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25 
26 package java.nio.channels;
27 
28 /**
29  * A handler for consuming the result of an asynchronous I/O operation.
30  *
31  * <p> The asynchronous channels defined in this package allow a completion
32  * handler to be specified to consume the result of an asynchronous operation.
33  * The {@link #completed completed} method is invoked when the I/O operation
34  * completes successfully. The {@link #failed failed} method is invoked if the
35  * I/O operations fails. The implementations of these methods should complete
36  * in a timely manner so as to avoid keeping the invoking thread from dispatching
37  * to other completion handlers.
38  *
39  * @param   <V>     The result type of the I/O operation
40  * @param   <A>     The type of the object attached to the I/O operation
41  *
42  * @since 1.7
43  */
44 
45 public interface CompletionHandler<V,A> {
46 
47     /**
48      * Invoked when an operation has completed.
49      *
50      * @param   result
51      *          The result of the I/O operation.
52      * @param   attachment
53      *          The object attached to the I/O operation when it was initiated.
54      */
completed(V result, A attachment)55     void completed(V result, A attachment);
56 
57     /**
58      * Invoked when an operation fails.
59      *
60      * @param   exc
61      *          The exception to indicate why the I/O operation failed
62      * @param   attachment
63      *          The object attached to the I/O operation when it was initiated.
64      */
failed(Throwable exc, A attachment)65     void failed(Throwable exc, A attachment);
66 }
67