MemberSource


1   /*
2   // $Id: //open/mondrian/src/main/mondrian/rolap/MemberSource.java#8 $
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) 2001-2006 Julian Hyde and others
8   // All Rights Reserved.
9   // You must accept the terms of that agreement to use this software.
10  //
11  // jhyde, 21 December, 2001
12  */
13  
14  package mondrian.rolap;
15  
16  import java.util.List  ;
17  
18  /**
19   * A <code>MemberSource</code> has the basic operations to read the members of a
20   * {@link RolapHierarchy hierarchy}.
21   *
22   * <p>A <code>MemberSource</code> may optionally support writeback to a
23   * {@link MemberCache}. During the initialization of a
24   * <code>MemberSource</code>, the consumer calls {@link #setCache}; the return
25   * value indicates whether the <code>MemberSource</code> supports
26   * cache-writeback.
27   *
28   * <p>A <dfn>custom member reader</dfn> is a user-defined class which implements
29   * the operations to retrieve members. It either implements the
30   * <code>MemberSource</code> interface, or the derived interface
31   * {@link MemberReader}, which has more operations. In addition to the interface
32   * methods, the class must have a constructor which takes parameters
33   * <code>({@link RolapHierarchy}, {@link java.util.Properties})</code> and
34   * throws no exceptions. To declare a hierarchy based upon the class, use the
35   * <code>memberReaderClass</code> attribute of the
36   * <code>&lt;Hierarchy&gt;</code> element in your XML schema file; the
37   * <code>properties</code> constructor parameter is populated from any
38   * <ocde>&lt;Param name="..." value="..."&gt;</code> child elements.
39   *
40   * @see MemberReader
41   * @see MemberCache
42   *
43   * @author jhyde
44   * @since 21 December, 2001
45   * @version $Id: //open/mondrian/src/main/mondrian/rolap/MemberSource.java#8 $
46   */
47  public interface MemberSource {
48      /**
49       * Returns the hierarchy that this source is reading for.
50       */
51      RolapHierarchy getHierarchy();
52      /**
53       * Sets the cache which this <code>MemberSource</code> will write to.
54       *
55       * <p>Cache-writeback is optional (for example, {@link SqlMemberSource}
56       * supports it, and {@link ArrayMemberSource} does not), and the return
57       * value from this method indicates whether this object supports it.
58       *
59       * <p>If this method returns <code>true</code>, the {@link #getMembers},
60       * {@link #getRootMembers} and {@link #getMemberChildren} methods must
61       * write to the cache, in addition to returning members as a return value.
62       *
63       * @param cache The <code>MemberCache</code> which the caller would like
64       *   this <code>MemberSource</code> to write to.
65       * @return Whether this <code>MemberSource</code> supports cache-writeback.
66       */
67      boolean setCache(MemberCache cache);
68      /**
69       * Returns all members of this hierarchy, sorted by ordinal.
70       *
71       * <p>If this object {@link #setCache supports cache-writeaback}, also
72       * writes these members to the cache.
73       */
74      RolapMember[] getMembers();
75      /**
76       * Returns all members of this hierarchy which do not have a parent,
77       * sorted by ordinal.
78       *
79       * <p>If this object {@link #setCache supports cache-writeback}, also
80       * writes these members to the cache.
81       *
82       * @return {@link List} of {@link RolapMember}s
83       */
84      List  <RolapMember> getRootMembers();
85  
86      /**
87       * Writes all children <code>parentMember</code> to <code>children</code>.
88       *
89       * <p>If this object {@link #setCache supports cache-writeback}, also
90       * writes these members to the cache.
91       */
92      void getMemberChildren(
93          RolapMember parentMember,
94          List  <RolapMember> children);
95  
96      /**
97       * Returns all members which are a child of one of the members in
98       * <code>parentMembers</code>, sorted by ordinal.
99       *
100      * <p>If this object {@link #setCache supports cache-writeaback}, also
101      * writes these members to the cache.
102      */
103     void getMemberChildren(
104         List  <RolapMember> parentMembers,
105         List  <RolapMember> children);
106 
107     /**
108      * Returns an estimate of number of members in this hierarchy.
109      */
110     int getMemberCount();
111 
112     /**
113      * Finds a member based upon its unique name.
114      */
115     RolapMember lookupMember(String  [] uniqueNameParts, boolean failIfNotFound);
116 }
117 
118 // End MemberSource.java
119
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