Java XObject.CLASS_NODESET属性代码示例

/**
   * Given an XObject, determine the corresponding DOM XPath type
   *
   * @return type string
   */
  private short getTypeFromXObject(XObject object) {
      switch (object.getType()) {
        case XObject.CLASS_BOOLEAN: return BOOLEAN_TYPE;
        case XObject.CLASS_NODESET: return UNORDERED_NODE_ITERATOR_TYPE;
        case XObject.CLASS_NUMBER: return NUMBER_TYPE;
        case XObject.CLASS_STRING: return STRING_TYPE;
        // XPath 2.0 types
//          case XObject.CLASS_DATE:
//          case XObject.CLASS_DATETIME:
//          case XObject.CLASS_DTDURATION:
//          case XObject.CLASS_GDAY:
//          case XObject.CLASS_GMONTH:
//          case XObject.CLASS_GMONTHDAY:
//          case XObject.CLASS_GYEAR:
//          case XObject.CLASS_GYEARMONTH:
//          case XObject.CLASS_TIME:
//          case XObject.CLASS_YMDURATION: return STRING_TYPE; // treat all date types as strings?

        case XObject.CLASS_RTREEFRAG: return UNORDERED_NODE_ITERATOR_TYPE;
        case XObject.CLASS_NULL: return ANY_TYPE; // throw exception ?
        default: return ANY_TYPE; // throw exception ?
    }

  }
 

/**
 * Construct an XPathExpressionResult object based on the result of the
 * evaluation and cast to the specified class type.
 * @param <T> The class type
 * @param resultObject the result of an evaluation
 * @param type The class type expected to be returned by the XPath expression.
 * @return an instance of the specified type or null if the XObject returned
 * an UNKNOWN object type.
 * @throws TransformerException if there is an error converting the result
 * to the specified type. It's unlikely to happen. This is mostly needed
 * by the internal XPath engine.
 */
<T> T getXPathResult(XObject resultObject, Class<T> type)
        throws TransformerException {
    int resultType = resultObject.getType();

    switch (resultType) {
        case XObject.CLASS_BOOLEAN :
            return type.cast(new XPathResultImpl<>(resultObject, Boolean.class));
        case XObject.CLASS_NUMBER :
            return type.cast(new XPathResultImpl<>(resultObject, Double.class));
        case XObject.CLASS_STRING :
            return type.cast(new XPathResultImpl<>(resultObject, String.class));
        case XObject.CLASS_NODESET :
            return type.cast(new XPathResultImpl<>(resultObject, XPathNodes.class));
        case XObject.CLASS_RTREEFRAG :  //NODE
            return type.cast(new XPathResultImpl<>(resultObject, Node.class));
    }

    return null;
}
 

/**
 * Read the XObject and set values in accordance with the result type
 * @param resultObject  internal XPath result object
 * @throws TransformerException  if there is an error reading the XPath
 * result.
 */
private void getResult(XObject resultObject) throws TransformerException {
    switch (resultType) {
        case XObject.CLASS_BOOLEAN:
            boolValue = resultObject.bool();
            mapToType = XPathResultType.BOOLEAN;
            break;
        case XObject.CLASS_NUMBER:
            numValue = resultObject.num();
            mapToType = XPathResultType.NUMBER;
            break;
        case XObject.CLASS_STRING:
            strValue = resultObject.str();
            mapToType = XPathResultType.STRING;
            break;
        case XObject.CLASS_NODESET:
            mapToType = XPathResultType.NODESET;
            nodeList = resultObject.nodelist();
            break;
        case XObject.CLASS_RTREEFRAG:  //NODE
            mapToType = XPathResultType.NODE;
            NodeIterator ni = resultObject.nodeset();
            //Return the first node, or null
            node = ni.nextNode();
            break;
    }
}
 

/**
 * Read the internal result object and return the value in accordance with
 * the type specified.
 *
 * @param <T> The expected class type.
 * @param resultObject internal XPath result object
 * @param type the class type
 * @return The value of the result, null in case of unexpected type.
 * @throws TransformerException  if there is an error reading the XPath
 * result.
 */
static <T> T getValue(XObject resultObject, Class<T> type) throws TransformerException {
    Objects.requireNonNull(type);
    if (type.isAssignableFrom(XPathEvaluationResult.class)) {
        return type.cast(new XPathResultImpl<T>(resultObject, type));
    }
    int resultType = classToInternalType(type);
    switch (resultType) {
        case XObject.CLASS_BOOLEAN:
            return type.cast(resultObject.bool());
        case XObject.CLASS_NUMBER:
            if (Double.class.isAssignableFrom(type)) {
                return type.cast(resultObject.num());
            } else if (Integer.class.isAssignableFrom(type)) {
                return type.cast((int)resultObject.num());
            } else if (Long.class.isAssignableFrom(type)) {
                return type.cast((long)resultObject.num());
            }
            /*
              This is to suppress warnings. By the current specification,
            among numeric types, only Double, Integer and Long are supported.
            */
            break;
        case XObject.CLASS_STRING:
            return type.cast(resultObject.str());
        case XObject.CLASS_NODESET:
            XPathNodes nodeSet = new XPathNodesImpl(resultObject.nodelist(),
                    Node.class);
            return type.cast(nodeSet);
        case XObject.CLASS_RTREEFRAG:  //NODE
            NodeIterator ni = resultObject.nodeset();
            //Return the first node, or null
            return type.cast(ni.nextNode());
    }

    return null;
}
 

/**
 * Map the specified class type to the internal result type
 *
 * @param <T> The expected class type.
 * @param type the class type
 * @return the internal XObject type.
 */
static <T> int classToInternalType(Class<T> type) {
    if (type.isAssignableFrom(Boolean.class)) {
        return XObject.CLASS_BOOLEAN;
    } else if (Number.class.isAssignableFrom(type)) {
        return XObject.CLASS_NUMBER;
    } else if (type.isAssignableFrom(String.class)) {
        return XObject.CLASS_STRING;
    } else if (type.isAssignableFrom(XPathNodes.class)) {
        return XObject.CLASS_NODESET;
    } else if (type.isAssignableFrom(Node.class)) {
        return XObject.CLASS_RTREEFRAG;
    }
    return XObject.CLASS_NULL;
}