/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: FunctionOneArg.java 468655 2006-10-28 07:12:06Z minchau $
 */
package org.apache.xpath.functions;

import org.apache.xalan.res.XSLMessages;
import org.apache.xpath.Expression;
import org.apache.xpath.ExpressionOwner;
import org.apache.xpath.XPathVisitor;

Base class for functions that accept one argument.
@xsl.usage
advanced/**
 * Base class for functions that accept one argument.
 * @xsl.usage advanced
 */
public class FunctionOneArg extends Function implements ExpressionOwner
{
    static final long serialVersionUID = -5180174180765609758L;

  
The first argument passed to the function (at index 0).
 @serial  /** The first argument passed to the function (at index 0).
   *  @serial  */
  Expression m_arg0;

  
Return the first argument passed to the function (at index 0).
Returns:
An expression that represents the first argument passed to the 
        function./**
   * Return the first argument passed to the function (at index 0).
   *
   * @return An expression that represents the first argument passed to the 
   *         function.
   */
  public Expression getArg0()
  {
    return m_arg0;
  }
  
  
Set an argument expression for a function.  This method is called by the 
XPath compiler.
Params:
arg – non-null expression that represents the argument.
argNum – The argument number index.
Throws:
WrongNumberArgsException – If the argNum parameter is greater than 0./**
   * Set an argument expression for a function.  This method is called by the 
   * XPath compiler.
   *
   * @param arg non-null expression that represents the argument.
   * @param argNum The argument number index.
   *
   * @throws WrongNumberArgsException If the argNum parameter is greater than 0.
   */
  public void setArg(Expression arg, int argNum)
          throws WrongNumberArgsException
  {

    if (0 == argNum)
    {
      m_arg0 = arg;
      arg.exprSetParent(this);
    }
    else
      reportWrongNumberArgs();
  }

  
Check that the number of arguments passed to this function is correct. 
Params:
argNum – The number of arguments that is being passed to the function.
Throws:
WrongNumberArgsException – /**
   * Check that the number of arguments passed to this function is correct. 
   *
   *
   * @param argNum The number of arguments that is being passed to the function.
   *
   * @throws WrongNumberArgsException
   */
  public void checkNumberArgs(int argNum) throws WrongNumberArgsException
  {
    if (argNum != 1)
      reportWrongNumberArgs();
  }

  
Constructs and throws a WrongNumberArgException with the appropriate
message for this function object.
Throws:
WrongNumberArgsException – /**
   * Constructs and throws a WrongNumberArgException with the appropriate
   * message for this function object.
   *
   * @throws WrongNumberArgsException
   */
  protected void reportWrongNumberArgs() throws WrongNumberArgsException {
      throw new WrongNumberArgsException(XSLMessages.createXPATHMessage("one", null));
  }
  
  
Tell if this expression or it's subexpressions can traverse outside 
the current subtree.
Returns:
true if traversal outside the context node's subtree can occur./**
   * Tell if this expression or it's subexpressions can traverse outside 
   * the current subtree.
   * 
   * @return true if traversal outside the context node's subtree can occur.
   */
   public boolean canTraverseOutsideSubtree()
   {
    return m_arg0.canTraverseOutsideSubtree();
   }
   
  
This function is used to fixup variables from QNames to stack frame 
indexes at stylesheet build time.
Params:
vars – List of QNames that correspond to variables.  This list 
should be searched backwards for the first qualified name that 
corresponds to the variable reference qname.  The position of the 
QName in the vector from the start of the vector will be its position 
in the stack frame (but variables above the globalsTop value will need 
to be offset to the current stack frame)./**
   * This function is used to fixup variables from QNames to stack frame 
   * indexes at stylesheet build time.
   * @param vars List of QNames that correspond to variables.  This list 
   * should be searched backwards for the first qualified name that 
   * corresponds to the variable reference qname.  The position of the 
   * QName in the vector from the start of the vector will be its position 
   * in the stack frame (but variables above the globalsTop value will need 
   * to be offset to the current stack frame).
   */
  public void fixupVariables(java.util.Vector vars, int globalsSize)
  {
    if(null != m_arg0)
      m_arg0.fixupVariables(vars, globalsSize);
  }
  
  
See Also:
callVisitors.callVisitors(ExpressionOwner, XPathVisitor)/**
   * @see org.apache.xpath.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)
   */
  public void callArgVisitors(XPathVisitor visitor)
  {
  	if(null != m_arg0)
  		m_arg0.callVisitors(this, visitor);
  }


  
See Also:
getExpression.getExpression()/**
   * @see ExpressionOwner#getExpression()
   */
  public Expression getExpression()
  {
    return m_arg0;
  }

  
See Also:
setExpression.setExpression(Expression)/**
   * @see ExpressionOwner#setExpression(Expression)
   */
  public void setExpression(Expression exp)
  {
  	exp.exprSetParent(this);
  	m_arg0 = exp;
  }
  
  
See Also:
deepEquals.deepEquals(Expression)/**
   * @see Expression#deepEquals(Expression)
   */
  public boolean deepEquals(Expression expr)
  {
  	if(!super.deepEquals(expr))
  		return false;
  		
  	if(null != m_arg0)
  	{
  		if(null == ((FunctionOneArg)expr).m_arg0)
  			return false;
  			
  		if(!m_arg0.deepEquals(((FunctionOneArg)expr).m_arg0))
  			return false;
  	}
  	else if(null != ((FunctionOneArg)expr).m_arg0)
  		return false;

  	return true;
  }


}