all characters. The returned stream is initially open. The stream is closed by calling the `close()` method. Subsequent calls to `close()` have no effect. While the stream is open, the `append(char)`, `append(CharSequence)`, `append(CharSequence, int, int)`, `flush()`, `write(int)`, `write(char[])`, and `write(char[], int, int)` methods do nothing. After the stream has been closed, these methods all throw `IOException`. The `object` used to synchronize operations on the returned `Writer` is not specified. Returns:Writer a `Writer` which discards all characters Since 11

public static Writer nullWriter()

Returns a new Writer which discards all characters. The returned stream is initially open. The stream is closed by calling the close() method. Subsequent calls to close() have no effect.

While the stream is open, the append(char), append(CharSequence), append(CharSequence, int, int), flush(), write(int), write(char[]), and write(char[], int, int) methods do nothing. After the stream has been closed, these methods all throw IOException.

The object used to synchronize operations on the returned Writer is not specified.

Returns:Writer: a Writer which discards all characters
Since: 11

write	back to summary
public void write(int c) throws IOException 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 Exceptions IOException: If an I/O error occurs

write

back to summary

public void write(int c) throws IOException

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

Exceptions

IOException:: If an I/O error occurs

write	back to summary
public void write(char[] cbuf) throws IOException Writes an array of characters. Parameters cbuf:char[] Array of characters to be written Exceptions IOException: If an I/O error occurs

write

back to summary

public void write(char[] cbuf) throws IOException

Writes an array of characters.

Parameters

cbuf:char[]: Array of characters to be written

Exceptions

IOException:: If an I/O error occurs

write back to summary

write	back to summary
public abstract void write(char[] cbuf, int off, int len) throws IOException 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 Exceptions IOException: If an I/O error occurs IndexOutOfBoundsException: Implementations should throw this exception if `off` is negative, or `len` is negative, or `off + len` is negative or greater than the length of the given array

public abstract void write(char[] cbuf, int off, int len) throws IOException

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

Exceptions

IOException:: If an I/O error occurs
IndexOutOfBoundsException:: Implementations should throw this exception if off is negative, or len is negative, or off + len is negative or greater than the length of the given array

write	back to summary
public void write(String str) throws IOException Writes a string. Parameters str:String String to be written Exceptions IOException: If an I/O error occurs

write

back to summary

public void write(String str) throws IOException

Writes a string.

Parameters

str:String: String to be written

Exceptions

IOException:: If an I/O error occurs

write back to summary

write	back to summary
public void write(String str, int off, int len) throws IOException Writes a portion of a string. Implementation Specification The implementation in this class throws an `IndexOutOfBoundsException` for the indicated conditions; overriding methods may choose to do otherwise. Parameters str:String A String off:int Offset from which to start writing characters len:int Number of characters to write Exceptions IOException: If an I/O error occurs IndexOutOfBoundsException: Implementations should throw this exception if `off` is negative, or `len` is negative, or `off + len` is negative or greater than the length of the given string

public void write(String str, int off, int len) throws IOException

Writes a portion of a string.

Implementation Specification

The implementation in this class throws an IndexOutOfBoundsException for the indicated conditions; overriding methods may choose to do otherwise.

Parameters

str:String: A String
off:int: Offset from which to start writing characters
len:int: Number of characters to write

Exceptions

IOException:: If an I/O error occurs
IndexOutOfBoundsException:: Implementations should throw this exception if off is negative, or len is negative, or off + len is negative or greater than the length of the given string

public abstract Class Writer

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