Writer - JRE Emulation | JRE Emulation
public abstract class

Writer

extends Object
implements Appendable Closeable Flushable
java.lang.Object
   ↳ java.io.Writer
Known Direct Subclasses
Known Indirect Subclasses

Class Overview

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.

Summary

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
[Expand]
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

Fields

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.

Protected Constructors

protected Writer ()

Creates a new character-stream writer whose critical sections will synchronize on the writer itself.

protected Writer (Object lock)

Creates a new character-stream writer whose critical sections will synchronize on the given object.

Parameters
lock Object to synchronize on

Public Methods

public 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 The 16-bit character to append
Returns
  • This writer
Throws
IOException If an I/O error occurs

public 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 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 The index of the first character in the subsequence
end The index of the character following the last character in the subsequence
Returns
  • 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

public 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 The character sequence to append. If csq is null, then the four characters "null" are appended to this writer.
Returns
  • This writer
Throws
IOException If an I/O error occurs

public abstract 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

public abstract 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

public void write (String str)

Writes a string.

Parameters
str String to be written
Throws
IOException If an I/O error occurs

public 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 specifying a character to be written
Throws
IOException If an I/O error occurs

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

Writes a portion of a string.

Parameters
str A String
off Offset from which to start writing characters
len 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

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

Writes a portion of an array of characters.

Parameters
cbuf Array of characters
off Offset from which to start writing characters
len Number of characters to write
Throws
IOException If an I/O error occurs

public void write (char[] cbuf)

Writes an array of characters.

Parameters
cbuf Array of characters to be written
Throws
IOException If an I/O error occurs