xpathparser.java

java1.6众多例子参考

    }
    else if (lookahead('(', 1) || (lookahead(':', 1) && lookahead('(', 3)))
    {
      matchFound = FunctionCall();
    }
    else
    {
      matchFound = false;
    }

    return matchFound;
  }

  /**
   *
   * Argument    ::=    Expr
   *
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected void Argument() throws javax.xml.transform.TransformerException
  {

    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH);

    appendOp(2, OpCodes.OP_ARGUMENT);
    Expr();

    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH,
      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos);
  }

  /**
   *
   * FunctionCall    ::=    FunctionName '(' ( Argument ( ',' Argument)*)? ')'
   *
   * @return true if, and only if, a FunctionCall was matched
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected boolean FunctionCall() throws javax.xml.transform.TransformerException
  {

    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH);

    if (lookahead(':', 1))
    {
      appendOp(4, OpCodes.OP_EXTFUNCTION);

      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 1, m_queueMark - 1);

      nextToken();
      consumeExpected(':');

      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 2, m_queueMark - 1);

      nextToken();
    }
    else
    {
      int funcTok = getFunctionToken(m_token);

      if (-1 == funcTok)
      {
        error(XPATHErrorResources.ER_COULDNOT_FIND_FUNCTION,
              new Object[]{ m_token });  //"Could not find function: "+m_token+"()");
      }

      switch (funcTok)
      {
      case OpCodes.NODETYPE_PI :
      case OpCodes.NODETYPE_COMMENT :
      case OpCodes.NODETYPE_TEXT :
      case OpCodes.NODETYPE_NODE :
        // Node type tests look like function calls, but they're not
        return false;
      default :
        appendOp(3, OpCodes.OP_FUNCTION);

        m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 1, funcTok);
      }

      nextToken();
    }

    consumeExpected('(');

    while (!tokenIs(')') && m_token != null)
    {
      if (tokenIs(','))
      {
        error(XPATHErrorResources.ER_FOUND_COMMA_BUT_NO_PRECEDING_ARG, null);  //"Found ',' but no preceding argument!");
      }

      Argument();

      if (!tokenIs(')'))
      {
        consumeExpected(',');

        if (tokenIs(')'))
        {
          error(XPATHErrorResources.ER_FOUND_COMMA_BUT_NO_FOLLOWING_ARG,
                null);  //"Found ',' but no following argument!");
        }
      }
    }

    consumeExpected(')');

    // Terminate for safety.
    m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ENDOP);
    m_ops.setOp(OpMap.MAPINDEX_LENGTH,m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1);
    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH, 
      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos);

    return true;
  }

  // ============= GRAMMAR FUNCTIONS =================

  /**
   *
   * LocationPath ::= RelativeLocationPath
   * | AbsoluteLocationPath
   *
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected void LocationPath() throws javax.xml.transform.TransformerException
  {

    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH);

    // int locationPathOpPos = opPos;
    appendOp(2, OpCodes.OP_LOCATIONPATH);

    boolean seenSlash = tokenIs('/');

    if (seenSlash)
    {
      appendOp(4, OpCodes.FROM_ROOT);

      // Tell how long the step is without the predicate
      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 2, 4);
      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 1, OpCodes.NODETYPE_ROOT);

      nextToken();
    } else if (m_token == null) {
      error(XPATHErrorResources.ER_EXPECTED_LOC_PATH_AT_END_EXPR, null);
    }

    if (m_token != null)
    {
      if (!RelativeLocationPath() && !seenSlash)
      {
        // Neither a '/' nor a RelativeLocationPath - i.e., matched nothing
        // "Location path expected, but found "+m_token+" was encountered."
        error(XPATHErrorResources.ER_EXPECTED_LOC_PATH, 
              new Object [] {m_token});
      }
    }

    // Terminate for safety.
    m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ENDOP);
    m_ops.setOp(OpMap.MAPINDEX_LENGTH,m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1);
    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH,
      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos);
  }

  /**
   *
   * RelativeLocationPath ::= Step
   * | RelativeLocationPath '/' Step
   * | AbbreviatedRelativeLocationPath
   *
   * @returns true if, and only if, a RelativeLocationPath was matched
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected boolean RelativeLocationPath()
               throws javax.xml.transform.TransformerException
  {
    if (!Step())
    {
      return false;
    }

    while (tokenIs('/'))
    {
      nextToken();

      if (!Step())
      {
        // RelativeLocationPath can't end with a trailing '/'
        // "Location step expected following '/' or '//'"
        error(XPATHErrorResources.ER_EXPECTED_LOC_STEP, null);
      }
    }

    return true;
  }

  /**
   *
   * Step    ::=    Basis Predicate
   * | AbbreviatedStep
   *
   * @returns false if step was empty (or only a '/'); true, otherwise
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected boolean Step() throws javax.xml.transform.TransformerException
  {
    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH);

    boolean doubleSlash = tokenIs('/');

    // At most a single '/' before each Step is consumed by caller; if the
    // first thing is a '/', that means we had '//' and the Step must not
    // be empty.
    if (doubleSlash)
    {
      nextToken();

      appendOp(2, OpCodes.FROM_DESCENDANTS_OR_SELF);

      // Have to fix up for patterns such as '//@foo' or '//attribute::foo',
      // which translate to 'descendant-or-self::node()/attribute::foo'.
      // notice I leave the '/' on the queue, so the next will be processed
      // by a regular step pattern.

      // Make room for telling how long the step is without the predicate
      m_ops.setOp(OpMap.MAPINDEX_LENGTH,m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1);
      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.NODETYPE_NODE);
      m_ops.setOp(OpMap.MAPINDEX_LENGTH,m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1);

      // Tell how long the step is without the predicate
      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 1,
          m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos);

      // Tell how long the step is with the predicate
      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH,
          m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos);

      opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH);
    }

    if (tokenIs("."))
    {
      nextToken();

      if (tokenIs('['))
      {
        error(XPATHErrorResources.ER_PREDICATE_ILLEGAL_SYNTAX, null);  //"'..[predicate]' or '.[predicate]' is illegal syntax.  Use 'self::node()[predicate]' instead.");
      }

      appendOp(4, OpCodes.FROM_SELF);

      // Tell how long the step is without the predicate
      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 2,4);
      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 1, OpCodes.NODETYPE_NODE);
    }
    else if (tokenIs(".."))
    {
      nextToken();
      appendOp(4, OpCodes.FROM_PARENT);

      // Tell how long the step is without the predicate
      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 2,4);
      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH) - 1, OpCodes.NODETYPE_NODE);
    }

    // There is probably a better way to test for this 
    // transition... but it gets real hairy if you try 
    // to do it in basis().
    else if (tokenIs('*') || tokenIs('@') || tokenIs('_')
             || (m_token!= null && Character.isLetter(m_token.charAt(0))))
    {
      Basis();

      while (tokenIs('['))
      {
        Predicate();
      }

      // Tell how long the entire step is.
      m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH,
        m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos); 
    }
    else
    {
      // No Step matched - that's an error if previous thing was a '//'
      if (doubleSlash)
      {
        // "Location step expected following '/' or '//'"
        error(XPATHErrorResources.ER_EXPECTED_LOC_STEP, null);
      }

      return false;
    }

    return true;
  }

  /**
   *
   * Basis    ::=    AxisName '::' NodeTest
   * | AbbreviatedBasis
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected void Basis() throws javax.xml.transform.TransformerException
  {

    int opPos = m_ops.getOp(OpMap.MAPINDEX_LENGTH);
    int axesType;

    // The next blocks guarantee that a FROM_XXX will be added.
    if (lookahead("::", 1))
    {
      axesType = AxisName();

      nextToken();
      nextToken();
    }
    else if (tokenIs('@'))
    {
      axesType = OpCodes.FROM_ATTRIBUTES;

      appendOp(2, axesType);
      nextToken();
    }
    else
    {
      axesType = OpCodes.FROM_CHILDREN;

      appendOp(2, axesType);
    }

    // Make room for telling how long the step is without the predicate
    m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1);

    NodeTest(axesType);

    // Tell how long the step is without the predicate
    m_ops.setOp(opPos + OpMap.MAPINDEX_LENGTH + 1,
      m_ops.getOp(OpMap.MAPINDEX_LENGTH) - opPos);
   }

  /**
   *
   * Basis    ::=    AxisName '::' NodeTest
   * | AbbreviatedBasis
   *
   * @return FROM_XXX axes type, found in {@link com.sun.org.apache.xpath.internal.compiler.Keywords}.
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected int AxisName() throws javax.xml.transform.TransformerException
  {

    Object val = Keywords.getAxisName(m_token);

    if (null == val)
    {
      error(XPATHErrorResources.ER_ILLEGAL_AXIS_NAME,
            new Object[]{ m_token });  //"illegal axis name: "+m_token);
    }

    int axesType = ((Integer) val).intValue();

    appendOp(2, axesType);

    return axesType;
  }

  /**
   *
   * NodeTest    ::=    WildcardName
   * | NodeType '(' ')'
   * | 'processing-instruction' '(' Literal ')'
   *
   * @param axesType FROM_XXX axes type, found in {@link com.sun.org.apache.xpath.internal.compiler.Keywords}.
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected void NodeTest(int axesType) throws javax.xml.transform.TransformerException
  {

    if (lookahead('(', 1))
    {
      Object nodeTestOp = Keywords.getNodeType(m_token);

      if (null == nodeTestOp)
      {
        error(XPATHErrorResources.ER_UNKNOWN_NODETYPE,
              new Object[]{ m_token });  //"Unknown nodetype: "+m_token);
      }
      else
      {
        nextToken();

        int nt = ((Integer) nodeTestOp).intValue();

        m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), nt);
        m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1);

        consumeExpected('(');

        if (OpCodes.NODETYPE_PI == nt)
        {
          if (!tokenIs(')'))
          {
            Literal();
          }
        }

        consumeExpected(')');
      }
    }
    else
    {

      // Assume name of attribute or element.
      m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.NODENAME);
      m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1);

      if (lookahead(':', 1))
      {
        if (tokenIs('*'))
        {
          m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ELEMWILDCARD);
        }
        else
        {
          m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), m_queueMark - 1);

          // Minimalist check for an NCName - just check first character
          // to distinguish from other possible tokens
          if (!Character.isLetter(m_tokenChar) && !tokenIs('_'))
          {
            // "Node test that matches either NCName:* or QName was expected."
            error(XPATHErrorResources.ER_EXPECTED_NODE_TEST, null);
          }
        }

        nextToken();
        consumeExpected(':');
      }
      else
      {
        m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.EMPTY);
      }

      m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1);

      if (tokenIs('*'))
      {
        m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), OpCodes.ELEMWILDCARD);
      }
      else
      {
        m_ops.setOp(m_ops.getOp(OpMap.MAPINDEX_LENGTH), m_queueMark - 1);

        // Minimalist check for an NCName - just check first character
        // to distinguish from other possible tokens
        if (!Character.isLetter(m_tokenChar) && !tokenIs('_'))
        {
          // "Node test that matches either NCName:* or QName was expected."
          error(XPATHErrorResources.ER_EXPECTED_NODE_TEST, null);
        }
      }

      m_ops.setOp(OpMap.MAPINDEX_LENGTH, m_ops.getOp(OpMap.MAPINDEX_LENGTH) + 1);

      nextToken();
    }
  }