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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.design;
5   
6   import net.sourceforge.pmd.AbstractRule;
7   import net.sourceforge.pmd.ast.ASTClassOrInterfaceBodyDeclaration;
8   import net.sourceforge.pmd.ast.ASTClassOrInterfaceDeclaration;
9   import net.sourceforge.pmd.ast.ASTConstructorDeclaration;
10  import net.sourceforge.pmd.ast.ASTDoStatement;
11  import net.sourceforge.pmd.ast.ASTForStatement;
12  import net.sourceforge.pmd.ast.ASTMethodDeclaration;
13  import net.sourceforge.pmd.ast.ASTTryStatement;
14  import net.sourceforge.pmd.ast.ASTVariableInitializer;
15  import net.sourceforge.pmd.ast.ASTWhileStatement;
16  import net.sourceforge.pmd.ast.SimpleNode;
17  import net.sourceforge.pmd.symboltable.NameOccurrence;
18  import net.sourceforge.pmd.symboltable.VariableNameDeclaration;
19  
20  import java.util.HashSet;
21  import java.util.Iterator;
22  import java.util.List;
23  import java.util.Map;
24  import java.util.Set;
25  import java.util.ArrayList;
26  
27  /***
28   * @author Olander
29   */
30  public class ImmutableField extends AbstractRule {
31  
32      private static final int MUTABLE = 0;
33      private static final int IMMUTABLE = 1;
34      private static final int CHECKDECL = 2;
35  
36      public Object visit(ASTClassOrInterfaceDeclaration node, Object data) {
37          Map vars = node.getScope().getVariableDeclarations();
38          List constructors = findAllConstructors(node);
39          for (Iterator i = vars.keySet().iterator(); i.hasNext();) {
40              VariableNameDeclaration field = (VariableNameDeclaration) i.next();
41              if (field.getAccessNodeParent().isStatic() || !field.getAccessNodeParent().isPrivate() || field.getAccessNodeParent().isFinal()) {
42                  continue;
43              }
44  
45              int result = initializedInConstructor((List) vars.get(field), new HashSet(constructors));
46              if (result == MUTABLE) {
47                  continue;
48              }
49              if (result == IMMUTABLE || (result == CHECKDECL && initializedWhenDeclared(field))) {
50                  addViolation(data, field.getNode(), field.getImage());
51              }
52          }
53          return super.visit(node, data);
54      }
55  
56      private boolean initializedWhenDeclared(VariableNameDeclaration field) {
57          return !field.getAccessNodeParent().findChildrenOfType(ASTVariableInitializer.class).isEmpty();
58      }
59  
60      private int initializedInConstructor(List usages, Set allConstructors) {
61          int result = MUTABLE, methodInitCount = 0;
62          Set consSet = new HashSet();
63          for (Iterator j = usages.iterator(); j.hasNext();) {
64              NameOccurrence occ = (NameOccurrence) j.next();
65              if (occ.isOnLeftHandSide() || occ.isSelfAssignment()) {
66                  SimpleNode node = occ.getLocation();
67                  SimpleNode constructor = (SimpleNode) node.getFirstParentOfType(ASTConstructorDeclaration.class);
68                  if (constructor != null) {
69                      if (inLoopOrTry(node)) {
70                          continue;
71                      }
72                      if (inAnonymousInnerClass(node)) {
73                          methodInitCount++;
74                      } else {
75                          consSet.add(constructor);
76                      }
77                  } else {
78                      if (node.getFirstParentOfType(ASTMethodDeclaration.class) != null) {
79                          methodInitCount++;
80                      }
81                  }
82              }
83          }
84          if (usages.isEmpty() || ((methodInitCount == 0) && consSet.isEmpty())) {
85              result = CHECKDECL;
86          } else {
87              allConstructors.removeAll(consSet);
88              if (allConstructors.isEmpty() && (methodInitCount == 0)) {
89                  result = IMMUTABLE;
90              }
91          }
92          return result;
93      }
94  
95      private boolean inLoopOrTry(SimpleNode node) {
96          return (SimpleNode) node.getFirstParentOfType(ASTTryStatement.class) != null ||
97                  (SimpleNode) node.getFirstParentOfType(ASTForStatement.class) != null ||
98                  (SimpleNode) node.getFirstParentOfType(ASTWhileStatement.class) != null ||
99                  (SimpleNode) node.getFirstParentOfType(ASTDoStatement.class) != null;
100     }
101 
102     private boolean inAnonymousInnerClass(SimpleNode node) {
103         ASTClassOrInterfaceBodyDeclaration parent = (ASTClassOrInterfaceBodyDeclaration) node.getFirstParentOfType(ASTClassOrInterfaceBodyDeclaration.class);
104         return parent != null && parent.isAnonymousInnerClass();
105     }
106 
107     private List findAllConstructors(ASTClassOrInterfaceDeclaration node) {
108         List cons = new ArrayList();
109         node.findChildrenOfType(ASTConstructorDeclaration.class, cons, false);
110         return cons;
111     }
112 }