/*
 * 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: UnaryOperation.java 468655 2006-10-28 07:12:06Z minchau $
 */
package org.apache.xpath.operations;

import org.apache.xpath.Expression;
import org.apache.xpath.ExpressionOwner;
import org.apache.xpath.XPathContext;
import org.apache.xpath.XPathVisitor;
import org.apache.xpath.objects.XObject;

The unary operation base class.
/**
 * The unary operation base class.
 */
public abstract class UnaryOperation extends Expression implements ExpressionOwner
{
    static final long serialVersionUID = 6536083808424286166L;

  
The operand for the operation.
 @serial /** The operand for the operation.
   *  @serial */
  protected Expression m_right;
  
  
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)
  {
    m_right.fixupVariables(vars, globalsSize);
  }
  
  
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()
  {

    if (null != m_right && m_right.canTraverseOutsideSubtree())
      return true;

    return false;
  }

  
Set the expression operand for the operation.
Params:
r – The expression operand to which the unary operation will be 
         applied./**
   * Set the expression operand for the operation.
   *
   *
   * @param r The expression operand to which the unary operation will be 
   *          applied.
   */
  public void setRight(Expression r)
  {
    m_right = r;
    r.exprSetParent(this);
  }

  
Execute the operand and apply the unary operation to the result.
Params:
xctxt – The runtime execution context.
Throws:
TransformerException – 
Returns:
An XObject that represents the result of applying the unary 
        operation to the evaluated operand./**
   * Execute the operand and apply the unary operation to the result.
   *
   *
   * @param xctxt The runtime execution context.
   *
   * @return An XObject that represents the result of applying the unary 
   *         operation to the evaluated operand.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
  {

    return operate(m_right.execute(xctxt));
  }

  
Apply the operation to two operands, and return the result.
Params:
right – non-null reference to the evaluated right operand.
Throws:
TransformerException – 
Returns:
non-null reference to the XObject that represents the result of the operation./**
   * Apply the operation to two operands, and return the result.
   *
   *
   * @param right non-null reference to the evaluated right operand.
   *
   * @return non-null reference to the XObject that represents the result of the operation.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public abstract XObject operate(XObject right)
    throws javax.xml.transform.TransformerException;

  
Returns:
the operand of unary operation, as an Expression./** @return the operand of unary operation, as an Expression.
   */
  public Expression getOperand(){
    return m_right;
  }
  
  
See Also:
callVisitors.callVisitors(ExpressionOwner, XPathVisitor)/**
   * @see org.apache.xpath.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)
   */
  public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)
  {
  	if(visitor.visitUnaryOperation(owner, this))
  	{
  		m_right.callVisitors(this, visitor);
  	}
  }


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

  
See Also:
setExpression.setExpression(Expression)/**
   * @see ExpressionOwner#setExpression(Expression)
   */
  public void setExpression(Expression exp)
  {
  	exp.exprSetParent(this);
  	m_right = exp;
  }
  
  
See Also:
deepEquals.deepEquals(Expression)/**
   * @see Expression#deepEquals(Expression)
   */
  public boolean deepEquals(Expression expr)
  {
  	if(!isSameClass(expr))
  		return false;
  		
  	if(!m_right.deepEquals(((UnaryOperation)expr).m_right))
  		return false;
  		
  	return true;
  }


}