/*

 * Copyright (c) 2007, 2009, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package java.nio.channels;

/**

 * A handler for consuming the result of an asynchronous I/O operation.

 *

 * <p> The asynchronous channels defined in this package allow a completion

 * handler to be specified to consume the result of an asynchronous operation.

 * The {@link #completed completed} method is invoked when the I/O operation

 * completes successfully. The {@link #failed failed} method is invoked if the

 * I/O operations fails. The implementations of these methods should complete

 * in a timely manner so as to avoid keeping the invoking thread from dispatching

 * to other completion handlers.

 *

 * @param   <V>     The result type of the I/O operation

 * @param   <A>     The type of the object attached to the I/O operation

 *

 * @since 1.7

 */

public interface CompletionHandler<V,A> {

    /**

     * Invoked when an operation has completed.

     *

     * @param   result

     *          The result of the I/O operation.

     * @param   attachment

     *          The object attached to the I/O operation when it was initiated.

     */

    void completed(V result, A attachment);

    /**

     * Invoked when an operation fails.

     *

     * @param   exc

     *          The exception to indicate why the I/O operation failed

     * @param   attachment

     *          The object attached to the I/O operation when it was initiated.

     */

    void failed(Throwable exc, A attachment);

}