01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * http://www.apache.org/licenses/LICENSE-2.0
10: *
11: * Unless required by applicable law or agreed to in writing, software
12: * distributed under the License is distributed on an "AS IS" BASIS,
13: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14: * See the License for the specific language governing permissions and
15: * limitations under the License.
16: */
17:
18: package org.apache.tomcat.jni;
19:
20: /** Global
21: *
22: * @author Mladen Turk
23: * @version $Revision: 467222 $, $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
24: */
25:
26: public class Global {
27:
28: /**
29: * Create and initialize a mutex that can be used to synchronize both
30: * processes and threads. Note: There is considerable overhead in using
31: * this API if only cross-process or cross-thread mutual exclusion is
32: * required. See apr_proc_mutex.h and apr_thread_mutex.h for more
33: * specialized lock routines.
34: * <br /><b>Warning :</b> Check APR_HAS_foo_SERIALIZE defines to see if the platform supports
35: * APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable.
36: * @param fname A file name to use if the lock mechanism requires one. This
37: * argument should always be provided. The lock code itself will
38: * determine if it should be used.
39: * @param mech The mechanism to use for the interprocess lock, if any; one of
40: * <PRE>
41: * APR_LOCK_FCNTL
42: * APR_LOCK_FLOCK
43: * APR_LOCK_SYSVSEM
44: * APR_LOCK_POSIXSEM
45: * APR_LOCK_PROC_PTHREAD
46: * APR_LOCK_DEFAULT pick the default mechanism for the platform
47: * </PRE>
48: * @param pool the pool from which to allocate the mutex.
49: * @return Newly created mutex.
50: */
51: public static native long create(String fname, int mech, long pool)
52: throws Error;
53:
54: /**
55: * Re-open a mutex in a child process.
56: * @param fname A file name to use if the mutex mechanism requires one. This
57: * argument should always be provided. The mutex code itself will
58: * determine if it should be used. This filename should be the
59: * same one that was passed to apr_proc_mutex_create().
60: * @param pool The pool to operate on.
61: * This function must be called to maintain portability, even
62: * if the underlying lock mechanism does not require it.
63: * @return Newly opened mutex.
64: */
65: public static native long childInit(String fname, long pool)
66: throws Error;
67:
68: /**
69: * Acquire the lock for the given mutex. If the mutex is already locked,
70: * the current thread will be put to sleep until the lock becomes available.
71: * @param mutex the mutex on which to acquire the lock.
72: */
73: public static native int lock(long mutex);
74:
75: /**
76: * Attempt to acquire the lock for the given mutex. If the mutex has already
77: * been acquired, the call returns immediately with APR_EBUSY. Note: it
78: * is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine
79: * if the return value was APR_EBUSY, for portability reasons.
80: * @param mutex the mutex on which to attempt the lock acquiring.
81: */
82: public static native int trylock(long mutex);
83:
84: /**
85: * Release the lock for the given mutex.
86: * @param mutex the mutex from which to release the lock.
87: */
88: public static native int unlock(long mutex);
89:
90: /**
91: * Destroy the mutex and free the memory associated with the lock.
92: * @param mutex the mutex to destroy.
93: */
94: public static native int destroy(long mutex);
95:
96: }
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