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Java > Open Source Codes > org > eclipse > jdt > internal > corext > refactoring > code > TempAssignmentFinder


1 /*******************************************************************************
2  * Copyright (c) 2000, 2005 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Eclipse Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/epl-v10.html
7  *
8  * Contributors:
9  * IBM Corporation - initial API and implementation
10  *******************************************************************************/
11 package org.eclipse.jdt.internal.corext.refactoring.code;
12
13 import org.eclipse.jdt.core.dom.ASTNode;
14 import org.eclipse.jdt.core.dom.ASTVisitor;
15 import org.eclipse.jdt.core.dom.Assignment;
16 import org.eclipse.jdt.core.dom.IVariableBinding;
17 import org.eclipse.jdt.core.dom.Name;
18 import org.eclipse.jdt.core.dom.PostfixExpression;
19 import org.eclipse.jdt.core.dom.PrefixExpression;
20 import org.eclipse.jdt.core.dom.SimpleName;
21 import org.eclipse.jdt.core.dom.VariableDeclaration;
22 import org.eclipse.jdt.core.dom.PrefixExpression.Operator;
23
24 public class TempAssignmentFinder extends ASTVisitor{
25     private ASTNode fFirstAssignment;
26     private IVariableBinding fTempBinding;
27     
28     TempAssignmentFinder(VariableDeclaration tempDeclaration){
29         fTempBinding= tempDeclaration.resolveBinding();
30     }
31     
32     private boolean isNameReferenceToTemp(Name name){
33         return fTempBinding == name.resolveBinding();
34     }
35         
36     private boolean isAssignmentToTemp(Assignment assignment){
37         if (fTempBinding == null)
38             return false;
39             
40         if (! (assignment.getLeftHandSide() instanceof Name))
41             return false;
42         Name ref= (Name)assignment.getLeftHandSide();
43         return isNameReferenceToTemp(ref);
44     }
45     
46     boolean hasAssignments(){
47         return fFirstAssignment != null;
48     }
49     
50     ASTNode getFirstAssignment(){
51         return fFirstAssignment;
52     }
53     
54     //-- visit methods
55
56     public boolean visit(Assignment assignment) {
57         if (! isAssignmentToTemp(assignment))
58             return true;
59         
60         fFirstAssignment= assignment;
61         return false;
62     }
63     
64     public boolean visit(PostfixExpression postfixExpression) {
65         if (postfixExpression.getOperand() == null)
66             return true;
67         if (! (postfixExpression.getOperand() instanceof SimpleName))
68             return true;
69         SimpleName simpleName= (SimpleName)postfixExpression.getOperand();
70         if (! isNameReferenceToTemp(simpleName))
71             return true;
72         
73         fFirstAssignment= postfixExpression;
74         return false;
75     }
76     
77     public boolean visit(PrefixExpression prefixExpression) {
78         if (prefixExpression.getOperand() == null)
79             return true;
80         if (! (prefixExpression.getOperand() instanceof SimpleName))
81             return true;
82         if (! prefixExpression.getOperator().equals(Operator.DECREMENT) &&
83             ! prefixExpression.getOperator().equals(Operator.INCREMENT))
84             return true;
85         SimpleName simpleName= (SimpleName)prefixExpression.getOperand();
86         if (! isNameReferenceToTemp(simpleName))
87             return true;
88         
89         fFirstAssignment= prefixExpression;
90         return false;
91     }
92 }
93
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