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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: FunctionDef1Arg.java 468655 2006-10-28 07:12:06Z minchau $
     20  */
     21 package org.apache.xpath.functions;
     22 
     23 import org.apache.xalan.res.XSLMessages;
     24 import org.apache.xml.dtm.DTM;
     25 import org.apache.xml.utils.XMLString;
     26 import org.apache.xpath.XPathContext;
     27 import org.apache.xpath.objects.XString;
     28 import org.apache.xpath.res.XPATHErrorResources;
     29 
     30 /**
     31  * Base class for functions that accept one argument that can be defaulted if
     32  * not specified.
     33  * @xsl.usage advanced
     34  */
     35 public class FunctionDef1Arg extends FunctionOneArg
     36 {
     37     static final long serialVersionUID = 2325189412814149264L;
     38 
     39   /**
     40    * Execute the first argument expression that is expected to return a
     41    * nodeset.  If the argument is null, then return the current context node.
     42    *
     43    * @param xctxt Runtime XPath context.
     44    *
     45    * @return The first node of the executed nodeset, or the current context
     46    *         node if the first argument is null.
     47    *
     48    * @throws javax.xml.transform.TransformerException if an error occurs while
     49    *                                   executing the argument expression.
     50    */
     51   protected int getArg0AsNode(XPathContext xctxt)
     52           throws javax.xml.transform.TransformerException
     53   {
     54 
     55     return (null == m_arg0)
     56            ? xctxt.getCurrentNode() : m_arg0.asNode(xctxt);
     57   }
     58 
     59   /**
     60    * Tell if the expression is a nodeset expression.
     61    * @return true if the expression can be represented as a nodeset.
     62    */
     63   public boolean Arg0IsNodesetExpr()
     64   {
     65     return (null == m_arg0) ? true : m_arg0.isNodesetExpr();
     66   }
     67 
     68   /**
     69    * Execute the first argument expression that is expected to return a
     70    * string.  If the argument is null, then get the string value from the
     71    * current context node.
     72    *
     73    * @param xctxt Runtime XPath context.
     74    *
     75    * @return The string value of the first argument, or the string value of the
     76    *         current context node if the first argument is null.
     77    *
     78    * @throws javax.xml.transform.TransformerException if an error occurs while
     79    *                                   executing the argument expression.
     80    */
     81   protected XMLString getArg0AsString(XPathContext xctxt)
     82           throws javax.xml.transform.TransformerException
     83   {
     84     if(null == m_arg0)
     85     {
     86       int currentNode = xctxt.getCurrentNode();
     87       if(DTM.NULL == currentNode)
     88         return XString.EMPTYSTRING;
     89       else
     90       {
     91         DTM dtm = xctxt.getDTM(currentNode);
     92         return dtm.getStringValue(currentNode);
     93       }
     94 
     95     }
     96     else
     97       return m_arg0.execute(xctxt).xstr();
     98   }
     99 
    100   /**
    101    * Execute the first argument expression that is expected to return a
    102    * number.  If the argument is null, then get the number value from the
    103    * current context node.
    104    *
    105    * @param xctxt Runtime XPath context.
    106    *
    107    * @return The number value of the first argument, or the number value of the
    108    *         current context node if the first argument is null.
    109    *
    110    * @throws javax.xml.transform.TransformerException if an error occurs while
    111    *                                   executing the argument expression.
    112    */
    113   protected double getArg0AsNumber(XPathContext xctxt)
    114           throws javax.xml.transform.TransformerException
    115   {
    116 
    117     if(null == m_arg0)
    118     {
    119       int currentNode = xctxt.getCurrentNode();
    120       if(DTM.NULL == currentNode)
    121         return 0;
    122       else
    123       {
    124         DTM dtm = xctxt.getDTM(currentNode);
    125         XMLString str = dtm.getStringValue(currentNode);
    126         return str.toDouble();
    127       }
    128 
    129     }
    130     else
    131       return m_arg0.execute(xctxt).num();
    132   }
    133 
    134   /**
    135    * Check that the number of arguments passed to this function is correct.
    136    *
    137    * @param argNum The number of arguments that is being passed to the function.
    138    *
    139    * @throws WrongNumberArgsException if the number of arguments is not 0 or 1.
    140    */
    141   public void checkNumberArgs(int argNum) throws WrongNumberArgsException
    142   {
    143     if (argNum > 1)
    144       reportWrongNumberArgs();
    145   }
    146 
    147   /**
    148    * Constructs and throws a WrongNumberArgException with the appropriate
    149    * message for this function object.
    150    *
    151    * @throws WrongNumberArgsException
    152    */
    153   protected void reportWrongNumberArgs() throws WrongNumberArgsException {
    154       throw new WrongNumberArgsException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_ZERO_OR_ONE, null)); //"0 or 1");
    155   }
    156 
    157   /**
    158    * Tell if this expression or it's subexpressions can traverse outside
    159    * the current subtree.
    160    *
    161    * @return true if traversal outside the context node's subtree can occur.
    162    */
    163   public boolean canTraverseOutsideSubtree()
    164   {
    165     return (null == m_arg0) ? false : super.canTraverseOutsideSubtree();
    166   }
    167 }
    168