VersionConsistencyCache


1   /*
2    * The contents of this file are subject to the terms 
3    * of the Common Development and Distribution License 
4    * (the License).  You may not use this file except in
5    * compliance with the License.
6    * 
7    * You can obtain a copy of the license at 
8    * https://glassfish.dev.java.net/public/CDDLv1.0.html or
9    * glassfish/bootstrap/legal/CDDLv1.0.txt.
10   * See the License for the specific language governing 
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12   * 
13   * When distributing Covered Code, include this CDDL 
14   * Header Notice in each file and include the License file 
15   * at glassfish/bootstrap/legal/CDDLv1.0.txt.  
16   * If applicable, add the following below the CDDL Header, 
17   * with the fields enclosed by brackets [] replaced by
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20   * 
21   * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
22   */
23  
24  package com.sun.jdo.spi.persistence.support.sqlstore;
25  
26  /**
27   * A cache of "version consistent" StateManager instances.  These instances
28   * are used so that we can avoid loading state from the database.
29   *
30   * @author Dave Bristor
31   */
32  public interface VersionConsistencyCache {
33      /**
34       * Puts the given StateManager into a map that is keyed by the given OID.
35       * We anticipate that implementations will want to use a two-level map,
36       * and so the pc's class can be used as a key into a map to access a
37       * second map, which would be that keyed by OID.
38       * @param pcType class of instance, used as key in outer map.
39       * @param oid Object id, used as key in inner map.
40       * @param sm StateManager bound to <code>oid</code> in inner map.
41       */
42      public StateManager put(Class   pcType, Object   oid, StateManager sm);
43  
44      /**
45       * Returns an SM, if found, else null.
46       * @param pcType class of instance, used as key in outer map.
47       * @param oid Object id, used as key in inner map.
48       */
49      public StateManager get(Class   pcType, Object   oid);
50  
51      /**
52       * Removes entry based on pc and oid.  If map is empty after remove,
53       * removes it from its containint map.
54       * @param pcType class of instance, used as key in outer map.
55       * @param oid Object id, used as key in inner map.
56       */
57      public StateManager remove(Class   pcType, Object   oid);
58  
59      /**
60       * Informs the cache to expect that the given pcType will be used as a key
61       * for the outer map in subsequent <code>putEntry</code> operations.
62       * @param pcType class of instance, used as key in outer map.
63       */
64      public void addPCType(Class   pcType);
65  
66      /**
67       * Removes the map for the given pcType and all its elements.
68       * @param pcType class of instance, used as key in outer map.
69       */
70      public void removePCType(Class   pcType);
71  }
72
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