001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements. See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership. The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the  "License");
007     * you may not use this file except in compliance with the License.
008     * You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    /*
019     * $Id: Plus.java 468655 2006-10-28 07:12:06Z minchau $
020     */
021    package org.apache.xpath.operations;
022    
023    import org.apache.xpath.XPathContext;
024    import org.apache.xpath.objects.XNumber;
025    import org.apache.xpath.objects.XObject;
026    
027    /**
028     * The '+' operation expression executer.
029     */
030    public class Plus extends Operation
031    {
032        static final long serialVersionUID = -4492072861616504256L;
033    
034      /**
035       * Apply the operation to two operands, and return the result.
036       *
037       *
038       * @param left non-null reference to the evaluated left operand.
039       * @param right non-null reference to the evaluated right operand.
040       *
041       * @return non-null reference to the XObject that represents the result of the operation.
042       *
043       * @throws javax.xml.transform.TransformerException
044       */
045      public XObject operate(XObject left, XObject right)
046              throws javax.xml.transform.TransformerException
047      {
048        return new XNumber(left.num() + right.num());
049      }
050      
051      /**
052       * Evaluate this operation directly to a double.
053       *
054       * @param xctxt The runtime execution context.
055       *
056       * @return The result of the operation as a double.
057       *
058       * @throws javax.xml.transform.TransformerException
059       */
060      public double num(XPathContext xctxt)
061              throws javax.xml.transform.TransformerException
062      {
063    
064        return (m_right.num(xctxt) + m_left.num(xctxt));
065      }
066    
067    }