https://tomcat.apache.org/: Interface code to the native connector 
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 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
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package org.apache.tomcat.jni;


Global

Author:Mladen Turk
/** Global
 *
 * @author Mladen Turk
 */
public class Global {

    
Create and initialize a mutex that can be used to synchronize both
processes and threads. Note: There is considerable overhead in using
this API if only cross-process or cross-thread mutual exclusion is
required. See apr_proc_mutex.h and apr_thread_mutex.h for more
specialized lock routines.

Warning : Check APR_HAS_foo_SERIALIZE defines to see if the platform supports
         APR_LOCK_foo.  Only APR_LOCK_DEFAULT is portable.

Params:
  • fname – A file name to use if the lock mechanism requires one.  This
       argument should always be provided.  The lock code itself will
       determine if it should be used.
  • mech – The mechanism to use for the interprocess lock, if any; one of

               APR_LOCK_FCNTL
           APR_LOCK_FLOCK
           APR_LOCK_SYSVSEM
           APR_LOCK_POSIXSEM
           APR_LOCK_PROC_PTHREAD
           APR_LOCK_DEFAULT     pick the default mechanism for the platform

  • pool – the pool from which to allocate the mutex.
Throws:
  • Error – If an error occurred
Returns:Newly created mutex.
/**
     * Create and initialize a mutex that can be used to synchronize both
     * processes and threads. Note: There is considerable overhead in using
     * this API if only cross-process or cross-thread mutual exclusion is
     * required. See apr_proc_mutex.h and apr_thread_mutex.h for more
     * specialized lock routines.
     * <br><b>Warning :</b> Check APR_HAS_foo_SERIALIZE defines to see if the platform supports
     *          APR_LOCK_foo.  Only APR_LOCK_DEFAULT is portable.
     * @param fname A file name to use if the lock mechanism requires one.  This
     *        argument should always be provided.  The lock code itself will
     *        determine if it should be used.
     * @param mech The mechanism to use for the interprocess lock, if any; one of
     * <PRE>
     *            APR_LOCK_FCNTL
     *            APR_LOCK_FLOCK
     *            APR_LOCK_SYSVSEM
     *            APR_LOCK_POSIXSEM
     *            APR_LOCK_PROC_PTHREAD
     *            APR_LOCK_DEFAULT     pick the default mechanism for the platform
     * </PRE>
     * @param pool the pool from which to allocate the mutex.
     * @return Newly created mutex.
     * @throws Error If an error occurred
     */
    public static native long create(String fname, int mech, long pool)
        throws Error;

    
Re-open a mutex in a child process.

Params:
  • fname – A file name to use if the mutex mechanism requires one.  This
             argument should always be provided.  The mutex code itself will
             determine if it should be used.  This filename should be the
             same one that was passed to apr_proc_mutex_create().
  • pool – The pool to operate on.
This function must be called to maintain portability, even
        if the underlying lock mechanism does not require it.
Throws:
  • Error – If an error occurred
Returns:Newly opened mutex.
/**
     * Re-open a mutex in a child process.
     * @param fname A file name to use if the mutex mechanism requires one.  This
     *              argument should always be provided.  The mutex code itself will
     *              determine if it should be used.  This filename should be the
     *              same one that was passed to apr_proc_mutex_create().
     * @param pool The pool to operate on.
     * This function must be called to maintain portability, even
     *         if the underlying lock mechanism does not require it.
     * @return Newly opened mutex.
     * @throws Error If an error occurred
     */
    public static native long childInit(String fname, long pool)
        throws Error;

    
Acquire the lock for the given mutex. If the mutex is already locked,
the current thread will be put to sleep until the lock becomes available.

Params:
  • mutex – the mutex on which to acquire the lock.
Returns:the operation status
/**
     * Acquire the lock for the given mutex. If the mutex is already locked,
     * the current thread will be put to sleep until the lock becomes available.
     * @param mutex the mutex on which to acquire the lock.
     * @return the operation status
     */
    public static native int lock(long mutex);

    
Attempt to acquire the lock for the given mutex. If the mutex has already
been acquired, the call returns immediately with APR_EBUSY. Note: it
is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine
if the return value was APR_EBUSY, for portability reasons.

Params:
  • mutex – the mutex on which to attempt the lock acquiring.
Returns:the operation status
/**
     * Attempt to acquire the lock for the given mutex. If the mutex has already
     * been acquired, the call returns immediately with APR_EBUSY. Note: it
     * is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine
     * if the return value was APR_EBUSY, for portability reasons.
     * @param mutex the mutex on which to attempt the lock acquiring.
     * @return the operation status
     */
    public static native int trylock(long mutex);

    
Release the lock for the given mutex.

Params:
  • mutex – the mutex from which to release the lock.
Returns:the operation status
/**
     * Release the lock for the given mutex.
     * @param mutex the mutex from which to release the lock.
     * @return the operation status
     */
    public static native int unlock(long mutex);

    
Destroy the mutex and free the memory associated with the lock.

Params:
  • mutex – the mutex to destroy.
Returns:the operation status
/**
     * Destroy the mutex and free the memory associated with the lock.
     * @param mutex the mutex to destroy.
     * @return the operation status
     */
    public static native int destroy(long mutex);

}