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


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 import oracle.toplink.essentials.expressions.*;
25
26 /**
27  * INTERNAL
28  * <p><b>Purpose</b>: Represent a '<>' in EJBQL
29  * <p><b>Responsibilities</b>:<ul>
30  * <li> Generate the correct expression for an '<>' in EJBQL
31  * </ul>
32  * @author Jon Driscoll and Joel Lucuik
33  * @since TopLink 4.0
34  */
35 public class NotEqualsNode extends BinaryOperatorNode {
36
37     /**
38      * EqualsNode constructor comment.
39      */
40     public NotEqualsNode() {
41         super();
42     }
43
44     /**
45      * INTERNAL
46      * Validate node and calculates its type.
47      */
48     public void validate(ParseTreeContext context) {
49         super.validate(context);
50         TypeHelper typeHelper = context.getTypeHelper();
51         setType(typeHelper.getBooleanType());
52     }
53
54     /**
55      * Resolve the expression. The steps are:
56      * 1. Set the expressionBuilder for the left and right nodes
57      * 2. Generate the expression for the left node
58      * 3. Add the .notEqual to the where clause returned from step 2
59      * 4. Generate the expression for the right side and use it as the parameter for the .equals()
60      * 5. Return the completed where clause to the caller
61      */
62     public Expression generateExpression(GenerationContext context) {
63         Expression whereClause = getLeft().generateExpression(context);
64         whereClause = whereClause.notEqual(getRight().generateExpression(context));
65         return whereClause;
66     }
67
68     /**
69      * INTERNAL
70      * Get the string representation of this node.
71      */
72     public String JavaDoc getAsString() {
73         return left.getAsString() + " <> " + right.getAsString();
74     }
75 }
76
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