Save This Page
Home » openjdk-7 » java » io » [javadoc | source]
java.io
abstract public class: Writer [javadoc | source]
java.lang.Object
   java.io.Writer

All Implemented Interfaces:
    Flushable, Closeable, Appendable

Direct Known Subclasses:
    BodyContent, FilterWriter, FileWriter, CharArrayWriter, StringWriter, NPrintWriter, JspWriter, OutputStreamWriter, PipedWriter, PrintWriter, BufferedWriter

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.
Field 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. 
Constructor:
 protected Writer() 
 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
Method from java.io.Writer Summary:
append,   append,   append,   close,   flush,   write,   write,   write,   write,   write
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.io.Writer Detail:
 public 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.

 public 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) 
 public 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()) 
 abstract public  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.
 abstract public  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.

 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.

 public  void write(char[] cbuf) throws IOException 
    Writes an array of characters.
 public  void write(String str) throws IOException 
    Writes a string.
 abstract public  void write(char[] cbuf,
    int off,
    int len) throws IOException
    Writes a portion of an array of characters.
 public  void write(String str,
    int off,
    int len) throws IOException 
    Writes a portion of a string.