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Java > Open Source Codes > org > objectweb > medor > filter > lib > Sum


1 /**
2  * MEDOR: Middleware Enabling Distributed Object Requests
3  *
4  * Copyright (C) 2001-2003 France Telecom R&D
5  * Contact: alexandre.lefebvre@rd.francetelecom.com
6  *
7  * This library is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * This library is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with this library; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  *
21  * Initial developers: M. Alia, S. Chassande-Barrioz, A. Lefebvre
22  */
23
24 package org.objectweb.medor.filter.lib;
25
26 import org.objectweb.jorm.type.api.PTypeSpace;
27 import org.objectweb.medor.expression.api.Expression;
28 import org.objectweb.medor.expression.api.ExpressionException;
29 import org.objectweb.medor.expression.api.MalformedExpressionException;
30 import org.objectweb.medor.expression.api.Operand;
31 import org.objectweb.medor.expression.api.Operator;
32 import org.objectweb.medor.expression.api.ParameterOperand;
33 import org.objectweb.medor.expression.lib.BasicVariableOperand;
34
35 /**
36  * Sum aggregate function.
37  * <p> Sum applies to :
38  * <ol>
39  * <li>a FieldOperand, which is part of a NestedField.</li>
40  * <li>a Collection of values (TupleCollection), specifying which Field
41  * is to be aggregated</li>
42  * <li>a Collection of values (Java Collection)</li>
43  * </ol>
44  * @author Alexandre Lefebvre
45  */
46 public class Sum extends BasicAggregateOperator {
47
48     public Sum(Expression e) {
49         super(e.getType(), e);
50     }
51
52     public Sum(Expression e, boolean distinct) {
53         super(e.getType(), e, distinct);
54         if (e.getType() == PTypeSpace.FLOAT) {
55            type = PTypeSpace.DOUBLE;
56         }
57     }
58
59     public String JavaDoc getOperatorString() {
60         return Operator.SUM;
61     }
62
63     public Operand compileExpression()
64             throws ExpressionException, MalformedExpressionException {
65         if (expressions[0] != null) {
66             expressions[0].compileExpression();
67                 result = new BasicVariableOperand(expressions[0].getType());
68                 verified = true;
69         }
70         else
71         // Operands not yet assigned
72 throw new MalformedExpressionException("null children value");
73         return result;
74     }
75
76     public org.objectweb.medor.expression.api.Operand evaluate(ParameterOperand[] pos, Object JavaDoc o)
77             throws ExpressionException {
78         throw new ExpressionException("Implementation of Avg by MEDOR not yet implemented");
79     }
80 }
81
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