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1   package net.sourceforge.pmd.rules;
2   
3   import net.sourceforge.pmd.AbstractRule;
4   import net.sourceforge.pmd.ast.ASTClassOrInterfaceDeclaration;
5   import net.sourceforge.pmd.ast.ASTClassOrInterfaceType;
6   import net.sourceforge.pmd.ast.ASTFormalParameter;
7   import net.sourceforge.pmd.ast.ASTFormalParameters;
8   import net.sourceforge.pmd.ast.ASTImplementsList;
9   import net.sourceforge.pmd.ast.ASTMethodDeclarator;
10  import net.sourceforge.pmd.ast.SimpleNode;
11  
12  import java.util.List;
13  
14  public class OverrideBothEqualsAndHashcode extends AbstractRule {
15  
16      private boolean implementsComparable = false;
17  
18      private boolean containsEquals = false;
19  
20      private boolean containsHashCode = false;
21      
22      private SimpleNode nodeFound = null;
23  
24      public Object visit(ASTClassOrInterfaceDeclaration node, Object data) {
25          if (node.isInterface()) {
26              return data;
27          }
28          super.visit(node, data);
29          if (!implementsComparable && (containsEquals ^ containsHashCode)) {
30              if(nodeFound == null){
31                  nodeFound = node;
32              }
33              addViolation(data, nodeFound);
34          }
35          implementsComparable = containsEquals = containsHashCode = false;
36          nodeFound = null;
37          return data;
38      }
39  
40      public Object visit(ASTImplementsList node, Object data) {
41          for (int ix = 0; ix < node.jjtGetNumChildren(); ix++) {
42              if (node.jjtGetChild(ix).getClass().equals(ASTClassOrInterfaceType.class)
43                      && ((SimpleNode) node.jjtGetChild(ix)).hasImageEqualTo("Comparable")) {
44                  implementsComparable = true;
45                  return data;
46              }
47          }
48          return super.visit(node, data);
49      }
50  
51      public Object visit(ASTMethodDeclarator node, Object data) {
52          if (implementsComparable) {
53              return data;
54          }
55  
56          int iFormalParams = 0;
57          String paramName = null;
58          for (int ix = 0; ix < node.jjtGetNumChildren(); ix++) {
59              SimpleNode sn = (SimpleNode) node.jjtGetChild(ix);
60              if (sn.getClass().equals(ASTFormalParameters.class)) {
61                  List allParams = ((ASTFormalParameters) sn).findChildrenOfType(ASTFormalParameter.class);
62                  for (int i = 0; i < allParams.size(); i++) {
63                      iFormalParams++;
64                      ASTFormalParameter formalParam = (ASTFormalParameter) allParams.get(i);
65                      ASTClassOrInterfaceType param = (ASTClassOrInterfaceType) formalParam.getFirstChildOfType(ASTClassOrInterfaceType.class);
66                      if (param != null) {
67                          paramName = param.getImage();
68                      }
69                  }
70              }
71          }
72  
73          if (iFormalParams == 0 && node.hasImageEqualTo("hashCode")) {
74              containsHashCode = true;
75              nodeFound = node;
76          } else if (iFormalParams == 1 && node.hasImageEqualTo("equals") && ("Object".equals(paramName) || "java.lang.Object".equals(paramName))) {
77              containsEquals = true;
78              nodeFound = node;
79          }
80          return super.visit(node, data);
81      }
82  
83  }