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1   /***
2    * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
3    */
4   package net.sourceforge.pmd.rules;
5   
6   import net.sourceforge.pmd.AbstractRule;
7   import net.sourceforge.pmd.ast.ASTClassOrInterfaceDeclaration;
8   import net.sourceforge.pmd.symboltable.NameOccurrence;
9   import net.sourceforge.pmd.symboltable.VariableNameDeclaration;
10  
11  import java.util.Iterator;
12  import java.util.List;
13  import java.util.Map;
14  
15  public class UnusedPrivateFieldRule extends AbstractRule {
16  
17      public Object visit(ASTClassOrInterfaceDeclaration node, Object data) {
18          Map vars = node.getScope().getVariableDeclarations();
19          for (Iterator i = vars.keySet().iterator(); i.hasNext();) {
20              VariableNameDeclaration decl = (VariableNameDeclaration) i.next();
21              if (!decl.getAccessNodeParent().isPrivate() || isOK(decl.getImage())) {
22                  continue;
23              }
24              if (!actuallyUsed((List) vars.get(decl))) {
25                  addViolation(data, decl.getNode(), decl.getImage());
26              }
27          }
28          return super.visit(node, data);
29      }
30  
31      private boolean actuallyUsed(List usages) {
32          for (Iterator j = usages.iterator(); j.hasNext();) {
33              NameOccurrence nameOccurrence = (NameOccurrence) j.next();
34              if (!nameOccurrence.isOnLeftHandSide()) {
35                  return true;
36              }
37          }
38          return false;
39      }
40  
41      private boolean isOK(String image) {
42          return image.equals("serialVersionUID") || image.equals("serialPersistentFields") || image.equals("IDENT");
43      }
44  }