SqlConstraintFactory


1   /*
2   // This software is subject to the terms of the Common Public License
3   // Agreement, available at the following URL:
4   // http://www.opensource.org/licenses/cpl.html.
5   // Copyright (C) 2004-2005 TONBELLER AG
6   // All Rights Reserved.
7   // You must accept the terms of that agreement to use this software.
8   */
9   package mondrian.rolap;
10  
11  import java.util.List  ;
12  
13  import mondrian.olap.Evaluator;
14  import mondrian.olap.Level;
15  import mondrian.olap.MondrianProperties;
16  import mondrian.rolap.sql.MemberChildrenConstraint;
17  import mondrian.rolap.sql.TupleConstraint;
18  
19  /**
20   * Creates the right constraint for common tasks.
21   *
22   * @author av
23   * @since Nov 21, 2005
24   */
25  public class SqlConstraintFactory {
26  
27      boolean enabled = MondrianProperties.instance().EnableNativeNonEmpty.get();
28  
29      private static final SqlConstraintFactory instance = new SqlConstraintFactory();
30  
31      /** singleton */
32      private SqlConstraintFactory() {
33      }
34  
35      public static SqlConstraintFactory instance() {
36          return instance;
37      }
38  
39      public MemberChildrenConstraint getMemberChildrenConstraint(Evaluator context) {
40          if (!enabled || !SqlContextConstraint.isValidContext(context))
41              return DefaultMemberChildrenConstraint.instance();
42          return new SqlContextConstraint((RolapEvaluator) context, false);
43      }
44  
45      public TupleConstraint getLevelMembersConstraint(Evaluator context) {
46          return getLevelMembersConstraint(context, null);
47      }
48  
49      public TupleConstraint getLevelMembersConstraint(
50          Evaluator context,
51          Level [] levels) {
52          if (!enabled ||
53              !SqlContextConstraint.isValidContext(context, false, levels))
54          {
55              return DefaultTupleConstraint.instance();
56          }
57          return new SqlContextConstraint((RolapEvaluator) context, false);
58      }
59  
60      public MemberChildrenConstraint getChildByNameConstraint(
61          RolapMember parent,
62          String   childName)
63      {
64          // ragged hierarchies span multiple levels, so SQL WHERE does not work there
65          if (!enabled || parent.getHierarchy().isRagged()) {
66              return DefaultMemberChildrenConstraint.instance();
67          }
68          return new ChildByNameConstraint(childName);
69      }
70  
71      /**
72       * Returns a constraint that allows to read all children of multiple parents
73       * at once using a LevelMember query style. This does not work
74       * for parent/child hierarchies.
75       */
76      public TupleConstraint getDescendantsConstraint(
77          List  <RolapMember> parentMembers,
78          MemberChildrenConstraint mcc)
79      {
80          return new DescendantsConstraint(parentMembers, mcc);
81      }
82  }
83  
84  // End SqlConstraintFactory.java
85
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