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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 }