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Java > Open Source Codes > org > springframework > webflow > execution > repository > support > ConversationBackedFlowExecutionLock


1 /*
2  * Copyright 2002-2006 the original author or authors.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.springframework.webflow.execution.repository.support;
17
18 import org.springframework.webflow.conversation.Conversation;
19 import org.springframework.webflow.conversation.ConversationManager;
20 import org.springframework.webflow.execution.repository.FlowExecutionLock;
21
22 /**
23  * A flow execution lock that locks a conversation managed by a
24  * {@link ConversationManager}.
25  * <p>
26  * This implementation ensures multiple threads cannot manipulate the same
27  * conversation at the same time. The locked conversation is the sole gateway to
28  * a flow execution, and a lock on it prevents access to any associated
29  * execution.
30  *
31  * @see ConversationManager
32  * @see Conversation
33  * @see Conversation#lock()
34  * @see Conversation#unlock()
35  *
36  * @author Keith Donald
37  */
38 class ConversationBackedFlowExecutionLock implements FlowExecutionLock {
39
40     /**
41      * The conversation to lock.
42      */
43     private Conversation conversation;
44
45     /**
46      * Creates a new conversation-backed flow execution lock.
47      * @param conversation the conversation to lock
48      */
49     public ConversationBackedFlowExecutionLock(Conversation conversation) {
50         this.conversation = conversation;
51     }
52
53     public void lock() {
54         conversation.lock();
55     }
56
57     public void unlock() {
58         conversation.unlock();
59     }
60 }
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