compiler.java

java1.6众多例子参考

   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.operations.Quo} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
//  protected Expression quo(int opPos) throws TransformerException
//  {
//    return compileOperation(new Quo(), opPos);
//  }

  /**
   * Compile a unary '-' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.operations.Neg} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression neg(int opPos) throws TransformerException
  {
    return compileUnary(new Neg(), opPos);
  }

  /**
   * Compile a 'string(...)' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.operations.String} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression string(int opPos) throws TransformerException
  {
    return compileUnary(new com.sun.org.apache.xpath.internal.operations.String(), opPos);
  }

  /**
   * Compile a 'boolean(...)' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.operations.Bool} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression bool(int opPos) throws TransformerException
  {
    return compileUnary(new com.sun.org.apache.xpath.internal.operations.Bool(), opPos);
  }

  /**
   * Compile a 'number(...)' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.operations.Number} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression number(int opPos) throws TransformerException
  {
    return compileUnary(new com.sun.org.apache.xpath.internal.operations.Number(), opPos);
  }

  /**
   * Compile a literal string value.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.objects.XString} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression literal(int opPos)
  {

    opPos = getFirstChildPos(opPos);

    return (XString) getTokenQueue().elementAt(getOp(opPos));
  }

  /**
   * Compile a literal number value.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.objects.XNumber} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression numberlit(int opPos)
  {

    opPos = getFirstChildPos(opPos);

    return (XNumber) getTokenQueue().elementAt(getOp(opPos));
  }

  /**
   * Compile a variable reference.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.operations.Variable} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression variable(int opPos) throws TransformerException
  {

    Variable var = new Variable();

    opPos = getFirstChildPos(opPos);

    int nsPos = getOp(opPos);
    java.lang.String namespace 
      = (OpCodes.EMPTY == nsPos) ? null 
                                   : (java.lang.String) getTokenQueue().elementAt(nsPos);
    java.lang.String localname 
      = (java.lang.String) getTokenQueue().elementAt(getOp(opPos+1));
    QName qname = new QName(namespace, localname);

    var.setQName(qname);

    return var;
  }

  /**
   * Compile an expression group.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to the contained expression.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression group(int opPos) throws TransformerException
  {

    // no-op
    return compile(opPos + 2);
  }

  /**
   * Compile a function argument.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to the argument expression.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression arg(int opPos) throws TransformerException
  {

    // no-op
    return compile(opPos + 2);
  }

  /**
   * Compile a location path union. The UnionPathIterator itself may create
   * {@link com.sun.org.apache.xpath.internal.axes.LocPathIterator} children.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.axes.LocPathIterator} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression union(int opPos) throws TransformerException
  {
    locPathDepth++;
    try
    {
      return UnionPathIterator.createUnionIterator(this, opPos);
    }
    finally
    {
      locPathDepth--;
    }
  }
  
  private int locPathDepth = -1;
  
  /**
   * Get the level of the location path or union being constructed.  
   * @return 0 if it is a top-level path.
   */
  public int getLocationPathDepth()
  {
    return locPathDepth;
  }

  /**
   * Get the function table  
   */
  FunctionTable getFunctionTable()
  {
    return m_functionTable;
  }

  /**
   * Compile a location path.  The LocPathIterator itself may create
   * {@link com.sun.org.apache.xpath.internal.axes.AxesWalker} children.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.axes.LocPathIterator} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  public Expression locationPath(int opPos) throws TransformerException
  {
    locPathDepth++;
    try
    {
      DTMIterator iter = WalkerFactory.newDTMIterator(this, opPos, (locPathDepth == 0));
      return (Expression)iter; // cast OK, I guess.
    }
    finally
    {
      locPathDepth--;
    }
  }

  /**
   * Compile a location step predicate expression.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return the contained predicate expression.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  public Expression predicate(int opPos) throws TransformerException
  {
    return compile(opPos + 2);
  }

  /**
   * Compile an entire match pattern expression.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.patterns.UnionPattern} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression matchPattern(int opPos) throws TransformerException
  {
    locPathDepth++;
    try
    {
      // First, count...
      int nextOpPos = opPos;
      int i;

      for (i = 0; getOp(nextOpPos) == OpCodes.OP_LOCATIONPATHPATTERN; i++)
      {
        nextOpPos = getNextOpPos(nextOpPos);
      }

      if (i == 1)
        return compile(opPos);

      UnionPattern up = new UnionPattern();
      StepPattern[] patterns = new StepPattern[i];

      for (i = 0; getOp(opPos) == OpCodes.OP_LOCATIONPATHPATTERN; i++)
      {
        nextOpPos = getNextOpPos(opPos);
        patterns[i] = (StepPattern) compile(opPos);
        opPos = nextOpPos;
      }

      up.setPatterns(patterns);

      return up;
    }
    finally
    {
      locPathDepth--;
    }
  }

  /**
   * Compile a location match pattern unit expression.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.patterns.StepPattern} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  public Expression locationPathPattern(int opPos)
          throws TransformerException
  {

    opPos = getFirstChildPos(opPos);

    return stepPattern(opPos, 0, null);
  }

  /**
   * Get a {@link org.w3c.dom.traversal.NodeFilter} bit set that tells what 
   * to show for a given node test.
   *
   * @param opPos the op map position for the location step.
   *
   * @return {@link org.w3c.dom.traversal.NodeFilter} bit set that tells what 
   *         to show for a given node test.
   */
  public int getWhatToShow(int opPos)
  {

    int axesType = getOp(opPos);
    int testType = getOp(opPos + 3);

    // System.out.println("testType: "+testType);
    switch (testType)
    {
    case OpCodes.NODETYPE_COMMENT :
      return DTMFilter.SHOW_COMMENT;
    case OpCodes.NODETYPE_TEXT :
//      return DTMFilter.SHOW_TEXT | DTMFilter.SHOW_COMMENT;
      return DTMFilter.SHOW_TEXT | DTMFilter.SHOW_CDATA_SECTION ;
    case OpCodes.NODETYPE_PI :
      return DTMFilter.SHOW_PROCESSING_INSTRUCTION;
    case OpCodes.NODETYPE_NODE :
//      return DTMFilter.SHOW_ALL;
      switch (axesType)
      {
      case OpCodes.FROM_NAMESPACE:
        return DTMFilter.SHOW_NAMESPACE;
      case OpCodes.FROM_ATTRIBUTES :
      case OpCodes.MATCH_ATTRIBUTE :
        return DTMFilter.SHOW_ATTRIBUTE;
      case OpCodes.FROM_SELF:
      case OpCodes.FROM_ANCESTORS_OR_SELF:
      case OpCodes.FROM_DESCENDANTS_OR_SELF:
        return DTMFilter.SHOW_ALL;
      default:
        if (getOp(0) == OpCodes.OP_MATCHPATTERN)
          return ~DTMFilter.SHOW_ATTRIBUTE
                  & ~DTMFilter.SHOW_DOCUMENT
                  & ~DTMFilter.SHOW_DOCUMENT_FRAGMENT;
        else
          return ~DTMFilter.SHOW_ATTRIBUTE;
      }
    case OpCodes.NODETYPE_ROOT :
      return DTMFilter.SHOW_DOCUMENT | DTMFilter.SHOW_DOCUMENT_FRAGMENT;
    case OpCodes.NODETYPE_FUNCTEST :
      return NodeTest.SHOW_BYFUNCTION;
    case OpCodes.NODENAME :
      switch (axesType)
      {
      case OpCodes.FROM_NAMESPACE :
        return DTMFilter.SHOW_NAMESPACE;
      case OpCodes.FROM_ATTRIBUTES :
      case OpCodes.MATCH_ATTRIBUTE :
        return DTMFilter.SHOW_ATTRIBUTE;

      // break;
      case OpCodes.MATCH_ANY_ANCESTOR :
      case OpCodes.MATCH_IMMEDIATE_ANCESTOR :
        return DTMFilter.SHOW_ELEMENT;

      // break;
      default :
        return DTMFilter.SHOW_ELEMENT;
      }
    default :
      // System.err.println("We should never reach here.");
      return DTMFilter.SHOW_ALL;
    }
  }
  
private static final boolean DEBUG = false;

  /**
   * Compile a step pattern unit expression, used for both location paths 
   * and match patterns.
   * 
   * @param opPos The current position in the m_opMap array.
   * @param stepCount The number of steps to expect.
   * @param ancestorPattern The owning StepPattern, which may be null.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.patterns.StepPattern} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected StepPattern stepPattern(
          int opPos, int stepCount, StepPattern ancestorPattern)
            throws TransformerException
  {

    int startOpPos = opPos;
    int stepType = getOp(opPos);

    if (OpCodes.ENDOP == stepType)
    {
      return null;
    }
    
    boolean addMagicSelf = true;

    int endStep = getNextOpPos(opPos);

    // int nextStepType = getOpMap()[endStep];
    StepPattern pattern;
    
    // boolean isSimple = ((OpCodes.ENDOP == nextStepType) && (stepCount == 0));
    int argLen;

    switch (stepType)
    {
    case OpCodes.OP_FUNCTION :
      if(DEBUG)
        System.out.println("MATCH_FUNCTION: "+m_currentPattern);