JDK-8067661: transferTo proposal for Appendable

[Patrick Reinhart]

Hi There,

Based on the *transferTo* Method on the InputStream I would propose to
introduce a
default method on the Readable interface. In that way the method can be
used for
all existing implementations of Readable and still be implemented in a
special
way by a individual implementer.


   /**

    * Reads all characters from this readable and writes the characters to
    * the given appendable in the order that they are read. On return, this
    * readable will be at end its data.
    * <p>
    * This method may block indefinitely reading from the readable, or
    * writing to the appendable. The behavior for the case where the
readable
    * and/or appendable is <i>asynchronously closed</i>, or the thread
    * interrupted during the transfer, is highly readable and appendable
    * specific, and therefore not specified.
    * <p>
    * If an I/O error occurs reading from the readable or writing to the
    * appendable, then it may do so after some characters have been read or
    * written. Consequently the readable may not be at end of its data and
    * one, or both participants may be in an inconsistent state. That in
mind
    * all additional measures required by one or both participants in
order to
    * eventually free their internal resources have to be taken by the
caller
    * of this method.
    *
    * @param  out the appendable, non-null
    * @return the number of characters transferred
    * @throws IOException if an I/O error occurs when reading or writing
    * @throws NullPointerException if {@code out} is {@code null}
    *
    * @since 18.3
    */
   default long transferTo(Appendable out) throws IOException {
   ....
   }


Cheers Patrick