001 /*
002 // $Id: //open/mondrian/src/main/mondrian/rolap/MemberCache.java#14 $
003 // This software is subject to the terms of the Common Public License
004 // Agreement, available at the following URL:
005 // http://www.opensource.org/licenses/cpl.html.
006 // Copyright (C) 2001-2002 Kana Software, Inc.
007 // Copyright (C) 2001-2007 Julian Hyde and others
008 // All Rights Reserved.
009 // You must accept the terms of that agreement to use this software.
010 //
011 // jhyde, 22 December, 2001
012 */
013
014 package mondrian.rolap;
015
016 import java.util.List;
017
018 import mondrian.rolap.sql.TupleConstraint;
019 import mondrian.rolap.sql.MemberChildrenConstraint;
020
021 /**
022 * A <code>MemberCache</code> can retrieve members based upon their parent and
023 * name.
024 *
025 * @author jhyde
026 * @since 22 December, 2001
027 * @version $Id: //open/mondrian/src/main/mondrian/rolap/MemberCache.java#14 $
028 */
029 interface MemberCache {
030 /**
031 * Creates a key with which to {@link #getMember(Object)} or
032 * {@link #putMember(Object, RolapMember)} the
033 * {@link RolapMember} with a given parent and key.
034 *
035 * @param parent Parent member
036 * @param key Key of member within parent
037 * @return key with which to address this member in the cache
038 */
039 Object makeKey(RolapMember parent, Object key);
040
041 /**
042 * Retrieves the {@link RolapMember} with a given key.
043 *
044 * @param key cache key, created by {@link #makeKey}
045 * @return member with a given cache key
046 */
047 RolapMember getMember(Object key);
048
049 /**
050 * Retrieves the {@link RolapMember} with a given key.
051 *
052 * @param key cache key, created by {@link #makeKey}
053 * @param mustCheckCacheStatus If {@code true}, do not check cache status
054 * @return member with a given cache key
055 */
056 RolapMember getMember(Object key, boolean mustCheckCacheStatus);
057
058 /**
059 * Replaces the {@link RolapMember} with a given key and returns the
060 * previous member if any.
061 *
062 * @param key cache key, created by {@link #makeKey}
063 * @param member new member
064 * @return Previous member with that key, or null.
065 */
066 Object putMember(Object key, RolapMember member);
067
068 /**
069 * Returns whether the cache supports removing selected items. If it does,
070 * it is valid to call the {@link #removeMember(Object)} and
071 * {@link #removeMemberAndDescendants(Object)} methods.
072 *
073 * <p>REVIEW: remove isMutable and move removeMember and
074 * removeMemberAndDescendants to new interface MutableMemberCache
075 *
076 * @return true if the cache supports removing selected items.
077 */
078 boolean isMutable();
079
080 /**
081 * Removes the {@link RolapMember} with a given key from the cache.
082 * Returns the previous member with that key, or null.
083 * Optional operation: see {@link #isMutable}.
084 *
085 * @param key cache key, created by {@link #makeKey}
086 * @return previous member with that key, or null
087 */
088 RolapMember removeMember(Object key);
089
090 /**
091 * Removes the designated {@link RolapMember} and all its descendants.
092 * Returns the previous member with that key, or null.
093 * Optional operation: see {@link #isMutable}.
094 *
095 * @param key cache key, created by {@link #makeKey}
096 * @return previous member with that key, or null
097 */
098 RolapMember removeMemberAndDescendants(Object key);
099
100 /**
101 * Returns the children of <code>member</code> if they are currently in the
102 * cache, otherwise returns null.
103 *
104 * <p>The children may be garbage collected as
105 * soon as the returned list may be garbage collected.</p>
106 *
107 * @param parent the parent member
108 * @param constraint the condition that was used when the members were
109 * fetched. May be null for all members (no constraint)
110 * @return list of children, or null if not in cache
111 */
112 List<RolapMember> getChildrenFromCache(
113 RolapMember parent,
114 MemberChildrenConstraint constraint);
115
116 /**
117 * Returns the members of <code>level</code> if they are currently in the
118 * cache, otherwise returns null.
119 *
120 * <p>The members may be garbage collected as soon as the
121 * returned list may be garbage collected.</p>
122 *
123 * @param level the level whose members should be fetched
124 * @param constraint the condition that was used when the members were
125 * fetched. May be null for all members (no constraint)
126 * @return members of level, or null if not in cache
127 */
128 List<RolapMember> getLevelMembersFromCache(
129 RolapLevel level,
130 TupleConstraint constraint);
131
132 /**
133 * Registers that the children of <code>member</code> are
134 * <code>children</code> (a list of {@link RolapMember}s).
135 *
136 * @param member the parent member
137 * @param constraint the condition that was used when the members were
138 * fetched. May be null for all members (no constraint)
139 * @param children list of children
140 */
141 void putChildren(
142 RolapMember member,
143 MemberChildrenConstraint constraint,
144 List<RolapMember> children);
145 }
146
147
148 // End MemberCache.java