Mercurial > projects > dwt2

annotate org.eclipse.core.jobs/src/org/eclipse/core/runtime/jobs/ILock.d @ 12:bc29606a740c

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Added dwt-addons in original directory structure of eclipse.org
author Frank Benoit <benoit@tionex.de>
date Sat, 14 Mar 2009 18:23:29 +0100
parents
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
12
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
1 /*******************************************************************************
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
2 * Copyright (c) 2003, 2008 IBM Corporation and others.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
3 * All rights reserved. This program and the accompanying materials
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
4 * are made available under the terms of the Eclipse Public License v1.0
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
5 * which accompanies this distribution, and is available at
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
6 * http://www.eclipse.org/legal/epl-v10.html
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
7 *
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
8 * Contributors:
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
9 * IBM - Initial API and implementation
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
10 * Port to the D programming language:
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
11 * Frank Benoit <benoit@tionex.de>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
12 *******************************************************************************/
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
13 module org.eclipse.core.runtime.jobs.ILock;
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
14
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
15 import java.lang.all;
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
16
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
17 /**
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
18 * A lock is used to control access to an exclusive resource.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
19 * <p>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
20 * Locks are reentrant. That is, they can be acquired multiple times by the same thread
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
21 * without releasing. Locks are only released when the number of successful acquires
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
22 * equals the number of successful releases.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
23 * </p><p>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
24 * Locks are capable of detecting and recovering from programming errors that cause
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
25 * circular waiting deadlocks. When a deadlock between two or more <tt>ILock</tt>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
26 * instances is detected, detailed debugging information is printed to the log file. The
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
27 * locks will then automatically recover from the deadlock by employing a release
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
28 * and wait strategy. One thread will lose control of the locks it owns, thus breaking
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
29 * the deadlock and allowing other threads to proceed. Once that thread's locks are
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
30 * all available, it will be given exclusive access to all its locks and allowed to proceed.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
31 * A thread can only lose locks while it is waiting on an <tt>acquire()</tt> call.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
32 *
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
33 * </p><p>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
34 * Successive acquire attempts by different threads are queued and serviced on
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
35 * a first come, first served basis.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
36 * </p><p>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
37 * It is very important that acquired locks eventually get released. Calls to release
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
38 * should be done in a finally block to ensure they execute. For example:
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
39 * <pre>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
40 * try {
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
41 * lock.acquire();
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
42 * // ... do work here ...
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
43 * } finally {
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
44 * lock.release();
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
45 * }
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
46 * </pre>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
47 * Note: although <tt>lock.acquire</tt> should never fail, it is good practice to place
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
48 * it inside the try block anyway. Releasing without acquiring is far less catastrophic
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
49 * than acquiring without releasing.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
50 * </p>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
51 *
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
52 * @see IJobManager#newLock()
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
53 * @since 3.0
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
54 * @noimplement This interface is not intended to be implemented by clients.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
55 */
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
56 public interface ILock {
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
57 /**
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
58 * Attempts to acquire this lock. If the lock is in use and the specified delay is
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
59 * greater than zero, the calling thread will block until one of the following happens:
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
60 * <ul>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
61 * <li>This lock is available</li>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
62 * <li>The thread is interrupted</li>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
63 * <li>The specified delay has elapsed</li>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
64 * </ul>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
65 * <p>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
66 * While a thread is waiting, locks it already owns may be granted to other threads
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
67 * if necessary to break a deadlock. In this situation, the calling thread may be blocked
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
68 * for longer than the specified delay. On returning from this call, the calling thread
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
69 * will once again have exclusive access to any other locks it owned upon entering
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
70 * the acquire method.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
71 *
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
72 * @param delay the number of milliseconds to delay
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
73 * @return <code>true</code> if the lock was successfully acquired, and
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
74 * <code>false</code> otherwise.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
75 * @exception InterruptedException if the thread was interrupted
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
76 */
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
77 public bool acquire(long delay);
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
78
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
79 /**
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
80 * Acquires this lock. If the lock is in use, the calling thread will block until the lock
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
81 * becomes available. If the calling thread owns several locks, it will be blocked
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
82 * until all threads it requires become available, or until the thread is interrupted.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
83 * While a thread is waiting, its locks may be granted to other threads if necessary
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
84 * to break a deadlock. On returning from this call, the calling thread will
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
85 * have exclusive access to this lock, and any other locks it owned upon
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
86 * entering the acquire method.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
87 * <p>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
88 * This implementation ignores attempts to interrupt the thread. If response to
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
89 * interruption is needed, use the method <code>acquire(long)</code>
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
90 */
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
91 public void acquire();
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
92
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
93 /**
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
94 * Returns the number of nested acquires on this lock that have not been released.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
95 * This is the number of times that release() must be called before the lock is
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
96 * freed.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
97 *
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
98 * @return the number of nested acquires that have not been released
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
99 */
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
100 public int getDepth();
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
101
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
102 /**
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
103 * Releases this lock. Locks must only be released by the thread that currently
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
104 * owns the lock.
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
105 */
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
106 public void release();
bc29606a740c Added dwt-addons in original directory structure of eclipse.org
Frank Benoit <benoit@tionex.de>
parents:
diff changeset
107 }