View Javadoc

    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultEqualityExpr.java,v 1.13 2005/06/28 13:44:44 elharo Exp $
    3    * $Revision: 1.13 $
    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: DefaultEqualityExpr.java,v 1.13 2005/06/28 13:44:44 elharo Exp $
    60   */
    61
    62
    63
    64  package org.jaxen.expr;
    65
    66  import java.util.Iterator;
    67  import java.util.List;
    68  import org.jaxen.Context;
    69  import org.jaxen.JaxenException;
    70  import org.jaxen.Navigator;
    71  import org.jaxen.function.BooleanFunction;
    72  import org.jaxen.function.NumberFunction;
    73  import org.jaxen.function.StringFunction;
    74
    75  abstract class DefaultEqualityExpr extends DefaultTruthExpr implements EqualityExpr
    76    {
    77    DefaultEqualityExpr( Expr lhs, Expr rhs )
    78      {
    79      super( lhs, rhs );
    80      }
    81
    82    public String toString()
    83      {
    84      return "[(DefaultEqualityExpr): " + getLHS() + ", " + getRHS() + "]";
    85      }
    86
    87    public Object evaluate( Context context ) throws JaxenException
    88      {
    89      Object lhsValue = getLHS().evaluate( context );
    90      Object rhsValue = getRHS().evaluate( context );
    91
    92      if( lhsValue == null || rhsValue == null )
    93        {
    94        return Boolean.FALSE;
    95        }
    96
    97      Navigator nav = context.getNavigator();
    98
    99      if( bothAreSets( lhsValue, rhsValue ) )
    100       {
    101       return evaluateSetSet( (List) lhsValue, (List) rhsValue, nav );
    102       }
    103     else if ( eitherIsSet( lhsValue, rhsValue ) )
    104       {
    105       if ( isSet( lhsValue ) )
    106         {
    107         return evaluateSetSet( (List) lhsValue, convertToList( rhsValue ), nav );
    108         }
    109       else
    110         {
    111         return evaluateSetSet( convertToList( lhsValue ), (List) rhsValue, nav );
    112         }
    113       }
    114     else
    115       {
    116       return evaluateObjectObject( lhsValue, rhsValue, nav ) ? Boolean.TRUE : Boolean.FALSE;
    117       }
    118     }
    119
    120   private Boolean evaluateSetSet( List lhsSet, List rhsSet, Navigator nav )
    121     {
    122     if( setIsEmpty( lhsSet ) || setIsEmpty( rhsSet ) )
    123       {
    124       return Boolean.FALSE;
    125       }
    126
    127     for( Iterator lhsIterator = lhsSet.iterator(); lhsIterator.hasNext(); )
    128       {
    129       Object lhs = lhsIterator.next();
    130
    131       for( Iterator rhsIterator = rhsSet.iterator(); rhsIterator.hasNext(); )
    132         {
    133         Object rhs = rhsIterator.next();
    134
    135         if( evaluateObjectObject( lhs, rhs, nav ) )
    136           {
    137           return Boolean.TRUE;
    138           }
    139         }
    140       }
    141
    142     return Boolean.FALSE;
    143     }
    144
    145   private boolean evaluateObjectObject( Object lhs, Object rhs, Navigator nav )
    146     {
    147     if( eitherIsBoolean( lhs, rhs ) )
    148       {
    149       return evaluateObjectObject( BooleanFunction.evaluate( lhs, nav ),
    150                                    BooleanFunction.evaluate( rhs, nav ) );
    151       }
    152     else if( eitherIsNumber( lhs, rhs ) )
    153       {
    154       return evaluateObjectObject( NumberFunction.evaluate( lhs,
    155                                                             nav ),
    156                                    NumberFunction.evaluate( rhs,
    157                                                             nav ) );
    158       }
    159     else
    160       {
    161       return evaluateObjectObject( StringFunction.evaluate( lhs,
    162                                                             nav ),
    163                                    StringFunction.evaluate( rhs,
    164                                                             nav ) );
    165       }
    166     }
    167
    168   protected abstract boolean evaluateObjectObject( Object lhs, Object rhs );
    169   }