code: /*
   * 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.
   */
  /*
   * $Id$
   */
  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.
   */
  public abstract class UnaryOperation extends Expression implements ExpressionOwner
  {
      static final long serialVersionUID = 6536083808424286166L;
  
    /** 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.
     * @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.
     *
     * @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.
     *
     *
     * @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.
     *
     *
     * @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.
     *
     *
     * @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;
  
    /** @return the operand of unary operation, as an Expression.
     */
    public Expression getOperand(){
      return m_right;
    }
    
    /**
     * @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 ExpressionOwner#getExpression()
     */
    public Expression getExpression()
    {
      return m_right;
    }
  
    /**
     * @see ExpressionOwner#setExpression(Expression)
     */
    public void setExpression(Expression exp)
    {
    	exp.exprSetParent(this);
    	m_right = exp;
    }
    
    /**
     * @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;
    }
  
  
  }
  