import com.sun.org.apache.xalan.internal.xsltc.dom.SingletonIterator; //导入依赖的package包/类
/**
 * Implements the nodeset() extension function.
 */
public static DTMAxisIterator nodesetF(Object obj) {
    if (obj instanceof DOM) {
       //final DOMAdapter adapter = (DOMAdapter) obj;
       final DOM dom = (DOM)obj;
       return new SingletonIterator(dom.getDocument(), true);
    }
    else if (obj instanceof DTMAxisIterator) {
       return (DTMAxisIterator) obj;
    }
    else {
        final String className = obj.getClass().getName();
        runTimeError(DATA_CONVERSION_ERR, "node-set", className);
        return null;
    }
}
 

import com.sun.org.apache.xalan.internal.xsltc.dom.SingletonIterator; //导入依赖的package包/类
/**
 * Utility function: used to convert references to node-sets. If the
 * obj is an instanceof Node then create a singleton iterator.
 */
public static DTMAxisIterator referenceToNodeSet(Object obj) {
    // Convert var/param -> node
    if (obj instanceof Node) {
        return(new SingletonIterator(((Node)obj).node));
    }
    // Convert var/param -> node-set
    else if (obj instanceof DTMAxisIterator) {
        return(((DTMAxisIterator)obj).cloneIterator().reset());
    }
    else {
        final String className = obj.getClass().getName();
        runTimeError(DATA_CONVERSION_ERR, className, "node-set");
        return null;
    }
}
 

import com.sun.org.apache.xalan.internal.xsltc.dom.SingletonIterator; //导入依赖的package包/类
/**
 * Utility function: used with nth position filters to convert a sequence
 * of nodes to just one single node (the one at position n).
 */
public static DTMAxisIterator getSingleNode(DTMAxisIterator iterator) {
    int node = iterator.next();
    return(new SingletonIterator(node));
}