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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: Neg.java 468655 2006-10-28 07:12:06Z minchau $
     20  */
     21 package org.apache.xpath.operations;
     22 
     23 import org.apache.xpath.XPathContext;
     24 import org.apache.xpath.objects.XNumber;
     25 import org.apache.xpath.objects.XObject;
     26 
     27 /**
     28  * The unary '-' operation expression executer.
     29  */
     30 public class Neg extends UnaryOperation
     31 {
     32     static final long serialVersionUID = -6280607702375702291L;
     33 
     34   /**
     35    * Apply the operation to two operands, and return the result.
     36    *
     37    *
     38    * @param right non-null reference to the evaluated right operand.
     39    *
     40    * @return non-null reference to the XObject that represents the result of the operation.
     41    *
     42    * @throws javax.xml.transform.TransformerException
     43    */
     44   public XObject operate(XObject right) throws javax.xml.transform.TransformerException
     45   {
     46     return new XNumber(-right.num());
     47   }
     48 
     49   /**
     50    * Evaluate this operation directly to a double.
     51    *
     52    * @param xctxt The runtime execution context.
     53    *
     54    * @return The result of the operation as a double.
     55    *
     56    * @throws javax.xml.transform.TransformerException
     57    */
     58   public double num(XPathContext xctxt)
     59           throws javax.xml.transform.TransformerException
     60   {
     61 
     62     return -(m_right.num(xctxt));
     63   }
     64 
     65 }
     66