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    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/FloorFunction.java,v 1.10 2005/06/28 13:44:45 elharo Exp $
    3    * $Revision: 1.10 $
    4    * $Date: 2005/06/28 13:44:45 $
    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: FloorFunction.java,v 1.10 2005/06/28 13:44:45 elharo Exp $
    60   */
    61
    62
    63  package org.jaxen.function;
    64
    65  import java.util.List;
    66
    67  import org.jaxen.Context;
    68  import org.jaxen.Function;
    69  import org.jaxen.FunctionCallException;
    70  import org.jaxen.Navigator;
    71
    72  /***
    73   * <p><b>4.4</b> <code><i>number</i> floor(<i>number</i>)</code></p>
    74   *
    75   *
    76   * <blockquote src="http://www.w3.org/TR/xpath">
    77   * The floor function returns the largest (closest to positive infinity)
    78   * number that is not greater than the argument and that is an integer....
    79   * If the argument is NaN, then NaN is returned.
    80   * If the argument is positive infinity, then positive infinity is returned.
    81   * If the argument is negative infinity, then negative infinity is returned.
    82   * If the argument is positive zero, then positive zero is returned.
    83   * If the argument is negative zero, then negative zero is returned.
    84   * If the argument is greater than zero, but less than 1, then positive zero is returned.
    85   * </blockquote>
    86   *
    87   * @author bob mcwhirter (bob @ werken.com)
    88   *
    89   * @see <a href="http://www.w3.org/TR/xpath#function-floor" target="_top">Section 4.4 of the XPath Specification</a>
    90   * @see <a href="http://www.w3.org/1999/11/REC-xpath-19991116-errata/"  target="_top">XPath Errata</a>
    91   */
    92  public class FloorFunction implements Function
    93  {
    94
    95      /***
    96       * Create a new <code>FloorFunction</code> object.
    97       */
    98      public FloorFunction() {}
    99
    100     /*** Returns the largest integer less than or equal to a number.
    101      *
    102      * @param context the context at the point in the
    103      *         expression when the function is called
    104      * @param args a list with exactly one item which will be converted to a
    105      *     <code>Double</code> as if by the XPath <code>number()</code> function
    106      *
    107      * @return a <code>Double</code> containing the largest integer less than or equal
    108      *     to <code>args.get(0)</code>
    109      *
    110      * @throws FunctionCallException if <code>args</code> has more or less than one item
    111      */
    112     public Object call(Context context,
    113                        List args) throws FunctionCallException
    114     {
    115         if (args.size() == 1)
    116         {
    117             return evaluate( args.get(0),
    118                              context.getNavigator() );
    119         }
    120
    121         throw new FunctionCallException( "floor() requires one argument." );
    122     }
    123
    124     /*** Returns the largest integer less than or equal to the argument.
    125      * If necessary, the argument is first converted to a <code>Double</code>
    126      * as if by the XPath <code>number()</code> function.
    127      *
    128      * @param obj the object whose floor is returned
    129      * @param nav ignored
    130      *
    131      * @return a <code>Double</code> containing the largest integer less
    132      *     than or equal to <code>obj</code>
    133      */
    134     public static Double evaluate(Object obj,
    135                                   Navigator nav)
    136     {
    137         Double value = NumberFunction.evaluate( obj,
    138                                                 nav );
    139
    140         return new Double( Math.floor( value.doubleValue() ) );
    141     }
    142 }
    143