/*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to You under the Apache License, Version 2.0

  * (the "License"); you may not use this file except in compliance with

  * 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

  * limitations under the License.

  */

 package org.apache.commons.transaction.locking;

 /**

  * A multi level lock. Depending on the implementation more than one owner may own a certain lock level on the same lock.

  * 

  * @version $Id: MultiLevelLock.java 493628 2007-01-07 01:42:48Z joerg $

  * @see LockManager

  */

 public interface MultiLevelLock {

     /**

      * Tries to acquire a certain lock level on this lock.

      * 

      * @param ownerId a unique id identifying the entity that wants to acquire a certain lock level on this lock

      * @param targetLockLevel the lock level to acquire

      * @param wait <code>true</code> if this method shall block when the desired lock level can not be acquired

      * @param reentrant <code>true</code> if lock levels of the same entity acquired earlier 

      * should not restrict compatibility with the lock level desired now   

      * @param timeoutMSecs if blocking is enabled by the <code>wait</code> parameter this specifies the maximum wait time in milliseconds

      * @return <code>true</code> if the lock actually was acquired 

      * @throws InterruptedException when the thread waiting on this method is interrupted

      */

     public boolean acquire(Object ownerId, int targetLockLevel, boolean wait, boolean reentrant, long timeoutMSecs)

         throws InterruptedException;

     /**

      * Releases any lock levels the specified owner may hold on this lock.

      * 

      * @param ownerId a unique id identifying the entity that wants to release all lock levels

      * @return <code>true</code> if the lock actually was released, <code>false</code> in case

      * there was no lock held by the owner

      */

     public boolean release(Object ownerId);

    /**

     * Retuns the highest lock level the specified owner holds on this lock or <code>0</code> if it holds no locks at all. 

     * 

     * @param ownerId a unique id identifying the entity that wants to know its highest lock level

     * @return the highest lock level

     */

     public int getLockLevel(Object ownerId);

 }