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1   /*
2    * ModeShape (http://www.modeshape.org)
3    * See the COPYRIGHT.txt file distributed with this work for information
4    * regarding copyright ownership.  Some portions may be licensed
5    * to Red Hat, Inc. under one or more contributor license agreements.
6    * See the AUTHORS.txt file in the distribution for a full listing of 
7    * individual contributors. 
8    *
9    * ModeShape is free software. Unless otherwise indicated, all code in ModeShape
10   * is licensed to you under the terms of the GNU Lesser General Public License as
11   * published by the Free Software Foundation; either version 2.1 of
12   * the License, or (at your option) any later version.
13   *
14   * ModeShape is distributed in the hope that it will be useful,
15   * but WITHOUT ANY WARRANTY; without even the implied warranty of
16   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17   * Lesser General Public License for more details.
18   *
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this software; if not, write to the Free
21   * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22   * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
23   */
24  package org.modeshape.graph.connector.path.cache;
25  
26  import net.jcip.annotations.ThreadSafe;
27  import org.modeshape.graph.connector.path.PathNode;
28  import org.modeshape.graph.property.Path;
29  
30  /**
31   * The basic contract for a workspace-level cache of paths to the nodes stored at that path.
32   * <p>
33   * Implementations must provide a no-argument constructor in order to be instantiated by {@link PathRepositoryCache}. After
34   * instantiation, the {@link #initialize(PathCachePolicy, String)} method will be called to inject the cache policy into the
35   * implementation.
36   * </p>
37   * <p>
38   * Implementations must be thread-safe.
39   * </p>
40   */
41  @ThreadSafe
42  public interface WorkspaceCache {
43  
44      /**
45       * Injects the cache policy into the cache
46       * 
47       * @param policy the active cache policy for the repository source with which this cache is associated
48       * @param workspaceName the name of the workspace that this cache is managing
49       * @throws IllegalStateException if this method is called on a cache that has already been initialized.
50       */
51      public void initialize( PathCachePolicy policy,
52                              String workspaceName );
53  
54      /**
55       * Clears all statistics for this cache
56       */
57      public void clearStatistics();
58  
59      /**
60       * @return the statistics since the most recent of the cache initialization or the last call to {@link #clearStatistics()};
61       *         never null
62       */
63      public CacheStatistics getStatistics();
64  
65      /**
66       * Retrieves the cached node with the given path, it it exists and is valid
67       * 
68       * @param path the path for the node to be retrieved
69       * @return the cached node with the given path; may be null if no node with that path is cached or a node with that path is
70       *         cached but is deemed invalid for implementation-specific reasons
71       */
72      public PathNode get( Path path );
73  
74      /**
75       * Attempts to cache the given node. Implementations must call {@link PathCachePolicy#shouldCache(PathNode)} on the policy
76       * from the {@link #initialize(PathCachePolicy, String)} method to determine if the node should be cached.
77       * 
78       * @param node the node that is to be cached; may not be null
79       */
80      public void set( PathNode node );
81  
82      /**
83       * Invalidates all nodes in the cache that have the given path or have a path that is an ancestor of the given path
84       * 
85       * @param path the root of the branch of nodes that are to be invalidated; may not be null
86       */
87      public void invalidate( Path path );
88  
89      /**
90       * Indicates that the cache is no longer in use and should relinquish any resources.
91       */
92      public void close();
93  }