expr.java

来自「RESIN 3.2 最新源码」· Java 代码 · 共 690 行 · 第 1/2 页

    else if (obj instanceof NodeIterator)
      return (NodeIterator) obj;

    else if (obj instanceof ArrayList)
      return new NodeArrayListIterator(env, (ArrayList) obj);

    else {
      return new SingleNodeIterator(env, null);
    }
  }
  
  /**
   * Returns the object value of the node.
   *
   * @param node the node to evaluate and use as a context
   */
  public Object evalObject(Node node)
    throws XPathException
  {
    Env env = XPath.createEnv();
    env.setCurrentNode(node);
    env.setContextNode(node);

    Object result = evalObject(node, env);

    XPath.freeEnv(env);

    return result;
  }

  /**
   * Returns the object value of the node.
   *
   * @param node the node to evaluate and use as a context
   * @param env variable environment.
   */
  public abstract Object evalObject(Node node, ExprEnvironment env)
    throws XPathException;

  /**
   * Evaluates to a variable.
   *
   * @param node the node to evaluate and use as a context.
   * @param env the variable environment.
   *
   * @return a variable containing the value.
   */
  public Var evalVar(Node node, ExprEnvironment env)
    throws XPathException
  {
    Object obj = evalObject(node, env);

    return new ObjectVar(obj);
  }

  /**
   * Adds a variable with the expression's value.
   */
  public void addVar(Env newEnv, String name, Node node, Env env)
    throws XPathException
  {
    Var var = evalVar(node, env);

    newEnv.addVar(name, var);
  }

  /**
   * Sets a variable with the expression's value.
   */
  public void setVar(String name, Node node, Env env)
    throws XPathException
  {
    env.setVar(name, evalVar(node, env));
  }

  /**
   * Adds a param with the expression's value.
   */
  public void addParam(Env newEnv, String name,
                       Node node, Env env)
    throws XPathException
  {
    Var var = env.getVar(name);
      
    if (var == null)
      newEnv.addVar(name, evalVar(node, env));
    else
      newEnv.addVar(name, var);
  }

  /**
   * Convert a Java object to a boolean using the XPath rules.
   */
  public static boolean toBoolean(Object value)
    throws XPathException
  {
    if (value instanceof Node)
      value = XmlUtil.textValue((Node) value);
    else if (value instanceof NodeList) {
      NodeList list = (NodeList) value;

      return list.item(0) != null;
    }
    else if (value instanceof ArrayList) {
      ArrayList list = (ArrayList) value;
      return list.size() > 0;
    }
    else if (value instanceof Iterator) {
      return ((Iterator) value).hasNext();
    }

    if (value == null)
      return false;

    else if (value instanceof Double) {
      Double d = (Double) value;

      return d.doubleValue() != 0;
    }
    else if (value instanceof Boolean) {
      Boolean b = (Boolean) value;
      return b.booleanValue();
    }
    else if (value instanceof String) {
      String string = (String) value;
      return string != null && string.length() > 0;
    }
    else
      return true;
  }

  /**
   * Convert a Java object to a double using the XPath rules.
   */
  public static double toDouble(Object value)
    throws XPathException
  {
    if (value instanceof Node) {
      String string = XmlUtil.textValue((Node) value);

      if (string == null)
	return 0;
      else
	return stringToNumber(string);
    }
    else if (value instanceof NodeList) {
      NodeList list = (NodeList) value;

      value = list.item(0);
    }
    else if (value instanceof ArrayList) {
      ArrayList list = (ArrayList) value;
      if (list.size() > 0)
	value = list.get(0);
      else
	value = null;
    }
    else if (value instanceof NodeIterator) {
      value = ((NodeIterator) value).nextNode();
    }

    if (value instanceof Node)
      value = XmlUtil.textValue((Node) value);

    if (value == null)
      return 0;

    if (value instanceof Number) {
      Number d = (Number) value;

      return d.doubleValue();
    }
    else if (value instanceof Boolean) {
      Boolean b = (Boolean) value;
      return b.booleanValue() ? 1 : 0;
    }
    else if (value instanceof String) {
      return stringToNumber((String) value);
    }
    else
      return 0;
  }

  /**
   * Convert a Java object to a string using the XPath rules.
   */
  public static String toString(Object value)
    throws XPathException
  {
    if (value instanceof Node) {
      String s = XmlUtil.textValue((Node) value);

      if (s == null)
	return "";
      else
	return s;
    }
    else if (value instanceof NodeList) {
      NodeList list = (NodeList) value;

      value = list.item(0);
    }
    else if (value instanceof ArrayList) {
      ArrayList list = (ArrayList) value;
      if (list.size() > 0)
	value = list.get(0);
      else
	value = null;
    }
    else if (value instanceof Iterator) {
      value = ((Iterator) value).next();
    }

    if (value instanceof Node)
      value = XmlUtil.textValue((Node) value);
    else if (value instanceof Double) {
      double d = ((Double) value).doubleValue();

      if ((int) d == d)
	return String.valueOf((int) d);
      else
	return String.valueOf(d);
    }

    if (value == null)
      return "";
    else
      return value.toString();
  }

  /**
   * Convert a Java object to a node using the XPath rules.
   */
  public static Node toNode(Object value)
    throws XPathException
  {
    if (value instanceof Node)
      return (Node) value;
    else if (value instanceof NodeList) {
      NodeList list = (NodeList) value;
      value = list.item(0);
    }
    else if (value instanceof ArrayList) {
      ArrayList list = (ArrayList) value;
      if (list.size() > 0)
	value = list.get(0);
      else
	value = null;
    }
    else if (value instanceof NodeIterator) {
      value = ((NodeIterator) value).nextNode();
    }

    if (value instanceof Node)
      return (Node) value;
    else
      return null;
  }

  /**
   * Convert a string to a double following XPath.
   *
   * @param string string to be treated as a double.
   * @return the double value.
   */
  static protected double stringToNumber(String string)
    throws XPathException
  {
    int i = 0;
    int length = string.length();
    boolean isNumber = false;
    for (; i < length && XmlChar.isWhitespace(string.charAt(i)); i++) {
    }

    if (i >= length)
      return 0;

    int ch = string.charAt(i);;
    int sign = 1;
    if (ch == '-') {
      sign = -1;
      for (i++; i < length && XmlChar.isWhitespace(string.charAt(i)); i++) {
      }
    }
      
    double value = 0;
    double exp = 1;
    for (; i < length && (ch = string.charAt(i)) >= '0' && ch <= '9'; i++) {
      value = 10 * value + ch - '0';
      isNumber = true;
    }

    if (ch == '.') {
      for (i++;
	   i < length && (ch = string.charAt(i)) >= '0' && ch <= '9';
	   i++) {
	value = 10 * value + ch - '0';
	isNumber = true;
	exp = 10 * exp;
      }
    }

    double pexp = 1.0;
    if (ch == 'e' || ch == 'E') {
      int eSign = 1;
      i++;

      if (i >= length)
        return Double.NaN;

      if (string.charAt(i) == '-') {
        eSign = -1;
        i++;
      }
      else if (string.charAt(i) == '+') {
        i++;
      }

      int v = 0;
      for (; i < length && (ch = string.charAt(i)) >= '0' && ch <= '9'; i++) {
        v = v * 10 + ch - '0';
      }

      pexp = Math.pow(10, eSign * v);
    }

    for (; i < length && XmlChar.isWhitespace(string.charAt(i)); i++) {
    }

    if (i < length || ! isNumber)
      return Double.NaN;
    else
      return sign * value * pexp / exp;
  }

  /**
   * Convert from an expression to a pattern.
   */
  protected AbstractPattern toNodeList()
  {
    return new FromExpr(null, this);
  }
}