src/org/apache/xpath/VariableComposeState.java

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package org.apache.xpath;

import org.apache.xml.utils.QName;

/**
 * This is a rather low lever interface that is passed to the 
 * fixupVariables method on expressions.
 * 
 * Created Jul 19, 2002
 * @author sboag
 */
public interface VariableComposeState
{
  /**
   * Given a qualified name, return an integer ID that can be 
   * quickly compared.
   *
   * @param qname a qualified name object, must not be null.
   *
   * @return the expanded-name id of the qualified name.
   */
  public int getQNameID(QName qname);

  /**
   * Add the name of a qualified name within the template.  The position in 
   * the vector is its ID.
   * @param qname A qualified name of a param or variable, should be non-null.
   * @return the index where the variable was added.
   */
  int addVariableName(final org.apache.xml.utils.QName qname);

  /**
   * Reset the stack frame size to zero.
   */
  void resetStackFrameSize();

  /**
   * Get the current size of the stack frame.
   * @return int The size of the stack frame.
   */
  int getFrameSize();

  /**
   * Get the current size of the stack frame.  Use this to record the position 
   * in a template element at startElement, so that it can be popped 
   * at endElement.
   */
  int getCurrentStackFrameSize();

  /**
   * Set the current size of the stack frame.
   */
  void setCurrentStackFrameSize(int sz);

  /**
   * Get the size of the globals area.
   * @return int
   */
  int getGlobalsSize();

  /**
   * Push a "mark" on the stack that will delimit a scope.
   */
  void pushStackMark();

  /**
   * Pop the variable scope to the last mark pushed.
   */
  void popStackMark();

  /**
   * Get the a 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).
   * 
   * @return A reference to the vector of variable names.  The reference 
   * returned is owned by the implementor of this interface, 
   * and so should not really be mutated, or stored anywhere.
   */
  java.util.Vector getVariableNames();

}