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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.ASTClassOrInterfaceType;
    8   import net.sourceforge.pmd.ast.ASTFieldDeclaration;
    9   import net.sourceforge.pmd.ast.ASTMethodDeclaration;
    10  import net.sourceforge.pmd.ast.ASTSynchronizedStatement;
    11  import net.sourceforge.pmd.ast.ASTVariableDeclaratorId;
    12  import net.sourceforge.pmd.ast.SimpleNode;
    13  import net.sourceforge.pmd.symboltable.NameOccurrence;
    14
    15  import java.util.HashSet;
    16  import java.util.Set;
    17
    18  /**
    19   * Using a DateFormatter (SimpleDateFormatter) which is static can cause
    20   * unexpected results when used in a multi threaded environment. This rule will
    21   * find static (Simple)DateFormatters which are used in an unsynchronized
    22   * manner.
    23   * Refer to these Bug Parade issues:
    24   * <a href="http://developer.java.sun.com/developer/bugParade/bugs/4093418.html">4093418</a>
    25   * <a href="http://developer.java.sun.com/developer/bugParade/bugs/4228335.html">4228335</a>
    26   * <a href="http://developer.java.sun.com/developer/bugParade/bugs/4261469.html">4261469</a>
    27   * see RFE1020790 - Check for SimpleDateFormat as singleton http://sourceforge.net/tracker/index.php?func=detail&aid=1020790&group_id=56262&atid=479924
    28   * @author Allan Caplan
    29   */
    30  public class UnsynchronizedStaticDateFormatter extends AbstractRule {
    31
    32      private static Set<String> targets = new HashSet<String>();
    33      static {
    34          targets.add("DateFormat");
    35          targets.add("SimpleDateFormat");
    36          targets.add("java.text.DateFormat");
    37          targets.add("java.text.SimpleDateFormat");
    38      }
    39
    40      public Object visit(ASTFieldDeclaration node, Object data) {
    41          if (!node.isStatic()) {
    42              return data;
    43          }
    44          ASTClassOrInterfaceType cit = node.getFirstChildOfType(ASTClassOrInterfaceType.class);
    45          if (cit == null || !targets.contains(cit.getImage())) {
    46              return data;
    47          }
    48          ASTVariableDeclaratorId var = node.getFirstChildOfType(ASTVariableDeclaratorId.class);
    49          for (NameOccurrence occ: var.getUsages()) {
    50              SimpleNode n = occ.getLocation();
    51              if (n.getFirstParentOfType(ASTSynchronizedStatement.class) != null) {
    52                  continue;
    53              }
    54              ASTMethodDeclaration method = n.getFirstParentOfType(ASTMethodDeclaration.class);
    55              if (method != null && !method.isSynchronized()) {
    56                  addViolation(data, n);
    57              }
    58          }
    59          return data;
    60      }
    61  }