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1   package net.sourceforge.pmd.rules;
2   
3   import net.sourceforge.pmd.AbstractRule;
4   import net.sourceforge.pmd.RuleContext;
5   import net.sourceforge.pmd.ast.ASTMethodDeclaration;
6   import net.sourceforge.pmd.dfa.IDataFlowNode;
7   import net.sourceforge.pmd.dfa.pathfinder.CurrentPath;
8   import net.sourceforge.pmd.dfa.pathfinder.DAAPathFinder;
9   import net.sourceforge.pmd.dfa.pathfinder.Executable;
10  import net.sourceforge.pmd.dfa.variableaccess.VariableAccess;
11  
12  import java.util.HashMap;
13  import java.util.Iterator;
14  import java.util.Map;
15  
16  public class UselessAssignment extends AbstractRule implements Executable {
17  
18      private RuleContext rc;
19  
20      public Object visit(ASTMethodDeclaration node, Object data) {
21          this.rc = (RuleContext) data;
22  
23  /*
24          IDataFlowNode n1 = node.getDataFlowNode();
25          List f = n1.getFlow();
26          for (Iterator i = f.iterator(); i.hasNext();) {
27              DataFlowNode dfan = (DataFlowNode)i.next();
28              System.out.println(dfan);
29              List va = dfan.getVariableAccess();
30              for (Iterator j = va.iterator(); j.hasNext();) {
31                  VariableAccess o = (VariableAccess)j.next();
32                  System.out.println(o);
33              }
34          }
35  */
36  
37          DAAPathFinder a = new DAAPathFinder(node.getDataFlowNode().getFlow().get(0), this);
38          a.run();
39  
40          return data;
41      }
42  
43      private static class Usage {
44          public int accessType;
45          public IDataFlowNode node;
46  
47          public Usage(int accessType, IDataFlowNode node) {
48              this.accessType = accessType;
49              this.node = node;
50          }
51  
52          public String toString() {
53              return "accessType = " + accessType + ", line = " + node.getLine();
54          }
55      }
56  
57      public void execute(CurrentPath path) {
58          Map<String, Usage> hash = new HashMap<String, Usage>();
59          //System.out.println("path size is " + path.size());
60          for (Iterator<IDataFlowNode> i = path.iterator(); i.hasNext();) {
61              //System.out.println("i = " + i);
62              IDataFlowNode inode = i.next();
63              if (inode.getVariableAccess() == null) {
64                  continue;
65              }
66              for (int j = 0; j < inode.getVariableAccess().size(); j++) {
67                  VariableAccess va = inode.getVariableAccess().get(j);
68                  //System.out.println("inode = " + inode + ", va = " + va);
69                  Usage u = hash.get(va.getVariableName());
70                  if (u != null) {
71                      // At some point investigate and possibly reintroduce this line2 thing
72                      //int line2 = ((Integer) array.get(1)).intValue();
73  
74                      // DD - definition followed by another definition
75                      // FIXME need to check for assignment as well!
76                      if (va.isDefinition() && va.accessTypeMatches(u.accessType)) {
77                          //System.out.println(va.getVariableName() + ":" + u);
78                          addViolation(rc, u.node.getSimpleNode(), va.getVariableName());
79                      }
80  /*                        // UR - ??
81                    else if (last == VariableAccess.UNDEFINITION && va.isReference()) {
82                          //this.rc.getReport().addRuleViolation(createRuleViolation(rc, inode.getSimpleNode(), va.getVariableName(), "UR"));
83                      }
84                      // DU - variable is defined and then goes out of scope
85                      // i.e., unused parameter
86                      else if (last == VariableAccess.DEFINITION && va.isUndefinition()) {
87                          if (inode.getSimpleNode() != null) {
88                              this.rc.getReport().addRuleViolation(createRuleViolation(rc, tmp, va.getVariableName(), "DU"));
89                          }
90                      }
91  */
92                  }
93                  u = new Usage(va.getAccessType(), inode);
94                  hash.put(va.getVariableName(), u);
95              }
96          }
97      }
98  }