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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 java.util.concurrent.ConcurrentHashMap;
27  import java.util.concurrent.ConcurrentMap;
28  import net.jcip.annotations.ThreadSafe;
29  
30  /**
31   * The repository-source level cache of workspace names to {@link WorkspaceCache workspace caches}.
32   * <p>
33   * This object gets created for each repository whenever the {@link PathCachePolicy cache policy} is set. When the cache policy is
34   * modified, the old {@code PathRepositoryCache} is {@link #close() closed} after the new path repository cache is created.
35   * </p>
36   */
37  @ThreadSafe
38  public class PathRepositoryCache {
39  
40      private final PathCachePolicy policy;
41      private final ConcurrentMap<String, WorkspaceCache> cachesByName = new ConcurrentHashMap<String, WorkspaceCache>();
42  
43      public PathRepositoryCache( PathCachePolicy policy ) {
44          this.policy = policy;
45      }
46  
47      public void close() {
48          for (WorkspaceCache cache : cachesByName.values()) {
49              cache.close();
50          }
51      }
52  
53      /**
54       * Gets the cache for the named workspace, creating a cache if necessary. Subsequent calls to this method with the same
55       * workspace name must return the exact same cache instance.
56       * 
57       * @param workspaceName the name of the workspace for which the cache should be returned.
58       * @return the cache instance associated with the workspace; never null
59       * @throws IllegalStateException if no cache exists for this workspace and an instance of the
60       *         {@link PathCachePolicy#getCacheClass() cache class from the policy} cannot be created.
61       */
62      public WorkspaceCache getCache( String workspaceName ) {
63          WorkspaceCache cache = cachesByName.get(workspaceName);
64          if (cache != null) return cache;
65  
66          cache = newCache(workspaceName);
67          cachesByName.putIfAbsent(workspaceName, cache);
68  
69          return cachesByName.get(workspaceName);
70      }
71  
72      private final WorkspaceCache newCache( String workspaceName ) {
73          WorkspaceCache cache = null;
74  
75          try {
76              cache = policy.getCacheClass().newInstance();
77              cache.initialize(policy, workspaceName);
78          } catch (IllegalAccessException iae) {
79              throw new IllegalStateException(iae);
80          } catch (InstantiationException ie) {
81              throw new IllegalStateException(ie);
82          }
83          return cache;
84      }
85  
86  }