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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.entrySet().iterator(); i.hasNext();) {
20              Map.Entry entry = (Map.Entry) i.next();
21              VariableNameDeclaration decl = (VariableNameDeclaration) entry.getKey();
22              if (!decl.getAccessNodeParent().isPrivate() || isOK(decl.getImage())) {
23                  continue;
24              }
25              if (!actuallyUsed((List) entry.getValue())) {
26                  addViolation(data, decl.getNode(), decl.getImage());
27              }
28          }
29          return super.visit(node, data);
30      }
31  
32      private boolean actuallyUsed(List usages) {
33          for (Iterator j = usages.iterator(); j.hasNext();) {
34              NameOccurrence nameOccurrence = (NameOccurrence) j.next();
35              if (!nameOccurrence.isOnLeftHandSide()) {
36                  return true;
37              }
38          }
39          return false;
40      }
41  
42      private boolean isOK(String image) {
43          return image.equals("serialVersionUID") || image.equals("serialPersistentFields") || image.equals("IDENT");
44      }
45  }