File	Doc	Category	Size	Date	Package
Writer.java	API Doc	Java SE 6 API	9144	Tue Jun 10 00:25:34 BST 2008	java.io

Writer

• java.lang.Object

Fields Summary
private char[]	writeBuffer Temporary buffer used to hold writes of strings and single characters
private final int	writeBufferSize Size of writeBuffer, must be >= 1
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.

Constructors Summary
protected Writer() Creates a new character-stream writer whose critical sections will synchronize on the writer itself. this.lock = this;
protected Writer(Object lock) Creates a new character-stream writer whose critical sections will synchronize on the given object. param lock Object to synchronize on if (lock == null) { throw new NullPointerException(); } this.lock = lock;

Methods Summary
public java.io.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) param c The 16-bit character to append return This writer throws IOException If an I/O error occurs since 1.5 write(c); return this;
public java.io.Writer	append(java.lang.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. param csq The character sequence to append. If csq is null, then the four characters "null" are appended to this writer. return This writer throws IOException If an I/O error occurs since 1.5 if (csq == null) write("null"); else write(csq.toString()); return this;
public java.io.Writer	append(java.lang.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()) param 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". param start The index of the first character in the subsequence param end The index of the character following the last character in the subsequence return This writer throws IndexOutOfBoundsException If start or end are negative, start is greater than end, or end is greater than csq.length() throws IOException If an I/O error occurs since 1.5 CharSequence cs = (csq == null ? "null" : csq); write(cs.subSequence(start, end).toString()); return this;
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(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. param c int specifying a character to be written throws IOException If an I/O error occurs synchronized (lock) { if (writeBuffer == null){ writeBuffer = new char[writeBufferSize]; } writeBuffer[0] = (char) c; write(writeBuffer, 0, 1); }
public void	write(char[] cbuf) Writes an array of characters. param cbuf Array of characters to be written throws IOException If an I/O error occurs write(cbuf, 0, cbuf.length);
public abstract void	write(char[] cbuf, int off, int len) Writes a portion of an array of characters. param cbuf Array of characters param off Offset from which to start writing characters param len Number of characters to write throws IOException If an I/O error occurs
public void	write(java.lang.String str) Writes a string. param str String to be written throws IOException If an I/O error occurs write(str, 0, str.length());
public void	write(java.lang.String str, int off, int len) Writes a portion of a string. param str A String param off Offset from which to start writing characters param 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 throws IOException If an I/O error occurs synchronized (lock) { char cbuf[]; if (len <= writeBufferSize) { if (writeBuffer == null) { writeBuffer = new char[writeBufferSize]; } cbuf = writeBuffer; } else { // Don't permanently allocate very large buffers. cbuf = new char[len]; } str.getChars(off, (off + len), cbuf, 0); write(cbuf, 0, len); }