public abstract class Writer extends Object implements Appendable, Closeable, Flushable
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.
Writer, BufferedWriter, CharArrayWriter, FilterWriter, OutputStreamWriter, FileWriter, PipedWriter, PrintWriter, StringWriter, Reader
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 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.
lock - Object to synchronize onpublic 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.
c - int specifying a character to be writtenIOException - If an I/O error occurspublic void write(char[] cbuf)
throws IOException Writes an array of characters.
cbuf - Array of characters to be writtenIOException - If an I/O error occurspublic abstract void write(char[] cbuf,
int off,
int len)
throws IOException Writes a portion of an array of characters.
cbuf - Array of charactersoff - Offset from which to start writing characterslen - Number of characters to writeIOException - If an I/O error occurspublic void write(String str)
throws IOException Writes a string.
str - String to be writtenIOException - If an I/O error occurspublic void write(String str,
int off,
int len)
throws IOException Writes a portion of a string.
str - A Stringoff - Offset from which to start writing characterslen - Number of characters to writeIndexOutOfBoundsException - If off is negative, or len is negative, or off+len is negative or greater than the length of the given stringIOException - If an I/O error occurspublic Writer append(CharSequence csq)
throws IOException 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.
append in interface Appendable
csq - The character sequence to append. If csq is null, then the four characters "null" are appended to this writer.IOException - If an I/O error occurspublic Writer append(CharSequence csq,
int start,
int end)
throws IOException 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())
append in interface Appendable
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 subsequenceend - The index of the character following the last character in the subsequenceIndexOutOfBoundsException - If start or end are negative, start is greater than end, or end is greater than csq.length()
IOException - If an I/O error occurspublic Writer append(char c)
throws IOException 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)
append in interface Appendable
c - The 16-bit character to appendIOException - If an I/O error occurspublic abstract void flush()
throws IOException 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.
flush in interface Flushable
IOException - If an I/O error occurspublic abstract void close()
throws IOException 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.
close in interface Closeable
close in interface AutoCloseable
IOException - If an I/O error occurs
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