Class Writer

lib/java/io/Writer.java:37–253

The base class for all writers. A writer is a means of writing data to a target in a character-wise manner. Most output streams expect the #flush() method to be called before closing the stream, to ensure all data is actually written out. This abstract class does not provide a fully work

 * @see Reader
 */
public abstract class Writer implements Appendable, Closeable, Flushable {

    static final String TOKEN_NULL = "null"; //$NON-NLS-1$

    /**
     * The object used to synchronize access to the writer.
     */
    protected Object lock;

    /**
     * Constructs a new {@code Writer} with {@code this} as the object used to
     * synchronize critical sections.
     */
    protected Writer() {
        super();
        lock = this;
    }

    /**
     * Constructs a new {@code Writer} with {@code lock} used to synchronize
     * critical sections.
     * 
     * @param lock
     *            the {@code Object} used to synchronize critical sections.
     * @throws NullPointerException
     *             if {@code lock} is {@code null}.
     */
    protected Writer(Object lock) {
        if (lock == null) {
            throw new NullPointerException();
        }
        this.lock = lock;
    }

    /**
     * Closes this writer. Implementations of this method should free any
     * resources associated with the writer.
     * 
     * @throws IOException
     *             if an error occurs while closing this writer.
     */
    public abstract void close() throws IOException;

    /**
     * Flushes this writer. Implementations of this method should ensure that
     * all buffered characters are written to the target.
     * 
     * @throws IOException
     *             if an error occurs while flushing this writer.
     */
    public abstract void flush() throws IOException;

    /**
     * Writes the entire character buffer {@code buf} to the target.
     * 
     * @param buf
     *            the non-null array containing characters to write.
     * @throws IOException