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1 | /******************************************************************************* |
2 | * Copyright (c) 2000, 2011 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.core.runtime.Assert; | |
14 | ||
15 | import org.eclipse.jdt.core.dom.ASTVisitor; | |
16 | import org.eclipse.jdt.core.dom.FieldAccess; | |
17 | import org.eclipse.jdt.core.dom.IBinding; | |
18 | import org.eclipse.jdt.core.dom.IMethodBinding; | |
19 | import org.eclipse.jdt.core.dom.ITypeBinding; | |
20 | import org.eclipse.jdt.core.dom.IVariableBinding; | |
21 | import org.eclipse.jdt.core.dom.MethodInvocation; | |
22 | import org.eclipse.jdt.core.dom.Modifier; | |
23 | import org.eclipse.jdt.core.dom.Name; | |
24 | import org.eclipse.jdt.core.dom.QualifiedName; | |
25 | import org.eclipse.jdt.core.dom.SimpleName; | |
26 | import org.eclipse.jdt.core.dom.SuperFieldAccess; | |
27 | import org.eclipse.jdt.core.dom.SuperMethodInvocation; | |
28 | import org.eclipse.jdt.core.dom.ThisExpression; | |
29 | ||
30 | import org.eclipse.jdt.internal.corext.dom.fragments.ASTFragmentFactory; | |
31 | import org.eclipse.jdt.internal.corext.dom.fragments.IExpressionFragment; | |
32 | ||
33 | class ConstantChecks { | |
34 | private static abstract class ExpressionChecker extends ASTVisitor { | |
35 | ||
36 | private final IExpressionFragment fExpression; | |
37 | protected boolean fResult= true; | |
38 | ||
39 | public ExpressionChecker(IExpressionFragment ex) { | |
40 | fExpression= ex; | |
41 | } | |
42 | public boolean check() { | |
43 | fResult= true; | |
44 | fExpression.getAssociatedNode().accept(this); | |
45 | return fResult; | |
46 | } | |
47 | } | |
48 | ||
49 | private static class LoadTimeConstantChecker extends ExpressionChecker { | |
50 | public LoadTimeConstantChecker(IExpressionFragment ex) { | |
51 | super(ex); | |
52 | } | |
53 | ||
54 | @Override | |
55 | public boolean visit(SuperFieldAccess node) { | |
56 | fResult= false; | |
57 | return false; | |
58 | } | |
59 | @Override | |
60 | public boolean visit(SuperMethodInvocation node) { | |
61 | fResult= false; | |
62 | return false; | |
63 | } | |
64 | @Override | |
65 | public boolean visit(ThisExpression node) { | |
66 | fResult= false; | |
67 | return false; | |
68 | } | |
69 | @Override | |
70 | public boolean visit(FieldAccess node) { | |
71 | fResult&= new LoadTimeConstantChecker((IExpressionFragment) ASTFragmentFactory.createFragmentForFullSubtree(node.getExpression())).check(); | |
72 | return false; | |
73 | } | |
74 | @Override | |
75 | public boolean visit(MethodInvocation node) { | |
76 | if(node.getExpression() == null) { | |
77 | visitName(node.getName()); | |
78 | } else { | |
79 | fResult&= new LoadTimeConstantChecker((IExpressionFragment) ASTFragmentFactory.createFragmentForFullSubtree(node.getExpression())).check(); | |
80 | } | |
81 | ||
82 | return false; | |
83 | } | |
84 | @Override | |
85 | public boolean visit(QualifiedName node) { | |
86 | return visitName(node); | |
87 | } | |
88 | @Override | |
89 | public boolean visit(SimpleName node) { | |
90 | return visitName(node); | |
91 | } | |
92 | ||
93 | private boolean visitName(Name name) { | |
94 | fResult&= checkName(name); | |
95 | return false; //Do not descend further | |
96 | } | |
97 | ||
98 | private boolean checkName(Name name) { | |
99 | IBinding binding= name.resolveBinding(); | |
100 | if (binding == null) | |
101 | return true; /* If the binding is null because of compile errors etc., | |
102 | scenarios which may have been deemed unacceptable in | |
103 | the presence of semantic information will be admitted. */ | |
104 | ||
105 | // If name represents a member: | |
106 | if (binding instanceof IVariableBinding || binding instanceof IMethodBinding) | |
107 | return isMemberReferenceValidInClassInitialization(name); | |
108 | else if (binding instanceof ITypeBinding) | |
109 | return ! ((ITypeBinding) binding).isTypeVariable(); | |
110 | else { | |
111 | /* IPackageBinding is not expected, as a package name not | |
112 | used as a type name prefix is not expected in such an | |
113 | expression. Other types are not expected either. | |
114 | */ | |
115 | Assert.isTrue(false); | |
116 | return true; | |
117 | } | |
118 | } | |
119 | ||
120 | private boolean isMemberReferenceValidInClassInitialization(Name name) { | |
121 | IBinding binding= name.resolveBinding(); | |
122 | Assert.isTrue(binding instanceof IVariableBinding || binding instanceof IMethodBinding); | |
123 | ||
124 | if(name instanceof SimpleName) | |
125 | return Modifier.isStatic(binding.getModifiers()); | |
126 | else { | |
127 | Assert.isTrue(name instanceof QualifiedName); | |
128 | return checkName(((QualifiedName) name).getQualifier()); | |
129 | } | |
130 | } | |
131 | } | |
132 | ||
133 | private static class StaticFinalConstantChecker extends ExpressionChecker { | |
134 | public StaticFinalConstantChecker(IExpressionFragment ex) { | |
135 | super(ex); | |
136 | } | |
137 | ||
138 | @Override | |
139 | public boolean visit(SuperFieldAccess node) { | |
140 | fResult= false; | |
141 | return false; | |
142 | } | |
143 | @Override | |
144 | public boolean visit(SuperMethodInvocation node) { | |
145 | fResult= false; | |
146 | return false; | |
147 | } | |
148 | @Override | |
149 | public boolean visit(ThisExpression node) { | |
150 | fResult= false; | |
151 | return false; | |
152 | } | |
153 | ||
154 | @Override | |
155 | public boolean visit(QualifiedName node) { | |
156 | return visitName(node); | |
157 | } | |
158 | @Override | |
159 | public boolean visit(SimpleName node) { | |
160 | return visitName(node); | |
161 | } | |
162 | private boolean visitName(Name name) { | |
163 | IBinding binding= name.resolveBinding(); | |
164 | if(binding == null) { | |
165 | /* If the binding is null because of compile errors etc., | |
166 | scenarios which may have been deemed unacceptable in | |
167 | the presence of semantic information will be admitted. | |
168 | Descend deeper. | |
169 | */ | |
170 | return true; | |
171 | } | |
172 | ||
173 | int modifiers= binding.getModifiers(); | |
174 | if(binding instanceof IVariableBinding) { | |
175 | if (!(Modifier.isStatic(modifiers) && Modifier.isFinal(modifiers))) { | |
176 | fResult= false; | |
177 | return false; | |
178 | } | |
179 | } else if(binding instanceof IMethodBinding) { | |
180 | if (!Modifier.isStatic(modifiers)) { | |
181 | fResult= false; | |
182 | return false; | |
183 | } | |
184 | } else if(binding instanceof ITypeBinding) { | |
185 | return false; // It's o.k. Don't descend deeper. | |
186 | ||
187 | } else { | |
188 | /* IPackageBinding is not expected, as a package name not | |
189 | used as a type name prefix is not expected in such an | |
190 | expression. Other types are not expected either. | |
191 | */ | |
192 | Assert.isTrue(false); | |
193 | return false; | |
194 | } | |
195 | ||
196 | //Descend deeper: | |
197 | return true; | |
198 | } | |
199 | } | |
200 | ||
201 | public static boolean isStaticFinalConstant(IExpressionFragment ex) { | |
202 | return new StaticFinalConstantChecker(ex).check(); | |
203 | } | |
204 | ||
205 | public static boolean isLoadTimeConstant(IExpressionFragment ex) { | |
206 | return new LoadTimeConstantChecker(ex).check(); | |
207 | } | |
208 | } |