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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.PropertyDescriptor;
    8   import net.sourceforge.pmd.ast.ASTBlock;
    9   import net.sourceforge.pmd.ast.ASTClassOrInterfaceType;
    10  import net.sourceforge.pmd.ast.ASTCompilationUnit;
    11  import net.sourceforge.pmd.ast.ASTLocalVariableDeclaration;
    12  import net.sourceforge.pmd.ast.ASTMethodDeclaration;
    13  import net.sourceforge.pmd.ast.ASTName;
    14  import net.sourceforge.pmd.ast.ASTReferenceType;
    15  import net.sourceforge.pmd.ast.ASTTryStatement;
    16  import net.sourceforge.pmd.ast.ASTType;
    17  import net.sourceforge.pmd.ast.ASTVariableDeclaratorId;
    18  import net.sourceforge.pmd.ast.Node;
    19  import net.sourceforge.pmd.properties.StringProperty;
    20
    21  import java.util.ArrayList;
    22  import java.util.HashSet;
    23  import java.util.List;
    24  import java.util.Map;
    25  import java.util.Set;
    26  import java.util.StringTokenizer;
    27
    28  /**
    29   * Makes sure you close your database connections. It does this by
    30   * looking for code patterned like this:
    31   * <pre>
    32   *  Connection c = X;
    33   *  try {
    34   *   // do stuff, and maybe catch something
    35   *  } finally {
    36   *   c.close();
    37   *  }
    38   *
    39   *  @author original author unknown
    40   *  @author Contribution from Pierre Mathien
    41   * </pre>
    42   */
    43  public class CloseResource extends AbstractRule {
    44
    45      private Set<String> types = new HashSet<String>();
    46
    47      private Set<String> closeTargets = new HashSet<String>();
    48      private static final PropertyDescriptor closeTargetsDescriptor = new StringProperty("closeTargets",
    49              "Methods which may close this resource", "", 1.0f);
    50
    51      private static final PropertyDescriptor typesDescriptor = new StringProperty("types",
    52              "Types that are affected by this rule", "", 2.0f);
    53
    54      private static final Map<String, PropertyDescriptor> propertyDescriptorsByName = asFixedMap(new PropertyDescriptor[] { typesDescriptor, closeTargetsDescriptor });
    55
    56      protected Map<String, PropertyDescriptor> propertiesByName() {
    57          return propertyDescriptorsByName;
    58      }
    59
    60      public Object visit(ASTCompilationUnit node, Object data) {
    61          if (closeTargets.isEmpty() && getStringProperty(closeTargetsDescriptor) != null) {
    62              for (StringTokenizer st = new StringTokenizer(getStringProperty(closeTargetsDescriptor), ","); st.hasMoreTokens();) {
    63                  closeTargets.add(st.nextToken());
    64              }
    65          }
    66          if (types.isEmpty() && getStringProperty(typesDescriptor) != null) {
    67              for (StringTokenizer st = new StringTokenizer(getStringProperty(typesDescriptor), ","); st.hasMoreTokens();) {
    68                  types.add(st.nextToken());
    69              }
    70          }
    71          return super.visit(node, data);
    72      }
    73
    74      public Object visit(ASTMethodDeclaration node, Object data) {
    75          List<ASTLocalVariableDeclaration> vars = node.findChildrenOfType(ASTLocalVariableDeclaration.class);
    76          List<ASTVariableDeclaratorId> ids = new ArrayList<ASTVariableDeclaratorId>();
    77
    78          // find all variable references to Connection objects
    79          for (ASTLocalVariableDeclaration var: vars) {
    80              ASTType type = var.getTypeNode();
    81
    82              if (type.jjtGetChild(0) instanceof ASTReferenceType) {
    83                  ASTReferenceType ref = (ASTReferenceType) type.jjtGetChild(0);
    84                  if (ref.jjtGetChild(0) instanceof ASTClassOrInterfaceType) {
    85                      ASTClassOrInterfaceType clazz = (ASTClassOrInterfaceType) ref.jjtGetChild(0);
    86                      if (types.contains(clazz.getImage())) {
    87                          ASTVariableDeclaratorId id = (ASTVariableDeclaratorId) var.jjtGetChild(1).jjtGetChild(0);
    88                          ids.add(id);
    89                      }
    90                  }
    91              }
    92          }
    93
    94          // if there are connections, ensure each is closed.
    95          for (ASTVariableDeclaratorId x : ids) {
    96              ensureClosed((ASTLocalVariableDeclaration) x.jjtGetParent().jjtGetParent(), x, data);
    97          }
    98          return data;
    99      }
    100
    101     private void ensureClosed(ASTLocalVariableDeclaration var,
    102                               ASTVariableDeclaratorId id, Object data) {
    103         // What are the chances of a Connection being instantiated in a
    104         // for-loop init block? Anyway, I'm lazy!
    105         String target = id.getImage() + ".close";
    106         Node n = var;
    107
    108         while (!(n instanceof ASTBlock)) {
    109             n = n.jjtGetParent();
    110         }
    111
    112         ASTBlock top = (ASTBlock) n;
    113
    114         List<ASTTryStatement> tryblocks = new ArrayList<ASTTryStatement>();
    115         top.findChildrenOfType(ASTTryStatement.class, tryblocks, true);
    116
    117         boolean closed = false;
    118
    119         // look for try blocks below the line the variable was
    120         // introduced and make sure there is a .close call in a finally
    121         // block.
    122         for (ASTTryStatement t : tryblocks) {
    123             if ((t.getBeginLine() > id.getBeginLine()) && (t.hasFinally())) {
    124                 ASTBlock f = (ASTBlock) t.getFinally().jjtGetChild(0);
    125                 List<ASTName> names = new ArrayList<ASTName>();
    126                 f.findChildrenOfType(ASTName.class, names, true);
    127                 for (ASTName oName : names) {
    128                     String name = oName.getImage();
    129                     if (name.equals(target) || closeTargets.contains(name)) {
    130                         closed = true;
    131                     }
    132                 }
    133             }
    134         }
    135
    136         // if all is not well, complain
    137         if (!closed) {
    138             ASTType type = (ASTType) var.jjtGetChild(0);
    139             ASTReferenceType ref = (ASTReferenceType) type.jjtGetChild(0);
    140             ASTClassOrInterfaceType clazz = (ASTClassOrInterfaceType) ref.jjtGetChild(0);
    141             addViolation(data, id, clazz.getImage());
    142         }
    143     }
    144 }