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      1 /*
      2  * Licensed to the Apache Software Foundation (ASF) under one
      3  * or more contributor license agreements. See the NOTICE file
      4  * distributed with this work for additional information
      5  * regarding copyright ownership. The ASF licenses this file
      6  * to you under the Apache License, Version 2.0 (the  "License");
      7  * you may not use this file except in compliance with the License.
      8  * You may obtain a copy of the License at
      9  *
     10  *     http://www.apache.org/licenses/LICENSE-2.0
     11  *
     12  * Unless required by applicable law or agreed to in writing, software
     13  * distributed under the License is distributed on an "AS IS" BASIS,
     14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     15  * See the License for the specific language governing permissions and
     16  * limitations under the License.
     17  */
     18 /*
     19  * $Id: XBoolean.java 469368 2006-10-31 04:41:36Z minchau $
     20  */
     21 package org.apache.xpath.objects;
     22 
     23 /**
     24  * This class represents an XPath boolean object, and is capable of
     25  * converting the boolean to other types, such as a string.
     26  * @xsl.usage advanced
     27  */
     28 public class XBoolean extends XObject
     29 {
     30     static final long serialVersionUID = -2964933058866100881L;
     31 
     32   /**
     33    * A true boolean object so we don't have to keep creating them.
     34    * @xsl.usage internal
     35    */
     36   public static final XBoolean S_TRUE = new XBooleanStatic(true);
     37 
     38   /**
     39    * A true boolean object so we don't have to keep creating them.
     40    * @xsl.usage internal
     41    */
     42   public static final XBoolean S_FALSE = new XBooleanStatic(false);
     43 
     44   /** Value of the object.
     45    *  @serial         */
     46   private final boolean m_val;
     47 
     48   /**
     49    * Construct a XBoolean object.
     50    *
     51    * @param b Value of the boolean object
     52    */
     53   public XBoolean(boolean b)
     54   {
     55 
     56     super();
     57 
     58     m_val = b;
     59   }
     60 
     61   /**
     62    * Construct a XBoolean object.
     63    *
     64    * @param b Value of the boolean object
     65    */
     66   public XBoolean(Boolean b)
     67   {
     68 
     69     super();
     70 
     71     m_val = b.booleanValue();
     72     setObject(b);
     73   }
     74 
     75 
     76   /**
     77    * Tell that this is a CLASS_BOOLEAN.
     78    *
     79    * @return type of CLASS_BOOLEAN
     80    */
     81   public int getType()
     82   {
     83     return CLASS_BOOLEAN;
     84   }
     85 
     86   /**
     87    * Given a request type, return the equivalent string.
     88    * For diagnostic purposes.
     89    *
     90    * @return type string "#BOOLEAN"
     91    */
     92   public String getTypeString()
     93   {
     94     return "#BOOLEAN";
     95   }
     96 
     97   /**
     98    * Cast result object to a number.
     99    *
    100    * @return numeric value of the object value
    101    */
    102   public double num()
    103   {
    104     return m_val ? 1.0 : 0.0;
    105   }
    106 
    107   /**
    108    * Cast result object to a boolean.
    109    *
    110    * @return The object value as a boolean
    111    */
    112   public boolean bool()
    113   {
    114     return m_val;
    115   }
    116 
    117   /**
    118    * Cast result object to a string.
    119    *
    120    * @return The object's value as a string
    121    */
    122   public String str()
    123   {
    124     return m_val ? "true" : "false";
    125   }
    126 
    127   /**
    128    * Return a java object that's closest to the representation
    129    * that should be handed to an extension.
    130    *
    131    * @return The object's value as a java object
    132    */
    133   public Object object()
    134   {
    135     if(null == m_obj)
    136       setObject(new Boolean(m_val));
    137     return m_obj;
    138   }
    139 
    140   /**
    141    * Tell if two objects are functionally equal.
    142    *
    143    * @param obj2 Object to compare to this
    144    *
    145    * @return True if the two objects are equal
    146    *
    147    * @throws javax.xml.transform.TransformerException
    148    */
    149   public boolean equals(XObject obj2)
    150   {
    151 
    152     // In order to handle the 'all' semantics of
    153     // nodeset comparisons, we always call the
    154     // nodeset function.
    155     if (obj2.getType() == XObject.CLASS_NODESET)
    156       return obj2.equals(this);
    157 
    158     try
    159     {
    160       return m_val == obj2.bool();
    161     }
    162     catch(javax.xml.transform.TransformerException te)
    163     {
    164       throw new org.apache.xml.utils.WrappedRuntimeException(te);
    165     }
    166   }
    167 
    168 }
    169