View Javadoc

    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultTruthExpr.java,v 1.9 2005/06/28 13:44:44 elharo Exp $
    3    * $Revision: 1.9 $
    4    * $Date: 2005/06/28 13:44:44 $
    5    *
    6    * ====================================================================
    7    *
    8    * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
    9    * All rights reserved.
    10   *
    11   * Redistribution and use in source and binary forms, with or without
    12   * modification, are permitted provided that the following conditions
    13   * are met:
    14   *
    15   * 1. Redistributions of source code must retain the above copyright
    16   *    notice, this list of conditions, and the following disclaimer.
    17   *
    18   * 2. Redistributions in binary form must reproduce the above copyright
    19   *    notice, this list of conditions, and the disclaimer that follows
    20   *    these conditions in the documentation and/or other materials
    21   *    provided with the distribution.
    22   *
    23   * 3. The name "Jaxen" must not be used to endorse or promote products
    24   *    derived from this software without prior written permission.  For
    25   *    written permission, please contact license@jaxen.org.
    26   *
    27   * 4. Products derived from this software may not be called "Jaxen", nor
    28   *    may "Jaxen" appear in their name, without prior written permission
    29   *    from the Jaxen Project Management (pm@jaxen.org).
    30   *
    31   * In addition, we request (but do not require) that you include in the
    32   * end-user documentation provided with the redistribution and/or in the
    33   * software itself an acknowledgement equivalent to the following:
    34   *     "This product includes software developed by the
    35   *      Jaxen Project <http://www.jaxen.org/>."
    36   * Alternatively, the acknowledgment may be graphical using the logos
    37   * available at http://www.jaxen.org/
    38   *
    39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
    40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
    43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
    46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
    49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    50   * SUCH DAMAGE.
    51   *
    52   * ====================================================================
    53   * This software consists of voluntary contributions made by many
    54   * individuals on behalf of the Jaxen Project and was originally
    55   * created by bob mcwhirter <bob@werken.com> and
    56   * James Strachan <jstrachan@apache.org>.  For more information on the
    57   * Jaxen Project, please see <http://www.jaxen.org/>.
    58   *
    59   * $Id: DefaultTruthExpr.java,v 1.9 2005/06/28 13:44:44 elharo Exp $
    60   */
    61
    62
    63
    64  package org.jaxen.expr;
    65
    66  import java.util.List;
    67
    68  abstract class DefaultTruthExpr extends DefaultBinaryExpr
    69  {
    70      DefaultTruthExpr(Expr lhs,
    71                              Expr rhs)
    72      {
    73          super( lhs,
    74                 rhs );
    75      }
    76
    77      public String toString()
    78      {
    79          return "[(DefaultTruthExpr): " + getLHS() + ", " + getRHS() + "]";
    80      }
    81
    82      protected boolean bothAreSets(Object lhs,
    83                                    Object rhs)
    84      {
    85          return ( lhs instanceof List
    86                   &&
    87                   rhs instanceof List );
    88      }
    89
    90      protected boolean eitherIsSet(Object lhs,
    91                                    Object rhs)
    92      {
    93          return ( lhs instanceof List
    94                   ||
    95                   rhs instanceof List );
    96      }
    97
    98      protected boolean isSet(Object obj)
    99      {
    100         return ( obj instanceof List );
    101     }
    102
    103     protected boolean setIsEmpty( List set )
    104       {
    105       return (set == null || set.size() == 0);
    106       }
    107
    108     protected boolean eitherIsBoolean(Object lhs,
    109                                       Object rhs)
    110     {
    111         return ( lhs instanceof Boolean
    112                  ||
    113                  rhs instanceof Boolean );
    114     }
    115
    116     protected boolean bothAreBoolean(Object lhs,
    117                                      Object rhs)
    118     {
    119         return ( lhs instanceof Boolean
    120                  &&
    121                  rhs instanceof Boolean );
    122     }
    123
    124     protected boolean eitherIsNumber(Object lhs,
    125                                      Object rhs)
    126     {
    127         return ( lhs instanceof Number
    128                  ||
    129                  rhs instanceof Number );
    130     }
    131
    132 }
    133