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Java > Open Source Codes > oracle > toplink > essentials > internal > parsing > SizeNode


1 /*
2  * The contents of this file are subject to the terms
3  * of the Common Development and Distribution License
4  * (the "License"). You may not use this file except
5  * in compliance with the License.
6  *
7  * You can obtain a copy of the license at
8  * glassfish/bootstrap/legal/CDDLv1.0.txt or
9  * https://glassfish.dev.java.net/public/CDDLv1.0.html.
10  * See the License for the specific language governing
11  * permissions and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL
14  * HEADER in each file and include the License file at
15  * glassfish/bootstrap/legal/CDDLv1.0.txt. If applicable,
16  * add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your
18  * own identifying information: Portions Copyright [yyyy]
19  * [name of copyright owner]
20  */
21
22 // Copyright (c) 1998, 2005, Oracle. All rights reserved.
23 package oracle.toplink.essentials.internal.parsing;
24
25 import oracle.toplink.essentials.expressions.*;
26 import oracle.toplink.essentials.exceptions.EJBQLException;
27
28 /**
29  * INTERNAL
30  * <p><b>Purpose</b>: Represent a SIZE function
31  * <p><b>Responsibilities</b>:<ul>
32  * <li> Generate the correct expression for SIZE
33  * </ul>
34  */
35 public class SizeNode extends ArithmeticFunctionNode {
36
37     /**
38      * Return a new SizeNode.
39      */
40     public SizeNode() {
41         super();
42     }
43
44     /**
45      * INTERNAL
46      * Validate node and calculate its type.
47      */
48     public void validate(ParseTreeContext context) {
49         if (left != null) {
50             left.validate(context);
51         }
52         TypeHelper typeHelper = context.getTypeHelper();
53         setType(typeHelper.getIntType());
54     }
55
56     /**
57      * INTERNAL
58      * Generate the TopLink expression for this node
59      */
60     public Expression generateExpression(GenerationContext context) {
61         DotNode dotNode = (DotNode)getLeft();
62         Node prefix = dotNode.getLeft();
63         String JavaDoc variableName = ((AttributeNode)dotNode.getRight()).getAttributeName();
64
65         // check whether variable denotes a collection valued field
66 if (!dotNode.endsWithCollectionField(context)) {
67             throw EJBQLException.invalidSizeArgument(variableName);
68         }
69         Expression whereClause = prefix.generateExpression(context);
70         whereClause = whereClause.size(variableName);
71         return whereClause;
72     }
73
74 }
75
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