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: package org.apache.commons.transaction.locking;
18:
19: /**
20: * A manager for multi level locks on resources. Encapsulates creation, removal, and retrieval of locks.
21: * Each resource can have at most a single lock. However, it may be possible for more than one
22: * accessing entity to have influence on this lock via different lock levels that may be
23: * provided by the according implementation of {@link MultiLevelLock}.
24: *
25: * @version $Id: LockManager.java 493628 2007-01-07 01:42:48Z joerg $
26: * @see MultiLevelLock
27: */
28: public interface LockManager {
29:
30: /**
31: * Either gets an existing lock on the specified resource or creates one if none exists.
32: * This methods guarantees to do this atomically.
33: *
34: * @param resourceId the resource to get or create the lock on
35: * @return the lock for the specified resource
36: */
37: public MultiLevelLock atomicGetOrCreateLock(Object resourceId);
38:
39: /**
40: * Gets an existing lock on the specified resource. If none exists it returns <code>null</code>.
41: *
42: * @param resourceId the resource to get the lock for
43: * @return the lock on the specified resource
44: */
45: public MultiLevelLock getLock(Object resourceId);
46:
47: /**
48: * Removes the specified lock from the associated resource.
49: *
50: * @param lock the lock to be removed
51: */
52: public void removeLock(MultiLevelLock lock);
53: }
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