001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.transaction.locking;
018    
019    /**
020     * A multi level lock. Depending on the implementation more than one owner may own a certain lock level on the same lock.
021     * 
022     * @version $Id: MultiLevelLock.java 493628 2007-01-07 01:42:48Z joerg $
023     * @see LockManager
024     */
025    public interface MultiLevelLock {
026    
027        /**
028         * Tries to acquire a certain lock level on this lock.
029         * 
030         * @param ownerId a unique id identifying the entity that wants to acquire a certain lock level on this lock
031         * @param targetLockLevel the lock level to acquire
032         * @param wait <code>true</code> if this method shall block when the desired lock level can not be acquired
033         * @param reentrant <code>true</code> if lock levels of the same entity acquired earlier 
034         * should not restrict compatibility with the lock level desired now   
035         * @param timeoutMSecs if blocking is enabled by the <code>wait</code> parameter this specifies the maximum wait time in milliseconds
036         * @return <code>true</code> if the lock actually was acquired 
037         * @throws InterruptedException when the thread waiting on this method is interrupted
038         */
039        public boolean acquire(Object ownerId, int targetLockLevel, boolean wait, boolean reentrant, long timeoutMSecs)
040            throws InterruptedException;
041    
042        /**
043         * Releases any lock levels the specified owner may hold on this lock.
044         * 
045         * @param ownerId a unique id identifying the entity that wants to release all lock levels
046         * @return <code>true</code> if the lock actually was released, <code>false</code> in case
047         * there was no lock held by the owner
048         */
049        public boolean release(Object ownerId);
050    
051       /**
052        * Retuns the highest lock level the specified owner holds on this lock or <code>0</code> if it holds no locks at all. 
053        * 
054        * @param ownerId a unique id identifying the entity that wants to know its highest lock level
055        * @return the highest lock level
056        */
057        public int getLockLevel(Object ownerId);
058    }