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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  }