net.sf.saxon.option.dom4j.NodeWrapper.java Source code

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Here is the source code for net.sf.saxon.option.dom4j.NodeWrapper.java

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package net.sf.saxon.option.dom4j;

import net.sf.saxon.Configuration;
import net.sf.saxon.event.Receiver;
import net.sf.saxon.om.*;
import net.sf.saxon.pattern.AnyNodeTest;
import net.sf.saxon.pattern.NodeTest;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.tree.NamespaceNode;
import net.sf.saxon.tree.iter.AxisIterator;
import net.sf.saxon.tree.iter.EmptyAxisIterator;
import net.sf.saxon.tree.iter.SingletonIterator;
import net.sf.saxon.tree.util.FastStringBuffer;
import net.sf.saxon.tree.util.Navigator;
import net.sf.saxon.tree.wrapper.SiblingCountingNode;
import net.sf.saxon.tree.wrapper.VirtualNode;
import net.sf.saxon.type.BuiltInAtomicType;
import net.sf.saxon.type.SchemaType;
import net.sf.saxon.type.Type;
import net.sf.saxon.type.Untyped;
import net.sf.saxon.value.AtomicValue;
import net.sf.saxon.value.StringValue;
import net.sf.saxon.value.UntypedAtomicValue;
import net.sf.saxon.value.Value;
import org.dom4j.*;

import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;

/**
  * A node in the XML parse tree representing an XML element, character content, or attribute.<P>
  * This is the implementation of the NodeInfo interface used as a wrapper for DOM4J nodes.
  * @author Michael H. Kay
  */

// History: this started life as the NodeWrapper for JDOM nodes; it was then modified by the
// Orbeon team to act as a wrapper for DOM4J nodes, and was shipped with the Orbeon product;
// it has now been absorbed back into Saxon.

public class NodeWrapper implements NodeInfo, VirtualNode, SiblingCountingNode {

    protected Object node;
    protected short nodeKind;
    /*@Nullable*/ private NodeWrapper parent; // null means unknown
    protected DocumentWrapper docWrapper;
    // Beware: with dom4j, this is an index over the result of content(), which may contain Namespace nodes
    protected int index; // -1 means unknown

    /**
     * This constructor is protected: nodes should be created using the wrap
     * factory method on the DocumentWrapper class
     * @param node    The DOM4J node to be wrapped
     * @param parent  The NodeWrapper that wraps the parent of this node
     * @param index   Position of this node among its siblings
     */
    protected NodeWrapper(Object node, NodeWrapper parent, int index) {
        this.node = node;
        this.parent = parent;
        this.index = index;
    }

    /**
     * Factory method to wrap a DOM4J node with a wrapper that implements the Saxon
     * NodeInfo interface.
     * @param node        The DOM4J node
     * @param docWrapper  The wrapper for the Document containing this node
     * @return            The new wrapper for the supplied node
     */
    protected NodeWrapper makeWrapper(Object node, DocumentWrapper docWrapper) {
        return makeWrapper(node, docWrapper, null, -1);
    }

    /**
     * Factory method to wrap a DOM4J node with a wrapper that implements the Saxon
     * NodeInfo interface.
     * @param node        The DOM4J node
     * @param docWrapper  The wrapper for the Document containing this node
     * @param parent      The wrapper for the parent of the DOM4J node
     * @param index       The position of this node relative to its siblings
     * @return            The new wrapper for the supplied node
     */

    protected NodeWrapper makeWrapper(Object node, DocumentWrapper docWrapper, NodeWrapper parent, int index) {
        NodeWrapper wrapper;
        if (node instanceof Document) {
            return docWrapper;
        } else if (node instanceof Element) {
            wrapper = new NodeWrapper(node, parent, index);
            wrapper.nodeKind = Type.ELEMENT;
        } else if (node instanceof Attribute) {
            wrapper = new NodeWrapper(node, parent, index);
            wrapper.nodeKind = Type.ATTRIBUTE;
        } else if (node instanceof String || node instanceof Text || node instanceof CDATA) {
            wrapper = new NodeWrapper(node, parent, index);
            wrapper.nodeKind = Type.TEXT;
        } else if (node instanceof Comment) {
            wrapper = new NodeWrapper(node, parent, index);
            wrapper.nodeKind = Type.COMMENT;
        } else if (node instanceof ProcessingInstruction) {
            wrapper = new NodeWrapper(node, parent, index);
            wrapper.nodeKind = Type.PROCESSING_INSTRUCTION;
        } else if (node instanceof Namespace) {
            wrapper = new NodeWrapper(node, parent, index);
            wrapper.nodeKind = Type.NAMESPACE;
        } else {
            throw new IllegalArgumentException(
                    "Bad node type in dom4j! " + node.getClass() + " instance " + node.toString());
        }
        wrapper.docWrapper = docWrapper;
        return wrapper;
    }

    /**
    * Get the underlying DOM node, to implement the VirtualNode interface
    */

    public Object getUnderlyingNode() {
        return node;
    }

    /**
     * Get the node underlying this virtual node. If this is a VirtualNode the method
     * will automatically drill down through several layers of wrapping.
     * @return The underlying node.
     */

    public Object getRealNode() {
        return getUnderlyingNode();
    }

    /**
     * Get the name pool for this node
     * @return the NamePool
     */

    public NamePool getNamePool() {
        return docWrapper.getNamePool();
    }

    /**
    * Return the type of node.
    * @return one of the values Node.ELEMENT, Node.TEXT, Node.ATTRIBUTE, etc.
    */
    public int getNodeKind() {
        return nodeKind;
    }

    /**
    * Get the typed value of the item
    */
    public SequenceIterator getTypedValue() {
        return SingletonIterator.makeIterator((AtomicValue) atomize());
    }

    public Value atomize() {
        switch (getNodeKind()) {
        case Type.COMMENT:
        case Type.PROCESSING_INSTRUCTION:
            return new StringValue(getStringValueCS());
        default:
            return new UntypedAtomicValue(getStringValueCS());
        }
    }

    /**
     * Get the type annotation
     */

    public int getTypeAnnotation() {
        SchemaType st = getSchemaType();
        return (st == null ? -1 : st.getFingerprint());
    }

    /**
     * Get the type annotation of this node, if any. The type annotation is represented as
     * SchemaType object.
     * <p/>
     * <p>Types derived from a DTD are not reflected in the result of this method.</p>
     *
     * @return For element and attribute nodes: the type annotation derived from schema
     *         validation (defaulting to xs:untyped and xs:untypedAtomic in the absence of schema
     *         validation). For comments, text nodes, processing instructions, and namespaces: null.
     *         For document nodes, either xs:untyped if the document has not been validated, or
     *         xs:anyType if it has.
     * @since 9.4
     */

    public SchemaType getSchemaType() {
        if (getNodeKind() == Type.ATTRIBUTE) {
            return BuiltInAtomicType.UNTYPED_ATOMIC;
        } else {
            return Untyped.getInstance();
        }
    }

    /**
     * Determine whether this is the same node as another node. <br />
     * Note: a.isSameNode(b) if and only if generateId(a)==generateId(b)
     * @param other the node to be compared with
     * @return true if this Node object and the supplied Node object represent the
     * same node in the tree.
    */

    public boolean isSameNode(NodeInfo other) {
        if (!(other instanceof NodeWrapper)) {
            return false;
        }
        NodeWrapper ow = (NodeWrapper) other;
        return node.equals(ow.node);
    }

    /**
    * Get the System ID for the node.
    * @return the System Identifier of the entity in the source document containing the node,
    * or null if not known. Note this is not the same as the base URI: the base URI can be
    * modified by xml:base, but the system ID cannot.
    */

    public String getSystemId() {
        return docWrapper.baseURI;
    }

    public void setSystemId(String uri) {
        docWrapper.baseURI = uri;
    }

    /**
    * Get the Base URI for the node, that is, the URI used for resolving a relative URI contained
     * in the node. In the DOM4J model, base URIs are held only an the document level. We don't
     * currently take any account of xml:base attributes.
    */

    public String getBaseURI() {
        if (getNodeKind() == Type.NAMESPACE) {
            return null;
        }
        NodeInfo n = this;
        if (getNodeKind() != Type.ELEMENT) {
            n = n.getParent();
        }
        // Look for an xml:base attribute
        while (n != null) {
            String xmlbase = n.getAttributeValue(StandardNames.XML_BASE);
            if (xmlbase != null) {
                return xmlbase;
            }
            n = n.getParent();
        }
        // if not found, return the base URI of the document node
        return docWrapper.baseURI;
    }

    /**
    * Get line number
    * @return the line number of the node in its original source document; or -1 if not available
    */

    public int getLineNumber() {
        return -1;
    }

    /**
      * Get column number
      * @return the column number of the node in its original source document; or -1 if not available
      */

    public int getColumnNumber() {
        return -1;
    }

    /**
    * Determine the relative position of this node and another node, in document order.
    * The other node will always be in the same document.
    * @param other The other node, whose position is to be compared with this node
    * @return -1 if this node precedes the other node, +1 if it follows the other
    * node, or 0 if they are the same node. (In this case, isSameNode() will always
    * return true, and the two nodes will produce the same result for generateId())
    */

    public int compareOrder(NodeInfo other) {
        return Navigator.compareOrder(this, (SiblingCountingNode) other);
    }

    /**
    * Return the string value of the node. The interpretation of this depends on the type
    * of node. For an element it is the accumulated character content of the element,
    * including descendant elements.
    * @return the string value of the node
    */

    public String getStringValue() {
        return getStringValue(node);
    }

    public CharSequence getStringValueCS() {
        return getStringValue(node);
    }

    private static String getStringValue(Object node) {
        if (node instanceof Document) {
            return ((Document) node).getStringValue();
        } else if (node instanceof Element) {
            return ((Element) node).getStringValue();
        } else if (node instanceof Attribute) {
            return ((Attribute) node).getValue();
        } else if (node instanceof Text) {
            return ((Text) node).getText();
        } else if (node instanceof CDATA) {
            return ((CDATA) node).getText();
        } else if (node instanceof String) {
            return (String) node;
        } else if (node instanceof Comment) {
            return ((Comment) node).getText();
        } else if (node instanceof ProcessingInstruction) {
            return ((ProcessingInstruction) node).getStringValue();
        } else if (node instanceof Namespace) {
            return ((Namespace) node).getURI();
        } else {
            return "";
        }
    }

    /**
    * Get name code. The name code is a coded form of the node name: two nodes
    * with the same name code have the same namespace URI, the same local name,
    * and the same prefix. By masking the name code with &0xfffff, you get a
    * fingerprint: two nodes with the same fingerprint have the same local name
    * and namespace URI.
    * @see net.sf.saxon.om.NamePool#allocate allocate
    */

    public int getNameCode() {
        switch (nodeKind) {
        case Type.ELEMENT:
        case Type.ATTRIBUTE:
        case Type.PROCESSING_INSTRUCTION:
        case Type.NAMESPACE:
            return docWrapper.getNamePool().allocate(getPrefix(), getURI(), getLocalPart());
        default:
            return -1;
        }
    }

    /**
    * Get fingerprint. The fingerprint is a coded form of the expanded name
    * of the node: two nodes
    * with the same name code have the same namespace URI and the same local name.
    * A fingerprint of -1 should be returned for a node with no name.
    */

    public int getFingerprint() {
        return getNameCode() & 0xfffff;
    }

    /**
    * Get the local part of the name of this node. This is the name after the ":" if any.
    * @return the local part of the name. For an unnamed node, returns "".
    */

    public String getLocalPart() {
        switch (nodeKind) {
        case Type.ELEMENT:
            return ((Element) node).getName();
        case Type.ATTRIBUTE:
            return ((Attribute) node).getName();
        case Type.TEXT:
        case Type.COMMENT:
        case Type.DOCUMENT:
            return "";
        case Type.PROCESSING_INSTRUCTION:
            return ((ProcessingInstruction) node).getTarget();
        case Type.NAMESPACE:
            return ((Namespace) node).getPrefix();
        default:
            return null;
        }
    }

    /**
    * Get the prefix part of the name of this node. This is the name before the ":" if any.
     * (Note, this method isn't required as part of the NodeInfo interface.)
    * @return the prefix part of the name. For an unnamed node, return an empty string.
    */

    public String getPrefix() {
        switch (nodeKind) {
        case Type.ELEMENT:
            return ((Element) node).getNamespacePrefix();
        case Type.ATTRIBUTE:
            return ((Attribute) node).getNamespacePrefix();
        default:
            return "";
        }
    }

    /**
    * Get the URI part of the name of this node. This is the URI corresponding to the
    * prefix, or the URI of the default namespace if appropriate.
    * @return The URI of the namespace of this node. For an unnamed node, return null.
    * For a node with an empty prefix, return an empty string.
    */

    public String getURI() {
        switch (nodeKind) {
        case Type.ELEMENT:
            return ((Element) node).getNamespaceURI();
        case Type.ATTRIBUTE:
            return ((Attribute) node).getNamespaceURI();
        default:
            return "";
        }
    }

    /**
    * Get the display name of this node. For elements and attributes this is [prefix:]localname.
    * For unnamed nodes, it is an empty string.
    * @return The display name of this node.
    * For a node with no name, return an empty string.
    */

    public String getDisplayName() {
        switch (nodeKind) {
        case Type.ELEMENT:
            return ((Element) node).getQualifiedName();
        case Type.ATTRIBUTE:
            return ((Attribute) node).getQualifiedName();
        case Type.PROCESSING_INSTRUCTION:
        case Type.NAMESPACE:
            return getLocalPart();
        default:
            return "";

        }
    }

    /**
    * Get the NodeInfo object representing the parent of this node
    */

    public NodeInfo getParent() {
        if (parent == null) {
            if (node instanceof Element) {
                if (((Element) node).isRootElement()) {
                    parent = makeWrapper(((Element) node).getDocument(), docWrapper);
                } else {
                    parent = makeWrapper(((Element) node).getParent(), docWrapper);
                }
            } else if (node instanceof Text) {
                parent = makeWrapper(((Text) node).getParent(), docWrapper);
            } else if (node instanceof CDATA) {
                parent = makeWrapper(((CDATA) node).getParent(), docWrapper);
            } else if (node instanceof Comment) {
                parent = makeWrapper(((Comment) node).getParent(), docWrapper);
            } else if (node instanceof ProcessingInstruction) {
                parent = makeWrapper(((ProcessingInstruction) node).getParent(), docWrapper);
            } else if (node instanceof Attribute) {
                parent = makeWrapper(((Attribute) node).getParent(), docWrapper);
            } else if (node instanceof Document) {
                parent = null;
            } else if (node instanceof Namespace) {
                throw new UnsupportedOperationException("Cannot find parent of DOM4J namespace node");
            } else {
                throw new IllegalStateException("Unknown DOM4J node type " + node.getClass());
            }
        }
        return parent;
    }

    /**
     * Get the index position of this node among its siblings (starting from 0)
     */
    public int getSiblingPosition() {
        if (index == -1) {
            int ix = 0;
            getParent();
            AxisIterator iter;
            switch (nodeKind) {
            case Type.ELEMENT:
            case Type.TEXT:
            case Type.COMMENT:
            case Type.PROCESSING_INSTRUCTION:
            //                    iter = parent.iterateAxis(Axis.ATTRIBUTE);
            //                    break;
            {
                final NodeWrapper parent = (NodeWrapper) getParent();
                final List children;
                if (parent.getNodeKind() == Type.DOCUMENT) {
                    children = ((Document) parent.node).content();
                } else {
                    // Beware: dom4j content() contains Namespace nodes (which is broken)!
                    children = ((Element) parent.node).content();
                }
                for (ListIterator iterator = children.listIterator(); iterator.hasNext();) {
                    final Object n = iterator.next();
                    if (n == node) {
                        index = ix;
                        return index;
                    }
                    ix++;
                }
                throw new IllegalStateException("DOM4J node not linked to parent node");
            }
            case Type.ATTRIBUTE:
                iter = parent.iterateAxis(Axis.ATTRIBUTE);
                break;
            case Type.NAMESPACE:
                iter = parent.iterateAxis(Axis.NAMESPACE);
                break;
            default:
                index = 0;
                return index;
            }
            while (true) {
                NodeInfo n = (NodeInfo) iter.next();
                if (n == null) {
                    break;
                }
                if (n.isSameNodeInfo(this)) {
                    index = ix;
                    return index;
                }
                ix++;
            }
            throw new IllegalStateException("DOM4J node not linked to parent node");
        }
        return index;
    }

    /**
    * Return an iteration over the nodes reached by the given axis from this node
    * @param axisNumber the axis to be used
    * @return a SequenceIterator that scans the nodes reached by the axis in turn.
    */

    public AxisIterator iterateAxis(byte axisNumber) {
        return iterateAxis(axisNumber, AnyNodeTest.getInstance());
    }

    /**
    * Return an iteration over the nodes reached by the given axis from this node
    * @param axisNumber the axis to be used
    * @param nodeTest A pattern to be matched by the returned nodes
    * @return a SequenceIterator that scans the nodes reached by the axis in turn.
    */

    public AxisIterator iterateAxis(byte axisNumber, NodeTest nodeTest) {
        switch (axisNumber) {
        case Axis.ANCESTOR:
            if (nodeKind == Type.DOCUMENT) {
                return EmptyAxisIterator.emptyAxisIterator();
            }
            return new Navigator.AxisFilter(new Navigator.AncestorEnumeration(this, false), nodeTest);

        case Axis.ANCESTOR_OR_SELF:
            if (nodeKind == Type.DOCUMENT) {
                return Navigator.filteredSingleton(this, nodeTest);
            }
            return new Navigator.AxisFilter(new Navigator.AncestorEnumeration(this, true), nodeTest);

        case Axis.ATTRIBUTE:
            if (nodeKind != Type.ELEMENT) {
                return EmptyAxisIterator.emptyAxisIterator();
            }
            return new Navigator.AxisFilter(new AttributeEnumeration(this), nodeTest);

        case Axis.CHILD:
            if (hasChildNodes()) {
                return new Navigator.AxisFilter(new ChildEnumeration(this, true, true), nodeTest);
            } else {
                return EmptyAxisIterator.emptyAxisIterator();
            }

        case Axis.DESCENDANT:
            if (hasChildNodes()) {
                return new Navigator.AxisFilter(new Navigator.DescendantEnumeration(this, false, true), nodeTest);
            } else {
                return EmptyAxisIterator.emptyAxisIterator();
            }

        case Axis.DESCENDANT_OR_SELF:
            return new Navigator.AxisFilter(new Navigator.DescendantEnumeration(this, true, true), nodeTest);

        case Axis.FOLLOWING:
            return new Navigator.AxisFilter(new Navigator.FollowingEnumeration(this), nodeTest);

        case Axis.FOLLOWING_SIBLING:
            switch (nodeKind) {
            case Type.DOCUMENT:
            case Type.ATTRIBUTE:
            case Type.NAMESPACE:
                return EmptyAxisIterator.emptyAxisIterator();
            default:
                return new Navigator.AxisFilter(new ChildEnumeration(this, false, true), nodeTest);
            }

        case Axis.NAMESPACE:
            if (nodeKind != Type.ELEMENT) {
                return EmptyAxisIterator.emptyAxisIterator();
            }
            return NamespaceNode.makeIterator(this, nodeTest);

        case Axis.PARENT:
            getParent();
            return Navigator.filteredSingleton(parent, nodeTest);

        case Axis.PRECEDING:
            return new Navigator.AxisFilter(new Navigator.PrecedingEnumeration(this, false), nodeTest);

        case Axis.PRECEDING_SIBLING:
            switch (nodeKind) {
            case Type.DOCUMENT:
            case Type.ATTRIBUTE:
            case Type.NAMESPACE:
                return EmptyAxisIterator.emptyAxisIterator();
            default:
                return new Navigator.AxisFilter(new ChildEnumeration(this, false, false), nodeTest);
            }

        case Axis.SELF:
            return Navigator.filteredSingleton(this, nodeTest);

        case Axis.PRECEDING_OR_ANCESTOR:
            return new Navigator.AxisFilter(new Navigator.PrecedingEnumeration(this, true), nodeTest);

        default:
            throw new IllegalArgumentException("Unknown axis number " + axisNumber);
        }
    }

    /**
    * Get the value of a given attribute of this node
    * @param fingerprint The fingerprint of the attribute name
    * @return the attribute value if it exists or null if not
    */

    public String getAttributeValue(int fingerprint) {
        if (nodeKind == Type.ELEMENT) {
            Iterator list = ((Element) node).attributes().iterator();
            NamePool pool = docWrapper.getNamePool();
            while (list.hasNext()) {
                Attribute att = (Attribute) list.next();
                int nameCode = pool.allocate(att.getNamespacePrefix(), att.getNamespaceURI(), att.getName());
                if (fingerprint == (nameCode & 0xfffff)) {
                    return att.getValue();
                }
            }
        }
        return null;
    }

    /**
     * Get the string value of a given attribute of this node
     *
     * @param uri   the namespace URI of the attribute name. Supply the empty string for an attribute
     *              that is in no namespace
     * @param local the local part of the attribute name.
     * @return the attribute value if it exists, or null if it does not exist. Always returns null
     *         if this node is not an element.
     * @since 9.4
     */
    public String getAttributeValue(/*@NotNull*/ String uri, /*@NotNull*/ String local) {
        if (nodeKind == Type.ELEMENT) {
            for (Object o : ((Element) node).attributes()) {
                Attribute att = (Attribute) o;
                if (att.getName().equals(local) && att.getNamespaceURI().equals(uri)) {
                    return att.getValue();
                }
            }
        }
        return null;
    }

    /**
    * Get the root node - always a document node with this tree implementation
    * @return the NodeInfo representing the containing document
    */

    public NodeInfo getRoot() {
        return docWrapper;
    }

    /**
    * Get the root (document) node
    * @return the DocumentInfo representing the containing document
    */

    public DocumentInfo getDocumentRoot() {
        return docWrapper;
    }

    /**
    * Determine whether the node has any children. <br />
    * Note: the result is equivalent to <br />
    * getEnumeration(Axis.CHILD, AnyNodeTest.getInstance()).hasNext()
    */

    public boolean hasChildNodes() {
        switch (nodeKind) {
        case Type.DOCUMENT:
            return true;
        case Type.ELEMENT:
            // Beware: dom4j content() contains Namespace nodes (which is broken)!
            List content = ((Element) node).content();
            for (int i = 0; i < content.size(); i++) {
                if (!(content.get(i) instanceof Namespace)) {
                    return true;
                }
            }
            return false;
        default:
            return false;
        }
    }

    /**
    * Get a character string that uniquely identifies this node.
    * Note: a.isSameNode(b) if and only if generateId(a)==generateId(b)
    * @param buffer a Buffer to contain a string that uniquely identifies this node, across all
    * documents
     */

    public void generateId(FastStringBuffer buffer) {
        Navigator.appendSequentialKey(this, buffer, true);
        //buffer.append(Navigator.getSequentialKey(this));
    }

    /**
     * Get the document number of the document containing this node. For a free-standing
     * orphan node, just return the hashcode.
     */

    public long getDocumentNumber() {
        return getParent().getDocumentNumber();
    }

    /**
    * Copy this node to a given outputter (deep copy)
    */

    public void copy(Receiver out, int copyOptions, int locationId) throws XPathException {
        Navigator.copy(this, out, copyOptions, locationId);
    }

    /**
     * Determine whether this node has the is-id property
     *
     * @return true if the node is an ID.
     * For DOM4J, this always returns false, because no information about attribute types is available.
     */

    public boolean isId() {
        return false;
    }

    /**
     * Determine whether this node has the is-idref property
     *
     * @return true if the node is an IDREF or IDREFS element or attribute.
     * For DOM4J, this always returns false, because no information about attribute types is available.
     */

    public boolean isIdref() {
        return false;
    }

    /**
     * Determine whether the node has the is-nilled property
     *
     * @return true if the node has the is-nilled property. For DOM4J, this always returns false
     */

    public boolean isNilled() {
        return false;
    }

    ///////////////////////////////////////////////////////////////////////////////
    // Axis enumeration classes
    ///////////////////////////////////////////////////////////////////////////////

    private final class AttributeEnumeration extends Navigator.BaseEnumeration {

        private Iterator atts;
        private int ix = 0;
        private NodeWrapper start;

        public AttributeEnumeration(NodeWrapper start) {
            this.start = start;
            atts = ((Element) start.node).attributes().iterator();
        }

        public void advance() {
            if (atts.hasNext()) {
                current = makeWrapper(atts.next(), docWrapper, start, ix++);
            } else {
                current = null;
            }
        }

        /*@NotNull*/
        public AxisIterator getAnother() {
            return new AttributeEnumeration(start);
        }

    } // end of class AttributeEnumeration

    /**
    * The class ChildEnumeration handles not only the child axis, but also the
    * following-sibling and preceding-sibling axes. It can also iterate the children
    * of the start node in reverse order, something that is needed to support the
    * preceding and preceding-or-ancestor axes (the latter being used by xsl:number)
    */

    private final class ChildEnumeration extends Navigator.BaseEnumeration {

        private NodeWrapper start;
        private NodeWrapper commonParent;
        private ListIterator children;
        private int ix = 0;
        private boolean downwards; // iterate children of start node (not siblings)
        private boolean forwards; // iterate in document order (not reverse order)

        public ChildEnumeration(NodeWrapper start, boolean downwards, boolean forwards) {
            this.start = start;
            this.downwards = downwards;
            this.forwards = forwards;

            if (downwards) {
                commonParent = start;
            } else {
                commonParent = (NodeWrapper) start.getParent();
            }

            if (commonParent.getNodeKind() == Type.DOCUMENT) {
                children = ((Document) commonParent.node).content().listIterator();
            } else {
                children = ((Element) commonParent.node).content().listIterator();
            }

            if (downwards) {
                if (!forwards) {
                    // backwards enumeration: go to the end
                    while (children.hasNext()) {
                        children.next();
                        ix++;
                    }
                }
            } else {
                ix = start.getSiblingPosition();
                // find the start node among the list of siblings
                if (forwards) {
                    for (int i = 0; i <= ix; i++) {
                        children.next();
                    }
                    ix++;
                } else {
                    for (int i = 0; i < ix; i++) {
                        children.next();
                    }
                    ix--;
                }
            }
        }

        public void advance() {
            if (forwards) {
                if (children.hasNext()) {
                    Object nextChild = children.next();
                    if (nextChild instanceof DocumentType || nextChild instanceof Namespace) {
                        ix++; // increment anyway so that makeWrapper() passes the correct index)
                        advance();
                        return;
                    }
                    if (nextChild instanceof Entity) {
                        throw new IllegalStateException("Unexpanded entity in DOM4J tree");
                    } else {
                        current = makeWrapper(nextChild, docWrapper, commonParent, ix++);
                    }
                } else {
                    current = null;
                }
            } else { // backwards
                if (children.hasPrevious()) {
                    Object nextChild = children.previous();
                    if (nextChild instanceof DocumentType || nextChild instanceof Namespace) {
                        ix--; // decrement anyway so that makeWrapper() passes the correct index)
                        advance();
                        return;
                    }
                    if (nextChild instanceof Entity) {
                        throw new IllegalStateException("Unexpanded entity in DOM4J tree");
                    } else {
                        current = makeWrapper(nextChild, docWrapper, commonParent, ix--);
                    }
                } else {
                    current = null;
                }
            }
        }

        /*@NotNull*/
        public AxisIterator getAnother() {
            return new ChildEnumeration(start, downwards, forwards);
        }

    } // end of class ChildEnumeration

    /**
     * Determine whether this is the same node as another node.
     * Note: a.isSameNodeInfo(b) if and only if generateId(a)==generateId(b).
     * This method has the same semantics as isSameNode() in DOM Level 3, but
     * works on Saxon NodeInfo objects rather than DOM Node objects.
     *
     * @param other the node to be compared with this node
     * @return true if this NodeInfo object and the supplied NodeInfo object represent
     *         the same node in the tree.
     */

    public boolean isSameNodeInfo(NodeInfo other) {
        if (!(other instanceof NodeWrapper)) {
            return false;
        }
        NodeWrapper ow = (NodeWrapper) other;
        if (node instanceof Namespace) {
            return getLocalPart().equals(ow.getLocalPart()) && getParent().isSameNodeInfo(ow.getParent());
        }
        return node.equals(ow.node);
    }

    public Configuration getConfiguration() {
        return docWrapper.getConfiguration();
    }

    /**
     * Get all namespace undeclarations and undeclarations defined on this element.
     *
     * @param buffer If this is non-null, and the result array fits in this buffer, then the result
     *               may overwrite the contents of this array, to avoid the cost of allocating a new array on the heap.
     * @return An array of integers representing the namespace declarations and undeclarations present on
     *         this element. For a node other than an element, return null. Otherwise, the returned array is a
     *         sequence of namespace codes, whose meaning may be interpreted by reference to the name pool. The
     *         top half word of each namespace code represents the prefix, the bottom half represents the URI.
     *         If the bottom half is zero, then this is a namespace undeclaration rather than a declaration.
     *         The XML namespace is never included in the list. If the supplied array is larger than required,
     *         then the first unused entry will be set to -1.
     *         <p/>
     *         <p>For a node other than an element, the method returns null.</p>
     */
    public NamespaceBinding[] getDeclaredNamespaces(NamespaceBinding[] buffer) {
        if (node instanceof Element) {
            final Element elem = (Element) node;
            final List namespaces = elem.declaredNamespaces();

            if (namespaces == null || namespaces.isEmpty()) {
                return NamespaceBinding.EMPTY_ARRAY;
            }
            final int count = namespaces.size();
            if (count == 0) {
                return NamespaceBinding.EMPTY_ARRAY;
            } else {
                NamespaceBinding[] result = (buffer == null || count > buffer.length ? new NamespaceBinding[count]
                        : buffer);
                int n = 0;
                for (Iterator i = namespaces.iterator(); i.hasNext();) {
                    final Namespace namespace = (Namespace) i.next();
                    final String prefix = namespace.getPrefix();
                    final String uri = namespace.getURI();

                    result[n++] = new NamespaceBinding(prefix, uri);
                }
                if (count < result.length) {
                    result[count] = null;
                }
                return result;
            }
        } else {
            return null;
        }
    }

}

//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
// you may not use this file except in compliance with the License. You may obtain a copy of the
// License at http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file
//
// The Initial Developer of the Original Code is Saxonica Limited.
// Portions created by ___ are Copyright (C) ___. All rights reserved.
//
// Contributor(s):
//