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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2018-2023 Saxonica Limited
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.dom;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.expr.sort.CodepointCollator;
import net.sf.saxon.expr.sort.GenericAtomicComparer;
import net.sf.saxon.functions.DeepEqual;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.om.AxisInfo;
import net.sf.saxon.om.NodeInfo;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.tree.iter.AxisIterator;
import net.sf.saxon.tree.iter.SingletonIterator;
import net.sf.saxon.type.Type;
import org.w3c.dom.*;
import java.util.ArrayList;
import java.util.List;
/**
* This class implements the DOM Node interface as a wrapper around a Saxon NodeInfo object.
* The class provides read-only access to the tree; methods that request updates all fail
* with an UnsupportedOperationException.
*/
public abstract class NodeOverNodeInfo implements Node {
protected NodeInfo node;
/**
* Get the Saxon NodeInfo object representing this node
*
* @return the Saxon NodeInfo object
*/
/*@Nullable*/
public NodeInfo getUnderlyingNodeInfo() {
return node;
}
/**
* Factory method to construct a DOM node that wraps an underlying Saxon NodeInfo
*
* @param node the Saxon NodeInfo object
* @return the DOM wrapper node
*/
public static NodeOverNodeInfo wrap(NodeInfo node) {
NodeOverNodeInfo n;
if (node == null) {
return null;
}
switch (node.getNodeKind()) {
case Type.DOCUMENT:
n = new DocumentOverNodeInfo();
break;
case Type.ELEMENT:
n = new ElementOverNodeInfo();
break;
case Type.ATTRIBUTE:
n = new AttrOverNodeInfo();
break;
case Type.TEXT:
case Type.COMMENT:
n = new TextOverNodeInfo();
break;
case Type.PROCESSING_INSTRUCTION:
n = new PIOverNodeInfo();
break;
case Type.NAMESPACE:
n = new AttrOverNodeInfo();
break;
default:
return null;
}
n.node = node;
return n;
}
/**
* Determine whether this is the same node as another node. DOM Level 3 method.
*
* @return true if this Node object and the supplied Node object represent the
* same node in the tree.
*/
@Override
public final boolean isSameNode(Node other) {
return other instanceof NodeOverNodeInfo &&
node.equals(((NodeOverNodeInfo) other).node);
}
/**
* The equals() method returns true for two Node objects that represent the same
* conceptual DOM Node. This is a concession to the Xalan IdentityTransformer, which relies
* on equals() for DOM Nodes having this behaviour, even though it is not defined in the
* specification
*
* @param obj the object to be compared
* @return if this node and obj represent the same conceptual DOM node. That is, return
* true if isSameNode((Node)obj) returns true
*/
@Override
public boolean equals(Object obj) {
return obj instanceof Node && isSameNode((Node) obj);
}
/**
* Return a hashCode
*
* @return a hashCode such that two wrappers over the same underlying node have the same hashCode.
*/
@Override
public int hashCode() {
return node.hashCode();
}
/**
* Get the base URI for the node. Default implementation for child nodes gets
* the base URI of the parent node.
*/
@Override
public String getBaseURI() {
return node.getBaseURI();
}
/**
* Get the name of this node, following the DOM rules
*
* @return The name of the node. For an element this is the element name, for an attribute
* it is the attribute name, as a lexical QName. Other node types return conventional names such
* as "#text" or "#comment"
*/
@Override
public String getNodeName() {
switch (node.getNodeKind()) {
case Type.DOCUMENT:
return "#document";
case Type.ELEMENT:
return node.getDisplayName();
case Type.ATTRIBUTE:
return node.getDisplayName();
case Type.TEXT:
return "#text";
case Type.COMMENT:
return "#comment";
case Type.PROCESSING_INSTRUCTION:
return node.getLocalPart();
case Type.NAMESPACE:
if (node.getLocalPart().isEmpty()) {
return "xmlns";
} else {
return "xmlns:" + node.getLocalPart();
}
default:
return "#unknown";
}
}
/**
* Get the local name of this node, following the DOM rules
*
* @return The local name of the node. For an element this is the local part of the element name,
* for an attribute it is the local part of the attribute name. Other node types return null.
*/
@Override
public String getLocalName() {
switch (node.getNodeKind()) {
case Type.ELEMENT:
case Type.ATTRIBUTE:
return node.getLocalPart();
case Type.DOCUMENT:
case Type.TEXT:
case Type.COMMENT:
case Type.PROCESSING_INSTRUCTION:
return null;
case Type.NAMESPACE:
if (node.getLocalPart().isEmpty()) {
return "xmlns";
} else {
return node.getLocalPart();
}
default:
return null;
}
}
/**
* Determine whether the node has any children.
*
* @return true if this node has any attributes,
* false otherwise.
*/
@Override
public boolean hasChildNodes() {
return node.hasChildNodes();
}
/**
* Returns whether this node has any attributes. We treat the declaration of the XML namespace
* as being present on every element, and since namespace declarations are treated as attributes,
* every element has at least one attribute. This method therefore returns true.
*
* @return true if this node has any attributes,
* false otherwise.
* @since DOM Level 2
*/
@Override
public boolean hasAttributes() {
return true;
}
/**
* Get the type of this node (node kind, in XPath terminology).
* Note, the numbers assigned to node kinds
* in Saxon (see {@link Type}) are the same as those assigned in the DOM
*/
@Override
public short getNodeType() {
short kind = (short) node.getNodeKind();
if (kind == Type.NAMESPACE) {
return Type.ATTRIBUTE;
} else {
return kind;
}
}
/**
* Find the parent node of this node.
*
* @return The Node object describing the containing element or root node.
*/
@Override
public Node getParentNode() {
return wrap(node.getParent());
}
/**
* Get the previous sibling of the node
*
* @return The previous sibling node. Returns null if the current node is the first
* child of its parent.
*/
@Override
public Node getPreviousSibling() {
return wrap(node.iterateAxis(AxisInfo.PRECEDING_SIBLING).next());
}
/**
* Get next sibling node
*
* @return The next sibling node. Returns null if the current node is the last
* child of its parent.
*/
@Override
public Node getNextSibling() {
return wrap(node.iterateAxis(AxisInfo.FOLLOWING_SIBLING).next());
}
/**
* Get first child
*
* @return the first child node of this node, or null if it has no children
*/
@Override
public Node getFirstChild() {
return wrap(node.iterateAxis(AxisInfo.CHILD).next());
}
/**
* Get last child
*
* @return last child of this node, or null if it has no children
*/
@Override
public Node getLastChild() {
AxisIterator children = node.iterateAxis(AxisInfo.CHILD);
NodeInfo last = null;
while (true) {
NodeInfo next = children.next();
if (next == null) {
return wrap(last);
} else {
last = next;
}
}
}
/**
* Get the node value (as defined in the DOM).
* This is not generally the same as the XPath string-value: in particular, the
* node value of an element node is null.
*/
@Override
public String getNodeValue() {
switch (node.getNodeKind()) {
case Type.DOCUMENT:
case Type.ELEMENT:
return null;
case Type.ATTRIBUTE:
case Type.TEXT:
case Type.COMMENT:
case Type.PROCESSING_INSTRUCTION:
case Type.NAMESPACE:
return node.getStringValue();
default:
return null;
}
}
/**
* Set the node value. Always fails
*/
@Override
public void setNodeValue(String nodeValue) throws DOMException {
disallowUpdate();
}
/**
* Return a NodeList that contains all children of this node. If
* there are no children, this is a NodeList containing no
* nodes.
*/
@Override
public NodeList getChildNodes() {
List nodes = new ArrayList<>(10);
for (NodeInfo child : node.children()) {
nodes.add(NodeOverNodeInfo.wrap(child));
}
return new DOMNodeList(nodes);
}
/**
* Return a NamedNodeMap containing the attributes of this node (if
* it is an Element) or null otherwise.
*/
@Override
public NamedNodeMap getAttributes() {
return null;
}
/**
* Return the Document object associated with this node.
*/
@Override
public Document getOwnerDocument() {
return (Document) wrap(node.getRoot());
}
/**
* Insert the node newChild before the existing child node
* refChild. Always fails.
*
* @param newChild The node to insert.
* @param refChild The reference node, i.e., the node before which the
* new node must be inserted.
* @return The node being inserted.
* @throws org.w3c.dom.DOMException NO_MODIFICATION_ALLOWED_ERR: Always raised.
*/
@Override
public Node insertBefore(Node newChild,
Node refChild)
throws DOMException {
disallowUpdate();
return null;
}
/**
* Replace the child node oldChild with
* newChild in the list of children, and returns the
* oldChild node. Always fails.
*
* @param newChild The new node to put in the child list.
* @param oldChild The node being replaced in the list.
* @return The node replaced.
* @throws org.w3c.dom.DOMException NO_MODIFICATION_ALLOWED_ERR: Always raised.
*/
@Override
public Node replaceChild(Node newChild,
Node oldChild)
throws DOMException {
disallowUpdate();
return null;
}
/**
* Remove the child node indicated by oldChild from the
* list of children, and returns it. Always fails.
*
* @param oldChild The node being removed.
* @return The node removed.
* @throws org.w3c.dom.DOMException NO_MODIFICATION_ALLOWED_ERR: Always raised.
*/
@Override
public Node removeChild(Node oldChild) throws DOMException {
disallowUpdate();
return null;
}
/**
* Adds the node newChild to the end of the list of children
* of this node. Always fails.
*
* @param newChild The node to add.
* @return The node added.
* @throws org.w3c.dom.DOMException
NO_MODIFICATION_ALLOWED_ERR: Always raised.
*/
@Override
public Node appendChild(Node newChild) throws DOMException {
disallowUpdate();
return null;
}
/**
* Returns a duplicate of this node, i.e., serves as a generic copy
* constructor for nodes. Always fails.
*
* @param deep If true , recursively clone the subtree under
* the specified node; if false , clone only the node
* itself (and its attributes, if it is an Element ).
* @return The duplicate node.
*/
@Override
public Node cloneNode(boolean deep) {
disallowUpdate();
return null;
}
/**
* Puts all Text nodes in the full depth of the sub-tree
* underneath this Node, including attribute nodes, into a
* "normal" form where only structure (e.g., elements, comments,
* processing instructions, CDATA sections, and entity references)
* separates Text nodes, i.e., there are neither adjacent
* Text nodes nor empty Text nodes.
*
* @since DOM Level 2
*/
@Override
public void normalize() {
// null operation; nodes are always normalized
}
/**
* Tests whether the DOM implementation implements a specific feature and
* that feature is supported by this node.
*
* @param feature The name of the feature to test. This is the same name
* which can be passed to the method hasFeature on
* DOMImplementation .
* @param version This is the version number of the feature to test. In
* Level 2, version 1, this is the string "2.0". If the version is not
* specified, supporting any version of the feature will cause the
* method to return true .
* @return Returns true if the specified feature is supported
* on this node, false otherwise.
* @since DOM Level 2
*/
@Override
public boolean isSupported(String feature,
String version) {
return (feature.equalsIgnoreCase("XML") || feature.equalsIgnoreCase("Core")) &&
(version == null || version.isEmpty() ||
version.equals("3.0") || version.equals("2.0") || version.equals("1.0"));
}
/**
* The namespace URI of this node, or null if it is
* unspecified.
*
This is not a computed value that is the result of a namespace
* lookup based on an examination of the namespace declarations in scope.
* It is merely the namespace URI given at creation time.
*
For nodes of any type other than ELEMENT_NODE and
* ATTRIBUTE_NODE and nodes created with a DOM Level 1
* method, such as createElement from the
* Document interface, this is always null .
* Per the Namespaces in XML Specification an attribute does not
* inherit its namespace from the element it is attached to. If an
* attribute is not explicitly given a namespace, it simply has no
* namespace.
*
* @since DOM Level 2
*/
@Override
public String getNamespaceURI() {
if (node.getNodeKind() == Type.NAMESPACE) {
return NamespaceConstant.XMLNS;
}
String uri = node.getNamespaceUri().toString();
return "".equals(uri) ? null : uri;
}
/**
* The namespace prefix of this node, or null if it is
* unspecified.
*
For nodes of any type other than ELEMENT_NODE and
* ATTRIBUTE_NODE and nodes created with a DOM Level 1
* method, such as createElement from the
* Document interface, this is always null.
*
* @since DOM Level 2
*/
@Override
public String getPrefix() {
if (node.getNodeKind() == Type.NAMESPACE) {
if (node.getLocalPart().isEmpty()) {
return null;
} else {
return "xmlns";
}
}
String p = node.getPrefix();
return "".equals(p) ? null : p;
}
/**
* Set the namespace prefix of this node. Always fails.
*/
@Override
public void setPrefix(String prefix)
throws DOMException {
disallowUpdate();
}
/**
* Compare the position of the (other) node in document order with the reference node (this node).
* DOM Level 3 method.
*
* @param other the other node.
* @return Returns how the node is positioned relatively to the reference
* node.
* @throws org.w3c.dom.DOMException if an error occurs
*/
@Override
public short compareDocumentPosition(Node other) throws DOMException {
final short DOCUMENT_POSITION_DISCONNECTED = 0x01;
final short DOCUMENT_POSITION_PRECEDING = 0x02;
final short DOCUMENT_POSITION_FOLLOWING = 0x04;
final short DOCUMENT_POSITION_CONTAINS = 0x08;
final short DOCUMENT_POSITION_CONTAINED_BY = 0x10;
if (!(other instanceof NodeOverNodeInfo)) {
return DOCUMENT_POSITION_DISCONNECTED;
}
int c = node.compareOrder(((NodeOverNodeInfo) other).node);
if (c == 0) {
return (short) 0;
} else if (c == -1) {
short result = DOCUMENT_POSITION_FOLLOWING;
short d = compareDocumentPosition(other.getParentNode());
if (d == 0 || (d & DOCUMENT_POSITION_CONTAINED_BY) != 0) {
result |= DOCUMENT_POSITION_CONTAINED_BY;
}
return result;
} else if (c == +1) {
short result = DOCUMENT_POSITION_PRECEDING;
short d = getParentNode().compareDocumentPosition(other);
if (d == 0 || (d & DOCUMENT_POSITION_CONTAINS) != 0) {
result |= DOCUMENT_POSITION_CONTAINS;
}
return result;
} else {
throw new AssertionError();
}
}
/**
* Get the text content of a node. This is a DOM Level 3 method. The definition
* is the same as the definition of the string value of a node in XPath, except
* in the case of document nodes.
*
* @return the string value of the node, or null in the case of document nodes.
* @throws org.w3c.dom.DOMException if a dynamic error occurs
*/
@Override
public String getTextContent() throws DOMException {
if (node.getNodeKind() == Type.DOCUMENT) {
return null;
} else {
return node.getStringValue();
}
}
/**
* Set the text content of a node. Always fails.
*
* @param textContent the new text content of the node
* @throws UnsupportedOperationException always
*/
@Override
public void setTextContent(String textContent) throws UnsupportedOperationException {
disallowUpdate();
}
/**
* Get the (first) prefix assigned to a specified namespace URI, or null
* if the namespace is not in scope. DOM Level 3 method.
*
* @param namespaceURI the namespace whose prefix is required
* @return the corresponding prefix, if there is one, or null if not.
*/
@Override
public String lookupPrefix(String namespaceURI) {
if (node.getNodeKind() == Type.DOCUMENT) {
return null;
} else if (node.getNodeKind() == Type.ELEMENT) {
AxisIterator iter = node.iterateAxis(AxisInfo.NAMESPACE);
NodeInfo ns;
while ((ns = iter.next()) != null) {
if (ns.getUnicodeStringValue().equals(namespaceURI)) {
return ns.getLocalPart();
}
}
return null;
} else {
return getParentNode().lookupPrefix(namespaceURI);
}
}
/**
* Test whether a particular namespace is the default namespace.
* DOM Level 3 method.
*
* @param namespaceURI the namespace to be tested
* @return true if this is the default namespace
*/
@Override
public boolean isDefaultNamespace(String namespaceURI) {
return namespaceURI.equals(lookupNamespaceURI(""));
}
/**
* Find the URI corresponding to a given in-scope prefix
*
* @param prefix The namespace prefix whose namespace URI is required.
* @return the corresponding namespace URI, or null if the prefix is
* not declared.
*/
@Override
public String lookupNamespaceURI(String prefix) {
if (node.getNodeKind() == Type.DOCUMENT) {
return null;
} else if (node.getNodeKind() == Type.ELEMENT) {
AxisIterator iter = node.iterateAxis(AxisInfo.NAMESPACE);
NodeInfo ns;
while ((ns = iter.next()) != null) {
if (ns.getLocalPart().equals(prefix)) {
return ns.getStringValue();
}
}
return null;
} else {
return getParentNode().lookupNamespaceURI(prefix);
}
}
/**
* Compare whether two nodes have the same content. This is a DOM Level 3 method.
*
* @param arg The node to be compared. This must wrap a Saxon NodeInfo.
* @return true if the two nodes are deep-equal.
*/
@Override
public boolean isEqualNode(Node arg) {
if (!(arg instanceof NodeOverNodeInfo)) {
throw new IllegalArgumentException("Other Node must wrap a Saxon NodeInfo");
}
try {
XPathContext context = node.getConfiguration().getConversionContext();
return DeepEqual.deepEqual(
SingletonIterator.makeIterator(node),
SingletonIterator.makeIterator(((NodeOverNodeInfo) arg).node),
new GenericAtomicComparer(CodepointCollator.getInstance(),
context),
context,
DeepEqual.INCLUDE_PREFIXES |
DeepEqual.INCLUDE_COMMENTS |
DeepEqual.COMPARE_STRING_VALUES |
DeepEqual.INCLUDE_PROCESSING_INSTRUCTIONS);
} catch (XPathException err) {
// can't happen
return false;
}
}
/**
* Get a feature of this node. DOM Level 3 method, always returns null.
*
* @param feature the required feature
* @param version the version of the required feature
* @return the value of the feature. Always null in this implementation
*/
@Override
public Object getFeature(String feature, String version) {
return null;
}
/**
* Set user data. Always throws UnsupportedOperationException in this implementation
*
* @param key name of the user data
* @param data value of the user data
* @param handler handler for the user data
* @return This implementation always throws an exception
*/
@Override
public Object setUserData(String key, Object data, UserDataHandler handler) {
disallowUpdate();
return null;
}
/**
* Get user data associated with this node. DOM Level 3 method, always returns
* null in this implementation
*
* @param key identifies the user data required
* @return always null in this implementation
*/
@Override
public Object getUserData(String key) {
return null;
}
/**
* Internal method used to indicate that update operations are not allowed
*
* @throws org.w3c.dom.DOMException always, to indicate that update is not supported in this DOM implementation
*/
protected static void disallowUpdate() throws DOMException {
throw new org.w3c.dom.DOMException(
DOMException.NO_MODIFICATION_ALLOWED_ERR,
"The Saxon DOM implementation cannot be updated");
}
}