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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: Function2Args.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.xpath.Expression;
     25 import org.apache.xpath.ExpressionOwner;
     26 import org.apache.xpath.XPathVisitor;
     27 
     28 /**
     29  * Base class for functions that accept two arguments.
     30  * @xsl.usage advanced
     31  */
     32 public class Function2Args extends FunctionOneArg
     33 {
     34     static final long serialVersionUID = 5574294996842710641L;
     35 
     36   /** The second argument passed to the function (at index 1).
     37    *  @serial  */
     38   Expression m_arg1;
     39 
     40   /**
     41    * Return the second argument passed to the function (at index 1).
     42    *
     43    * @return An expression that represents the second argument passed to the
     44    *         function.
     45    */
     46   public Expression getArg1()
     47   {
     48     return m_arg1;
     49   }
     50 
     51   /**
     52    * This function is used to fixup variables from QNames to stack frame
     53    * indexes at stylesheet build time.
     54    * @param vars List of QNames that correspond to variables.  This list
     55    * should be searched backwards for the first qualified name that
     56    * corresponds to the variable reference qname.  The position of the
     57    * QName in the vector from the start of the vector will be its position
     58    * in the stack frame (but variables above the globalsTop value will need
     59    * to be offset to the current stack frame).
     60    */
     61   public void fixupVariables(java.util.Vector vars, int globalsSize)
     62   {
     63     super.fixupVariables(vars, globalsSize);
     64     if(null != m_arg1)
     65       m_arg1.fixupVariables(vars, globalsSize);
     66   }
     67 
     68 
     69   /**
     70    * Set an argument expression for a function.  This method is called by the
     71    * XPath compiler.
     72    *
     73    * @param arg non-null expression that represents the argument.
     74    * @param argNum The argument number index.
     75    *
     76    * @throws WrongNumberArgsException If the argNum parameter is greater than 1.
     77    */
     78   public void setArg(Expression arg, int argNum)
     79           throws WrongNumberArgsException
     80   {
     81 
     82     // System.out.println("argNum: "+argNum);
     83     if (argNum == 0)
     84       super.setArg(arg, argNum);
     85     else if (1 == argNum)
     86     {
     87       m_arg1 = arg;
     88       arg.exprSetParent(this);
     89     }
     90     else
     91 		  reportWrongNumberArgs();
     92   }
     93 
     94   /**
     95    * Check that the number of arguments passed to this function is correct.
     96    *
     97    *
     98    * @param argNum The number of arguments that is being passed to the function.
     99    *
    100    * @throws WrongNumberArgsException
    101    */
    102   public void checkNumberArgs(int argNum) throws WrongNumberArgsException
    103   {
    104     if (argNum != 2)
    105       reportWrongNumberArgs();
    106   }
    107 
    108   /**
    109    * Constructs and throws a WrongNumberArgException with the appropriate
    110    * message for this function object.
    111    *
    112    * @throws WrongNumberArgsException
    113    */
    114   protected void reportWrongNumberArgs() throws WrongNumberArgsException {
    115       throw new WrongNumberArgsException(XSLMessages.createXPATHMessage("two", null));
    116   }
    117 
    118   /**
    119    * Tell if this expression or it's subexpressions can traverse outside
    120    * the current subtree.
    121    *
    122    * @return true if traversal outside the context node's subtree can occur.
    123    */
    124    public boolean canTraverseOutsideSubtree()
    125    {
    126     return super.canTraverseOutsideSubtree()
    127     ? true : m_arg1.canTraverseOutsideSubtree();
    128    }
    129 
    130   class Arg1Owner implements ExpressionOwner
    131   {
    132     /**
    133      * @see ExpressionOwner#getExpression()
    134      */
    135     public Expression getExpression()
    136     {
    137       return m_arg1;
    138     }
    139 
    140 
    141     /**
    142      * @see ExpressionOwner#setExpression(Expression)
    143      */
    144     public void setExpression(Expression exp)
    145     {
    146     	exp.exprSetParent(Function2Args.this);
    147     	m_arg1 = exp;
    148     }
    149   }
    150 
    151 
    152   /**
    153    * @see org.apache.xpath.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)
    154    */
    155   public void callArgVisitors(XPathVisitor visitor)
    156   {
    157   	super.callArgVisitors(visitor);
    158   	if(null != m_arg1)
    159   		m_arg1.callVisitors(new Arg1Owner(), visitor);
    160   }
    161 
    162   /**
    163    * @see Expression#deepEquals(Expression)
    164    */
    165   public boolean deepEquals(Expression expr)
    166   {
    167   	if(!super.deepEquals(expr))
    168   		return false;
    169 
    170   	if(null != m_arg1)
    171   	{
    172   		if(null == ((Function2Args)expr).m_arg1)
    173   			return false;
    174 
    175   		if(!m_arg1.deepEquals(((Function2Args)expr).m_arg1))
    176   			return false;
    177   	}
    178   	else if(null != ((Function2Args)expr).m_arg1)
    179   		return false;
    180 
    181   	return true;
    182   }
    183 
    184 }
    185