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


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 // Copyright (c) 1998, 2006, Oracle. All rights reserved.
22 package oracle.toplink.essentials.internal.parsing;
23
24 /**
25  * INTERNAL
26  * <p><b>Purpose</b>: Superclass for Aggregate Nodes
27  * <p><b>Responsibilities</b>:<ul>
28  * <li> Apply itself to a query correctly
29  * </ul>
30  * @author Jon Driscoll
31  * @since TopLink 5.0
32  */
33
34 import oracle.toplink.essentials.expressions.Expression;
35
36 public abstract class AggregateNode extends Node {
37
38     private boolean distinct = false;
39
40     /**
41      * INTERNAL
42      */
43     public String JavaDoc resolveAttribute() {
44         Node arg = getLeft();
45         return arg.isDotNode() ? ((DotNode)arg).resolveAttribute() : null;
46     }
47
48     /**
49      * resolveClass: Answer the class associated with my left node.
50      */
51     public Class JavaDoc resolveClass(GenerationContext context) {
52         return getLeft().resolveClass(context);
53     }
54
55     /**
56      * INTERNAL
57      * Is this node an Aggregate node
58      */
59     public boolean isAggregateNode() {
60         return true;
61     }
62
63     /** */
64     public boolean usesDistinct() {
65         return distinct;
66     }
67
68     /** */
69     public void setDistinct(boolean distinct) {
70         this.distinct = distinct;
71     }
72
73     /** */
74     protected Expression getArgumentExpression(GenerationContext context) {
75         Expression arg = getLeft().generateExpression(context);
76         if (usesDistinct()) {
77             arg = arg.distinct();
78         }
79         return arg;
80     }
81 }
82
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