01 /*
02 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
03 *
04 * This code is free software; you can redistribute it and/or modify it
05 * under the terms of the GNU General Public License version 2 only, as
06 * published by the Free Software Foundation. Sun designates this
07 * particular file as subject to the "Classpath" exception as provided
08 * by Sun in the LICENSE file that accompanied this code.
09 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
22 * have any questions.
23 */
24
25 /*
26 * This file is available under and governed by the GNU General Public
27 * License version 2 only, as published by the Free Software Foundation.
28 * However, the following notice accompanied the original version of this
29 * file:
30 *
31 * Written by Doug Lea with assistance from members of JCP JSR-166
32 * Expert Group and released to the public domain, as explained at
33 * http://creativecommons.org/licenses/publicdomain
34 */
35
36 package java.util.concurrent;
37
38 /**
39 * A task that returns a result and may throw an exception.
40 * Implementors define a single method with no arguments called
41 * <tt>call</tt>.
42 *
43 * <p>The <tt>Callable</tt> interface is similar to {@link
44 * java.lang.Runnable}, in that both are designed for classes whose
45 * instances are potentially executed by another thread. A
46 * <tt>Runnable</tt>, however, does not return a result and cannot
47 * throw a checked exception.
48 *
49 * <p> The {@link Executors} class contains utility methods to
50 * convert from other common forms to <tt>Callable</tt> classes.
51 *
52 * @see Executor
53 * @since 1.5
54 * @author Doug Lea
55 * @param <V> the result type of method <tt>call</tt>
56 */
57 public interface Callable<V> {
58 /**
59 * Computes a result, or throws an exception if unable to do so.
60 *
61 * @return computed result
62 * @throws Exception if unable to compute a result
63 */
64 V call() throws Exception;
65 }
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