import com.sun.org.apache.xml.internal.dtm.ref.EmptyIterator; //导入依赖的package包/类
/**
 * Interprets the arguments passed from the document() function (see
 * com/sun/org/apache/xalan/internal/xsltc/compiler/DocumentCall.java) and returns an
 * iterator containing the requested nodes. Builds a union-iterator if
 * several documents are requested.
 * 2 arguments arg1 and arg2.  document(Obj, node-set) call
 */
public static DTMAxisIterator documentF(Object arg1, DTMAxisIterator arg2,
                        String xslURI, AbstractTranslet translet, DOM dom)
throws TransletException {
    String baseURI = null;
    final int arg2FirstNode = arg2.next();
    if (arg2FirstNode == DTMAxisIterator.END) {
        //  the second argument node-set is empty
        return EmptyIterator.getInstance();
    } else {
        //System.err.println("arg2FirstNode name: "
        //                   + dom.getNodeName(arg2FirstNode )+"["
        //                   +Integer.toHexString(arg2FirstNode )+"]");
        baseURI = dom.getDocumentURI(arg2FirstNode);
        if (!SystemIDResolver.isAbsoluteURI(baseURI))
           baseURI = SystemIDResolver.getAbsoluteURIFromRelative(baseURI);
    }

    try {
        if (arg1 instanceof String) {
            if (((String)arg1).length() == 0) {
                return document(xslURI, "", translet, dom);
            } else {
                return document((String)arg1, baseURI, translet, dom);
            }
        } else if (arg1 instanceof DTMAxisIterator) {
            return document((DTMAxisIterator)arg1, baseURI, translet, dom);
        } else {
            final String err = "document("+arg1.toString()+")";
            throw new IllegalArgumentException(err);
        }
    } catch (Exception e) {
        throw new TransletException(e);
    }
}