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Java > Open Source Codes > net > sourceforge > pmd > rules > design > CompareObjectsWithEquals


1 package net.sourceforge.pmd.rules.design;
2
3 import net.sourceforge.pmd.AbstractRule;
4 import net.sourceforge.pmd.ast.ASTEqualityExpression;
5 import net.sourceforge.pmd.ast.ASTInitializer;
6 import net.sourceforge.pmd.ast.ASTName;
7 import net.sourceforge.pmd.ast.Node;
8 import net.sourceforge.pmd.ast.SimpleNode;
9 import net.sourceforge.pmd.symboltable.VariableNameDeclaration;
10
11 public class CompareObjectsWithEquals extends AbstractRule {
12
13     private boolean hasName(Node n) {
14         return n.jjtGetNumChildren() > 0 && n.jjtGetChild(0) instanceof ASTName;
15     }
16     
17     public Object JavaDoc visit(ASTEqualityExpression node, Object JavaDoc data) {
18         // skip if either child is not a simple name
19 if (!hasName(((SimpleNode) node.jjtGetChild(0)).jjtGetChild(0)) || !hasName(((SimpleNode) node.jjtGetChild(1)).jjtGetChild(0))) {
20             return data;
21         }
22
23         // skip if either is a qualified name
24 if (isQualifiedName((SimpleNode) node.jjtGetChild(0).jjtGetChild(0).jjtGetChild(0))
25             || isQualifiedName((SimpleNode) node.jjtGetChild(1).jjtGetChild(0).jjtGetChild(0))) {
26             return data;
27         }
28
29         // skip static initializers... missing some cases here
30 if (!node.getParentsOfType(ASTInitializer.class).isEmpty()) {
31             return data;
32         }
33
34         ASTName n0 = (ASTName) node.jjtGetChild(0).jjtGetChild(0).jjtGetChild(0);
35         ASTName n1 = (ASTName) node.jjtGetChild(1).jjtGetChild(0).jjtGetChild(0);
36
37         if (n0.getNameDeclaration() instanceof VariableNameDeclaration && n1.getNameDeclaration() instanceof VariableNameDeclaration) {
38             VariableNameDeclaration nd0 = (VariableNameDeclaration) n0.getNameDeclaration();
39             VariableNameDeclaration nd1 = (VariableNameDeclaration) n1.getNameDeclaration();
40
41             // skip array dereferences... this misses some cases
42 // FIXME catch comparisons btwn array elements of reference types
43 if (nd0.isArray() || nd1.isArray()) {
44                 return data;
45             }
46
47             if (nd0.isReferenceType() && nd1.isReferenceType()) {
48                 addViolation(data, node);
49             }
50         }
51
52         return data;
53     }
54 }
55
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