org.apache.commons.transaction.locking.LockManager.java Source code

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Here is the source code for org.apache.commons.transaction.locking.LockManager.java

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/*
 * 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 manager for multi level locks on resources. Encapsulates creation, removal, and retrieval of locks.
 * Each resource can have at most a single lock. However, it may be possible for more than one
 * accessing entity to have influence on this lock via different lock levels that may be 
 * provided by the according implementation of {@link MultiLevelLock}. 
 * 
 * @version $Id: LockManager.java 493628 2007-01-07 01:42:48Z joerg $
 * @see MultiLevelLock
 */
public interface LockManager {

    /**
     * Either gets an existing lock on the specified resource or creates one if none exists. 
     * This methods guarantees to do this atomically. 
     * 
     * @param resourceId the resource to get or create the lock on
     * @return the lock for the specified resource
     */
    public MultiLevelLock atomicGetOrCreateLock(Object resourceId);

    /**
     * Gets an existing lock on the specified resource. If none exists it returns <code>null</code>. 
     * 
     * @param resourceId the resource to get the lock for
     * @return the lock on the specified resource
     */
    public MultiLevelLock getLock(Object resourceId);

    /**
     * Removes the specified lock from the associated resource. 
     * 
     * @param lock the lock to be removed
     */
    public void removeLock(MultiLevelLock lock);
}