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 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.sun.xml.internal.ws.streaming;

import com.sun.istack.internal.FinalArrayList;
import com.sun.istack.internal.NotNull;
import com.sun.istack.internal.XMLStreamException2;
import com.sun.xml.internal.ws.util.xml.DummyLocation;
import com.sun.xml.internal.ws.util.xml.XmlUtil;
import org.w3c.dom.Attr;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import static org.w3c.dom.Node.*;
import org.w3c.dom.NodeList;
import org.w3c.dom.ProcessingInstruction;
import org.w3c.dom.Text;

import javax.xml.namespace.NamespaceContext;
import javax.xml.namespace.QName;
import javax.xml.stream.Location;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.util.Collections;
import java.util.Iterator;

Create an XMLStreamReader on top of a DOM tree. 

Since various libraries as well as users often create "incorrect" DOM node,
this class spends a lot of efforts making sure that broken DOM trees are
nevertheless interpreted correctly.
 For example, if a DOM level 1 tree is passed, each method will attempt to return the correct value by using Node.getNodeName(). 

Similarly, if DOM is missing explicit namespace declarations,
this class attempts to emulate necessary declarations.
Author:
Santiago.PericasGeertsen@sun.com, Kohsuke Kawaguchi/**
 * Create an {@link XMLStreamReader} on top of a DOM tree.
 *
 * <p>
 * Since various libraries as well as users often create "incorrect" DOM node,
 * this class spends a lot of efforts making sure that broken DOM trees are
 * nevertheless interpreted correctly.
 *
 * <p>
 * For example, if a DOM level
 * 1 tree is passed, each method will attempt to return the correct value
 * by using {@link Node#getNodeName()}.
 *
 * <p>
 * Similarly, if DOM is missing explicit namespace declarations,
 * this class attempts to emulate necessary declarations.
 *
 *
 * @author Santiago.PericasGeertsen@sun.com
 * @author Kohsuke Kawaguchi
 */
public class DOMStreamReader implements XMLStreamReader, NamespaceContext {

    
Current DOM node being traversed.
/**
     * Current DOM node being traversed.
     */
    protected Node _current;

    
Starting node of the subtree being traversed.
/**
     * Starting node of the subtree being traversed.
     */
    private Node _start;

    
Named mapping for attributes and NS decls for the current node.
/**
     * Named mapping for attributes and NS decls for the current node.
     */
    private NamedNodeMap _namedNodeMap;

    
If the reader points at the text node, its whole value. 
 This is simply a cache of Text.getWholeText() of _current, but when a large binary data sent as base64 text, this could get very much non-trivial. /**
     * If the reader points at {@link #CHARACTERS the text node},
     * its whole value.
     *
     * <p>
     * This is simply a cache of {@link Text#getWholeText()} of {@link #_current},
     * but when a large binary data sent as base64 text, this could get very much
     * non-trivial.
     */
    protected String wholeText;

    
List of attributes extracted from _namedNodeMap.
/**
     * List of attributes extracted from <code>_namedNodeMap</code>.
     */
    private final FinalArrayList<Attr> _currentAttributes = new FinalArrayList<Attr>();

    
Scope buffer. /**
     * {@link Scope} buffer.
     */
    protected Scope[] scopes = new Scope[8];

    
Depth of the current element. The first element gets depth==0. Also used as the index to scopes. /**
     * Depth of the current element. The first element gets depth==0.
     * Also used as the index to {@link #scopes}.
     */
    protected int depth = 0;

    
State of this reader. Any of the valid states defined in StAX'
XMLStreamConstants class.
/**
     * State of this reader. Any of the valid states defined in StAX'
     * XMLStreamConstants class.
     */
    protected int _state;

    
Namespace declarations on one element.
Instances are reused.
/**
     * Namespace declarations on one element.
     *
     * Instances are reused.
     */
    protected static final class Scope {
        
Scope for the parent element.
/**
         * Scope for the parent element.
         */
        final Scope parent;

        
List of namespace declarations extracted from _namedNodeMap
/**
         * List of namespace declarations extracted from <code>_namedNodeMap</code>
         */
        final FinalArrayList<Attr> currentNamespaces = new FinalArrayList<Attr>();

        
Additional namespace declarations obtained as a result of "fixing" DOM tree,
which were not part of the original DOM tree.
One entry occupies two spaces (prefix followed by URI.)
/**
         * Additional namespace declarations obtained as a result of "fixing" DOM tree,
         * which were not part of the original DOM tree.
         *
         * One entry occupies two spaces (prefix followed by URI.)
         */
        final FinalArrayList<String> additionalNamespaces = new FinalArrayList<String>();

        Scope(Scope parent) {
            this.parent = parent;
        }

        void reset() {
            currentNamespaces.clear();
            additionalNamespaces.clear();
        }

        int getNamespaceCount() {
            return currentNamespaces.size()+additionalNamespaces.size()/2;
        }

        String getNamespacePrefix(int index) {
            int sz = currentNamespaces.size();
            if(index< sz) {
                Attr attr = currentNamespaces.get(index);
                String result = attr.getLocalName();
                if (result == null) {
                    result = QName.valueOf(attr.getNodeName()).getLocalPart();
                }
                return result.equals("xmlns") ? null : result;
            } else {
                return additionalNamespaces.get((index-sz)*2);
            }
        }

        String getNamespaceURI(int index) {
            int sz = currentNamespaces.size();
            if(index< sz) {
                return currentNamespaces.get(index).getValue();
            } else {
                return additionalNamespaces.get((index-sz)*2+1);
            }
        }

        
Returns the prefix bound to the given URI, or null.
This method recurses to the parent.
/**
         * Returns the prefix bound to the given URI, or null.
         * This method recurses to the parent.
         */
        String getPrefix(String nsUri) {
            for( Scope sp=this; sp!=null; sp=sp.parent ) {
                for( int i=sp.currentNamespaces.size()-1; i>=0; i--) {
                    String result = getPrefixForAttr(sp.currentNamespaces.get(i),nsUri);
                    if(result!=null)
                        return result;
                }
                for( int i=sp.additionalNamespaces.size()-2; i>=0; i-=2 )
                    if(sp.additionalNamespaces.get(i+1).equals(nsUri))
                        return sp.additionalNamespaces.get(i);
            }
            return null;
        }

        
Returns the namespace URI bound by the given prefix.
Params:
prefix – 
     Prefix to look up./**
         * Returns the namespace URI bound by the given prefix.
         *
         * @param prefix
         *      Prefix to look up.
         */
        String getNamespaceURI(@NotNull String prefix) {
            String nsDeclName = prefix.length()==0 ? "xmlns" : "xmlns:"+prefix;

            for( Scope sp=this; sp!=null; sp=sp.parent ) {
                for( int i=sp.currentNamespaces.size()-1; i>=0; i--) {
                    Attr a = sp.currentNamespaces.get(i);
                    if(a.getNodeName().equals(nsDeclName))
                        return a.getValue();
                }
                for( int i=sp.additionalNamespaces.size()-2; i>=0; i-=2 )
                    if(sp.additionalNamespaces.get(i).equals(prefix))
                        return sp.additionalNamespaces.get(i+1);
            }
            return null;
        }
    }


    public DOMStreamReader() {
    }

    public DOMStreamReader(Node node) {
        setCurrentNode(node);
    }

    public void setCurrentNode(Node node) {
        scopes[0] = new Scope(null);
        depth=0;

        _start = _current = node;
        _state = START_DOCUMENT;
        // verifyDOMIntegrity(node);
        // displayDOM(node, System.out);
    }

    public void close() throws XMLStreamException {
    }

    
Called when the current node is Element to look at attribute list (which contains both ns decl and attributes in DOM) and split them to attributes-proper and namespace decls. /**
     * Called when the current node is {@link Element} to look at attribute list
     * (which contains both ns decl and attributes in DOM) and split them
     * to attributes-proper and namespace decls.
     */
    protected void splitAttributes() {
        // Clear attribute and namespace lists
        _currentAttributes.clear();

        Scope scope = allocateScope();

        _namedNodeMap = _current.getAttributes();
        if (_namedNodeMap != null) {
            final int n = _namedNodeMap.getLength();
            for (int i = 0; i < n; i++) {
                final Attr attr = (Attr) _namedNodeMap.item(i);
                final String attrName = attr.getNodeName();
                if (attrName.startsWith("xmlns:") || attrName.equals("xmlns")) {     // NS decl?
                    scope.currentNamespaces.add(attr);
                }
                else {
                    _currentAttributes.add(attr);
                }
            }
        }

        // verify that all the namespaces used in element and attributes are indeed available
        ensureNs(_current);
        for( int i=_currentAttributes.size()-1; i>=0; i-- ) {
            Attr a = _currentAttributes.get(i);
            if(fixNull(a.getNamespaceURI()).length()>0)
                ensureNs(a);    // no need to declare "" for attributes in the default namespace
        }
    }

    
Sub-routine of splitAttributes(). 

Makes sure that the namespace URI/prefix used in the given node is available,
and if not, declare it on the current scope to "fix" it.
It's often common to create DOM trees without putting namespace declarations,
and this makes sure that such DOM tree will be properly marshalled.
/**
     * Sub-routine of {@link #splitAttributes()}.
     *
     * <p>
     * Makes sure that the namespace URI/prefix used in the given node is available,
     * and if not, declare it on the current scope to "fix" it.
     *
     * It's often common to create DOM trees without putting namespace declarations,
     * and this makes sure that such DOM tree will be properly marshalled.
     */
    private void ensureNs(Node n) {
        String prefix = fixNull(n.getPrefix());
        String uri = fixNull(n.getNamespaceURI());

        Scope scope = scopes[depth];

        String currentUri = scope.getNamespaceURI(prefix);

        if(prefix.length()==0) {
            currentUri = fixNull(currentUri);
            if(currentUri.equals(uri))
                return; // declared correctly
        } else {
            if(currentUri!=null && currentUri.equals(uri))
                return; // declared correctly
        }

        if(prefix.equals("xml") || prefix.equals("xmlns"))
            return; // implicitly declared namespaces

        // needs to be declared
        scope.additionalNamespaces.add(prefix);
        scope.additionalNamespaces.add(uri);
    }

    
Allocate new Scope for splitAttributes(). /**
     * Allocate new {@link Scope} for {@link #splitAttributes()}.
     */
    private Scope allocateScope() {
        if(scopes.length==++depth) {
            Scope[] newBuf = new Scope[scopes.length*2];
            System.arraycopy(scopes,0,newBuf,0,scopes.length);
            scopes = newBuf;
        }
        Scope scope = scopes[depth];
        if(scope==null) {
            scope = scopes[depth] = new Scope(scopes[depth-1]);
        } else {
            scope.reset();
        }
        return scope;
    }

    public int getAttributeCount() {
        if (_state == START_ELEMENT)
            return _currentAttributes.size();
        throw new IllegalStateException("DOMStreamReader: getAttributeCount() called in illegal state");
    }

    
Return an attribute's local name. Handle the case of DOM level 1 nodes.
/**
     * Return an attribute's local name. Handle the case of DOM level 1 nodes.
     */
    public String getAttributeLocalName(int index) {
        if (_state == START_ELEMENT) {
            String localName = _currentAttributes.get(index).getLocalName();
            return (localName != null) ? localName :
                QName.valueOf(_currentAttributes.get(index).getNodeName()).getLocalPart();
        }
        throw new IllegalStateException("DOMStreamReader: getAttributeLocalName() called in illegal state");
    }

    
Return an attribute's qname. Handle the case of DOM level 1 nodes.
/**
     * Return an attribute's qname. Handle the case of DOM level 1 nodes.
     */
    public QName getAttributeName(int index) {
        if (_state == START_ELEMENT) {
            Node attr = _currentAttributes.get(index);
            String localName = attr.getLocalName();
            if (localName != null) {
                String prefix = attr.getPrefix();
                String uri = attr.getNamespaceURI();
                return new QName(fixNull(uri), localName, fixNull(prefix));
            }
            else {
                return QName.valueOf(attr.getNodeName());
            }
        }
        throw new IllegalStateException("DOMStreamReader: getAttributeName() called in illegal state");
    }

    public String getAttributeNamespace(int index) {
        if (_state == START_ELEMENT) {
            String uri = _currentAttributes.get(index).getNamespaceURI();
            return fixNull(uri);
        }
        throw new IllegalStateException("DOMStreamReader: getAttributeNamespace() called in illegal state");
    }

    public String getAttributePrefix(int index) {
        if (_state == START_ELEMENT) {
            String prefix = _currentAttributes.get(index).getPrefix();
            return fixNull(prefix);
        }
        throw new IllegalStateException("DOMStreamReader: getAttributePrefix() called in illegal state");
    }

    public String getAttributeType(int index) {
        if (_state == START_ELEMENT) {
            return "CDATA";
        }
        throw new IllegalStateException("DOMStreamReader: getAttributeType() called in illegal state");
    }

    public String getAttributeValue(int index) {
        if (_state == START_ELEMENT) {
            return _currentAttributes.get(index).getNodeValue();
        }
        throw new IllegalStateException("DOMStreamReader: getAttributeValue() called in illegal state");
    }

    public String getAttributeValue(String namespaceURI, String localName) {
        if (_state == START_ELEMENT) {
            if (_namedNodeMap != null) {
                Node attr = _namedNodeMap.getNamedItemNS(namespaceURI, localName);
                return attr != null ? attr.getNodeValue() : null;
            }
            return null;
        }
        throw new IllegalStateException("DOMStreamReader: getAttributeValue() called in illegal state");
    }

    public String getCharacterEncodingScheme() {
        return null;
    }

    public String getElementText() throws javax.xml.stream.XMLStreamException {
        throw new RuntimeException("DOMStreamReader: getElementText() not implemented");
    }

    public String getEncoding() {
        return null;
    }

    public int getEventType() {
        return _state;
    }

    
Return an element's local name. Handle the case of DOM level 1 nodes.
/**
     * Return an element's local name. Handle the case of DOM level 1 nodes.
     */
    public String getLocalName() {
        if (_state == START_ELEMENT || _state == END_ELEMENT) {
            String localName = _current.getLocalName();
            return localName != null ? localName :
                QName.valueOf(_current.getNodeName()).getLocalPart();
        }
        else if (_state == ENTITY_REFERENCE) {
            return _current.getNodeName();
        }
        throw new IllegalStateException("DOMStreamReader: getAttributeValue() called in illegal state");
    }

    public Location getLocation() {
        return DummyLocation.INSTANCE;
    }

    
Return an element's qname. Handle the case of DOM level 1 nodes.
/**
     * Return an element's qname. Handle the case of DOM level 1 nodes.
     */
    public javax.xml.namespace.QName getName() {
        if (_state == START_ELEMENT || _state == END_ELEMENT) {
            String localName = _current.getLocalName();
            if (localName != null) {
                String prefix = _current.getPrefix();
                String uri = _current.getNamespaceURI();
                return new QName(fixNull(uri), localName, fixNull(prefix));
            }
            else {
                return QName.valueOf(_current.getNodeName());
            }
        }
        throw new IllegalStateException("DOMStreamReader: getName() called in illegal state");
    }

    public NamespaceContext getNamespaceContext() {
        return this;
    }

    
Verifies the current state to see if we can return the scope, and do so
if appropriate.
Used to implement a bunch of StAX API methods that have the same usage restriction.
/**
     * Verifies the current state to see if we can return the scope, and do so
     * if appropriate.
     *
     * Used to implement a bunch of StAX API methods that have the same usage restriction.
     */
    private Scope getCheckedScope() {
        if (_state == START_ELEMENT || _state == END_ELEMENT) {
            return scopes[depth];
        }
        throw new IllegalStateException("DOMStreamReader: neither on START_ELEMENT nor END_ELEMENT");
    }

    public int getNamespaceCount() {
        return getCheckedScope().getNamespaceCount();
    }

    public String getNamespacePrefix(int index) {
        return getCheckedScope().getNamespacePrefix(index);
    }

    public String getNamespaceURI(int index) {
        return getCheckedScope().getNamespaceURI(index);
    }

    public String getNamespaceURI() {
        if (_state == START_ELEMENT || _state == END_ELEMENT) {
            String uri = _current.getNamespaceURI();
            return fixNull(uri);
        }
        return null;
    }

    
This method is not particularly fast, but shouldn't be called very
often. If we start to use it more, we should keep track of the
NS declarations using a NamespaceContext implementation instead.
/**
     * This method is not particularly fast, but shouldn't be called very
     * often. If we start to use it more, we should keep track of the
     * NS declarations using a NamespaceContext implementation instead.
     */
    public String getNamespaceURI(String prefix) {
        if (prefix == null) {
            throw new IllegalArgumentException("DOMStreamReader: getNamespaceURI(String) call with a null prefix");
        }
        else if (prefix.equals("xml")) {
            return "http://www.w3.org/XML/1998/namespace";
        }
        else if (prefix.equals("xmlns")) {
            return "http://www.w3.org/2000/xmlns/";
        }

        // check scopes
        String nsUri = scopes[depth].getNamespaceURI(prefix);
        if(nsUri!=null)    return nsUri;

        // then ancestors above start node
        Node node = findRootElement();
        String nsDeclName = prefix.length()==0 ? "xmlns" : "xmlns:"+prefix;
        while (node.getNodeType() != DOCUMENT_NODE) {
            // Is ns declaration on this element?
            NamedNodeMap namedNodeMap = node.getAttributes();
            Attr attr = (Attr) namedNodeMap.getNamedItem(nsDeclName);
            if (attr != null)
                return attr.getValue();
            node = node.getParentNode();
        }
        return null;
    }

    public String getPrefix(String nsUri) {
        if (nsUri == null) {
            throw new IllegalArgumentException("DOMStreamReader: getPrefix(String) call with a null namespace URI");
        }
        else if (nsUri.equals("http://www.w3.org/XML/1998/namespace")) {
            return "xml";
        }
        else if (nsUri.equals("http://www.w3.org/2000/xmlns/")) {
            return "xmlns";
        }

        // check scopes
        String prefix = scopes[depth].getPrefix(nsUri);
        if(prefix!=null)    return prefix;

        // then ancestors above start node
        Node node = findRootElement();

        while (node.getNodeType() != DOCUMENT_NODE) {
            // Is ns declaration on this element?
            NamedNodeMap namedNodeMap = node.getAttributes();
            for( int i=namedNodeMap.getLength()-1; i>=0; i-- ) {
                Attr attr = (Attr)namedNodeMap.item(i);
                prefix = getPrefixForAttr(attr,nsUri);
                if(prefix!=null)
                    return prefix;
            }
            node = node.getParentNode();
        }
        return null;
    }

    
Finds the root element node of the traversal.
/**
     * Finds the root element node of the traversal.
     */
    private Node findRootElement() {
        int type;

        Node node = _start;
        while ((type = node.getNodeType()) != DOCUMENT_NODE
                && type != ELEMENT_NODE) {
            node = node.getParentNode();
        }
        return node;
    }

    
If the given attribute is a namespace declaration for the given namespace URI,
return its prefix. Otherwise null.
/**
     * If the given attribute is a namespace declaration for the given namespace URI,
     * return its prefix. Otherwise null.
     */
    private static String getPrefixForAttr(Attr attr, String nsUri) {
        String attrName = attr.getNodeName();
        if (!attrName.startsWith("xmlns:") && !attrName.equals("xmlns"))
            return null;    // not nsdecl

        if(attr.getValue().equals(nsUri)) {
            if(attrName.equals("xmlns"))
                return "";
            String localName = attr.getLocalName();
            return (localName != null) ? localName :
                QName.valueOf(attrName).getLocalPart();
        }

        return null;
    }

    public Iterator getPrefixes(String nsUri) {
        // This is an incorrect implementation,
        // but AFAIK it's not used in the JAX-WS runtime
        String prefix = getPrefix(nsUri);
        if(prefix==null)    return Collections.emptyList().iterator();
        else                return Collections.singletonList(prefix).iterator();
    }

    public String getPIData() {
        if (_state == PROCESSING_INSTRUCTION) {
            return ((ProcessingInstruction) _current).getData();
        }
        return null;
    }

    public String getPITarget() {
        if (_state == PROCESSING_INSTRUCTION) {
            return ((ProcessingInstruction) _current).getTarget();
        }
        return null;
    }

    public String getPrefix() {
        if (_state == START_ELEMENT || _state == END_ELEMENT) {
            String prefix = _current.getPrefix();
            return fixNull(prefix);
        }
        return null;
    }

    public Object getProperty(String str) throws IllegalArgumentException {
        return null;
    }

    public String getText() {
        if (_state == CHARACTERS)
            return wholeText;
        if(_state == CDATA || _state == COMMENT || _state == ENTITY_REFERENCE)
            return _current.getNodeValue();
        throw new IllegalStateException("DOMStreamReader: getTextLength() called in illegal state");
    }

    public char[] getTextCharacters() {
        return getText().toCharArray();
    }

    public int getTextCharacters(int sourceStart, char[] target, int targetStart,
                                 int targetLength) throws XMLStreamException {
        String text = getText();
        int copiedSize = Math.min(targetLength, text.length() - sourceStart);
        text.getChars(sourceStart, sourceStart + copiedSize, target, targetStart);

        return copiedSize;
    }

    public int getTextLength() {
        return getText().length();
    }

    public int getTextStart() {
        if (_state == CHARACTERS || _state == CDATA || _state == COMMENT || _state == ENTITY_REFERENCE) {
            return 0;
        }
        throw new IllegalStateException("DOMStreamReader: getTextStart() called in illegal state");
    }

    public String getVersion() {
        return null;
    }

    public boolean hasName() {
        return (_state == START_ELEMENT || _state == END_ELEMENT);
    }

    public boolean hasNext() throws javax.xml.stream.XMLStreamException {
        return (_state != END_DOCUMENT);
    }

    public boolean hasText() {
        if (_state == CHARACTERS || _state == CDATA || _state == COMMENT || _state == ENTITY_REFERENCE) {
            return getText().trim().length() > 0;
        }
        return false;
    }

    public boolean isAttributeSpecified(int param) {
        return false;
    }

    public boolean isCharacters() {
        return (_state == CHARACTERS);
    }

    public boolean isEndElement() {
        return (_state == END_ELEMENT);
    }

    public boolean isStandalone() {
        return true;
    }

    public boolean isStartElement() {
        return (_state == START_ELEMENT);
    }

    public boolean isWhiteSpace() {
        if (_state == CHARACTERS || _state == CDATA)
            return getText().trim().length()==0;
        return false;
    }

    private static int mapNodeTypeToState(int nodetype) {
        switch (nodetype) {
            case CDATA_SECTION_NODE:
                return CDATA;
            case COMMENT_NODE:
                return COMMENT;
            case ELEMENT_NODE:
                return START_ELEMENT;
            case ENTITY_NODE:
                return ENTITY_DECLARATION;
            case ENTITY_REFERENCE_NODE:
                return ENTITY_REFERENCE;
            case NOTATION_NODE:
                return NOTATION_DECLARATION;
            case PROCESSING_INSTRUCTION_NODE:
                return PROCESSING_INSTRUCTION;
            case TEXT_NODE:
                return CHARACTERS;
            default:
                throw new RuntimeException("DOMStreamReader: Unexpected node type");
        }
    }

    public int next() throws XMLStreamException {
        while(true) {
            int r = _next();
            switch (r) {
            case CHARACTERS:
                // if we are currently at text node, make sure that this is a meaningful text node.
                Node prev = _current.getPreviousSibling();
                if(prev!=null && prev.getNodeType()==Node.TEXT_NODE)
                    continue;   // nope. this is just a continuation of previous text that should be invisible

                Text t = (Text)_current;
                wholeText = t.getWholeText();
                if(wholeText.length()==0)
                    continue;   // nope. this is empty text.
                return CHARACTERS;
            case START_ELEMENT:
                splitAttributes();
                return START_ELEMENT;
            default:
                return r;
            }
        }
    }

    protected int _next() throws XMLStreamException {
        Node child;

        switch (_state) {
            case END_DOCUMENT:
                throw new IllegalStateException("DOMStreamReader: Calling next() at END_DOCUMENT");
            case START_DOCUMENT:
                // Don't skip document element if this is a fragment
                if (_current.getNodeType() == ELEMENT_NODE) {
                    return (_state = START_ELEMENT);
                }

                child = _current.getFirstChild();
                if (child == null) {
                    return (_state = END_DOCUMENT);
                }
                else {
                    _current = child;
                    return (_state = mapNodeTypeToState(_current.getNodeType()));
                }
            case START_ELEMENT:
                child = _current.getFirstChild();
                if (child == null) {
                    return (_state = END_ELEMENT);
                }
                else {
                    _current = child;
                    return (_state = mapNodeTypeToState(_current.getNodeType()));
                }
            case END_ELEMENT:
                depth--;
                // fall through next
            case CHARACTERS:
            case COMMENT:
            case CDATA:
            case ENTITY_REFERENCE:
            case PROCESSING_INSTRUCTION:
                // If at the end of this fragment, then terminate traversal
                if (_current == _start) {
                    return (_state = END_DOCUMENT);
                }

                Node sibling = _current.getNextSibling();
                if (sibling == null) {
                    _current = _current.getParentNode();
                    // getParentNode() returns null for fragments
                    _state = (_current == null || _current.getNodeType() == DOCUMENT_NODE) ?
                             END_DOCUMENT : END_ELEMENT;
                    return _state;
                }
                else {
                    _current = sibling;
                    return (_state = mapNodeTypeToState(_current.getNodeType()));
                }
            case DTD:
            case ATTRIBUTE:
            case NAMESPACE:
            default:
                throw new RuntimeException("DOMStreamReader: Unexpected internal state");
        }
    }

    public int nextTag() throws javax.xml.stream.XMLStreamException {
        int eventType = next();
        while (eventType == CHARACTERS && isWhiteSpace()
               || eventType == CDATA && isWhiteSpace()
               || eventType == SPACE
               || eventType == PROCESSING_INSTRUCTION
               || eventType == COMMENT)
        {
            eventType = next();
        }
        if (eventType != START_ELEMENT && eventType != END_ELEMENT) {
            throw new XMLStreamException2("DOMStreamReader: Expected start or end tag");
        }
        return eventType;
    }

    public void require(int type, String namespaceURI, String localName)
        throws javax.xml.stream.XMLStreamException
    {
        if (type != _state) {
            throw new XMLStreamException2("DOMStreamReader: Required event type not found");
        }
        if (namespaceURI != null && !namespaceURI.equals(getNamespaceURI())) {
            throw new XMLStreamException2("DOMStreamReader: Required namespaceURI not found");
        }
        if (localName != null && !localName.equals(getLocalName())) {
            throw new XMLStreamException2("DOMStreamReader: Required localName not found");
        }
    }

    public boolean standaloneSet() {
        return true;
    }



    // -- Debugging ------------------------------------------------------

    private static void displayDOM(Node node, java.io.OutputStream ostream) {
        try {
            System.out.println("\n====\n");
            XmlUtil.newTransformer().transform(
                new DOMSource(node), new StreamResult(ostream));
            System.out.println("\n====\n");
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static void verifyDOMIntegrity(Node node) {
        switch (node.getNodeType()) {
            case ELEMENT_NODE:
            case ATTRIBUTE_NODE:

                // DOM level 1?
                if (node.getLocalName() == null) {
                    System.out.println("WARNING: DOM level 1 node found");
                    System.out.println(" -> node.getNodeName() = " + node.getNodeName());
                    System.out.println(" -> node.getNamespaceURI() = " + node.getNamespaceURI());
                    System.out.println(" -> node.getLocalName() = " + node.getLocalName());
                    System.out.println(" -> node.getPrefix() = " + node.getPrefix());
                }

                if (node.getNodeType() == ATTRIBUTE_NODE) return;

                NamedNodeMap attrs = node.getAttributes();
                for (int i = 0; i < attrs.getLength(); i++) {
                    verifyDOMIntegrity(attrs.item(i));
                }
            case DOCUMENT_NODE:
                NodeList children = node.getChildNodes();
                for (int i = 0; i < children.getLength(); i++) {
                    verifyDOMIntegrity(children.item(i));
                }
        }
    }


    private static String fixNull(String s) {
        if(s==null) return "";
        else        return s;
    }
}