MemberCache


1   /*
2   // $Id: //open/mondrian/src/main/mondrian/rolap/MemberCache.java#12 $
3   // This software is subject to the terms of the Common Public License
4   // Agreement, available at the following URL:
5   // http://www.opensource.org/licenses/cpl.html.
6   // Copyright (C) 2001-2002 Kana Software, Inc.
7   // Copyright (C) 2001-2007 Julian Hyde and others
8   // All Rights Reserved.
9   // You must accept the terms of that agreement to use this software.
10  //
11  // jhyde, 22 December, 2001
12  */
13  
14  package mondrian.rolap;
15  
16  import java.util.List  ;
17  
18  import mondrian.rolap.sql.TupleConstraint;
19  import mondrian.rolap.sql.MemberChildrenConstraint;
20  
21  /**
22   * A <code>MemberCache</code> can retrieve members based upon their parent and
23   * name.
24   *
25   * @author jhyde
26   * @since 22 December, 2001
27   * @version $Id: //open/mondrian/src/main/mondrian/rolap/MemberCache.java#12 $
28   */
29  interface MemberCache {
30      /**
31       * Creates a key with which to {@link #getMember(Object)} or
32       * {@link #putMember(Object, RolapMember)} the
33       * {@link RolapMember} with a given parent and key.
34       */
35      Object   makeKey(RolapMember parent, Object   key);
36  
37      /**
38       * Retrieves the {@link RolapMember} with a given key (created by
39       * {@link #makeKey}).
40       */
41      RolapMember getMember(Object   key);
42  
43      /**
44       * Retrieves the {@link RolapMember} with a given key (created by
45       * {@link #makeKey}).  It is possible to disable the checking of the
46       * cache status with this call.
47       */
48      RolapMember getMember(Object   key, boolean mustCheckCacheStatus);
49  
50      /**
51       * Replaces the {@link RolapMember} with a given key (created by {@link
52       * #makeKey}). Returns the previous member with that key, or null.
53       */
54      Object   putMember(Object   key, RolapMember value);
55  
56      /**
57       * returns the children of <code>member</code> if they are currently in the cache.
58       * Otherwise returns null. The children may be garbage collected as soon as the
59       * returned list may be garbage collected.
60       *
61       * @param parent the parent member
62       * @param constraint the condition that was used when the members were
63       *    fetched. May be null for all members (no constraint)
64       */
65      List  <RolapMember> getChildrenFromCache(
66          RolapMember parent,
67          MemberChildrenConstraint constraint);
68  
69      /**
70       * returns the members of <code>level</code> if they are currently in the cache.
71       * Otherwise returns null. The members may be garbage collected as soon as the
72       * returned list may be garbage collected.
73       * @param level the level whose members should be fetched
74       * @param constraint the condition that was used when the members were
75       *   fetched. May be null for all members (no constraint)
76       */
77      List   getLevelMembersFromCache(RolapLevel level, TupleConstraint constraint);
78  
79      /**
80       * Registers that the children of <code>member</code> are
81       * <code>children</code> (a list of {@link RolapMember}s).
82       * @param member the parent member
83       * @param constraint the condition that was used when the members were
84       *   fetched. May be null for all members (no constraint)
85       */
86      void putChildren(
87          RolapMember member,
88          MemberChildrenConstraint constraint,
89          List  <RolapMember> children);
90  }
91  
92  
93  // End MemberCache.java
94
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