01: /**
02: * com.mckoi.database.GroupResolver 14 Jul 2000
03: *
04: * Mckoi SQL Database ( http://www.mckoi.com/database )
05: * Copyright (C) 2000, 2001, 2002 Diehl and Associates, Inc.
06: *
07: * This program is free software; you can redistribute it and/or
08: * modify it under the terms of the GNU General Public License
09: * Version 2 as published by the Free Software Foundation.
10: *
11: * This program is distributed in the hope that it will be useful,
12: * but WITHOUT ANY WARRANTY; without even the implied warranty of
13: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14: * GNU General Public License Version 2 for more details.
15: *
16: * You should have received a copy of the GNU General Public License
17: * Version 2 along with this program; if not, write to the Free Software
18: * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19: *
20: * Change Log:
21: *
22: *
23: */package com.mckoi.database;
24:
25: import com.mckoi.util.IntegerVector;
26:
27: /**
28: * Similar to VariableResolver, this method is used by grouping Functions to
29: * find information about the current group being evaluated (used for
30: * evaluating aggregate functions).
31: *
32: * @author Tobias Downer
33: */
34:
35: public interface GroupResolver {
36:
37: /**
38: * A number that uniquely identifies this group from all the others in the
39: * set of groups.
40: */
41: public int groupID();
42:
43: /**
44: * The total number of set items in this group.
45: */
46: public int size();
47:
48: /**
49: * Returns the value of a variable of a group. The set index signifies the
50: * set item of the group. For example, if the group contains 10 items, then
51: * set_index may be between 0 and 9. Return types must be either
52: * a String, BigDecimal or Boolean.
53: */
54: public TObject resolve(Variable variable, int set_index);
55:
56: /**
57: * Returns a VariableResolver that can be used to resolve variable in the
58: * get set of the group. The object returned is undefined after the next
59: * call to this method.
60: */
61: public VariableResolver getVariableResolver(int set_index);
62:
63: }
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