1 /*

     2  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.

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

     4  *

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

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

     7  * published by the Free Software Foundation.  Oracle designates this

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

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

    10  *

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

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

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

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

    15  * accompanied this code).

    16  *

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

    18  * 2 along with this work; if not, write to the Free Software Foundation,

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

    20  *

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

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package sun.nio.ch;

    27 

    28 import java.util.concurrent.Future;

    29 import java.util.concurrent.TimeUnit;

    30 import java.util.concurrent.ExecutionException;

    31 import java.io.IOException;

    32 

    33 /**

    34  * A Future representing the result of an I/O operation that has already

    35  * completed.

    36  */

    37 

    38 final class CompletedFuture<V> implements Future<V> {

    39     private final V result;

    40     private final Throwable exc;

    41 

    42     private CompletedFuture(V result, Throwable exc) {

    43         this.result = result;

    44         this.exc = exc;

    45     }

    46 

    47     static <V> CompletedFuture<V> withResult(V result) {

    48         return new CompletedFuture<V>(result, null);

    49     }

    50 

    51     static <V> CompletedFuture<V> withFailure(Throwable exc) {

    52         // exception must be IOException or SecurityException

    53         if (!(exc instanceof IOException) && !(exc instanceof SecurityException))

    54             exc = new IOException(exc);

    55         return new CompletedFuture<V>(null, exc);

    56     }

    57 

    58     static <V> CompletedFuture<V> withResult(V result, Throwable exc) {

    59         if (exc == null) {

    60             return withResult(result);

    61         } else {

    62             return withFailure(exc);

    63         }

    64     }

    65 

    66     @Override

    67     public V get() throws ExecutionException {

    68         if (exc != null)

    69             throw new ExecutionException(exc);

    70         return result;

    71     }

    72 

    73     @Override

    74     public V get(long timeout, TimeUnit unit) throws ExecutionException {

    75         if (unit == null)

    76             throw new NullPointerException();

    77         if (exc != null)

    78             throw new ExecutionException(exc);

    79         return result;

    80     }

    81 

    82     @Override

    83     public boolean isCancelled() {

    84         return false;

    85     }

    86 

    87     @Override

    88     public boolean isDone() {

    89         return true;

    90     }

    91 

    92     @Override

    93     public boolean cancel(boolean mayInterruptIfRunning) {

    94         return false;

    95     }

    96 }