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.xalan.templates;
  
  import org.apache.xml.utils.FastStringBuffer;
  import org.apache.xpath.XPathContext;
  
  /**
   * Class to hold a part, either a string or XPath,
   * of an Attribute Value Template.
   * @xsl.usage internal
   */
  public abstract class AVTPart implements java.io.Serializable, XSLTVisitable
  {
      static final long serialVersionUID = -1747749903613916025L;
  
    /**
     * Construct a part.
     */
    public AVTPart(){}
  
    /**
     * Get the AVT part as the original string.
     *
     * @return the AVT part as the original string.
     */
    public abstract String getSimpleString();
  
    /**
     * Write the evaluated value into the given
     * string buffer.
     *
     * @param xctxt The XPath context to use to evaluate this AVT.
     * @param buf Buffer to write into.
     * @param context The current source tree context.
     * @param nsNode The current namespace context (stylesheet tree context).
     *
     * @throws javax.xml.transform.TransformerException
     */
    public abstract void evaluate(
      XPathContext xctxt, FastStringBuffer buf, int context,
        org.apache.xml.utils.PrefixResolver nsNode)
          throws javax.xml.transform.TransformerException;
  
    /**
     * Set the XPath support.
     *
     * @param support XPathContext to set. 
     */
    public void setXPathSupport(XPathContext support){}
    
    /**
     * 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 false;
     }
     
    /**
     * 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 abstract void fixupVariables(java.util.Vector vars, int globalsSize);
  
  
  }
  