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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2018-2022 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.tree.wrapper;
import net.sf.saxon.event.Receiver;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.om.*;
import net.sf.saxon.pattern.AnyNodeTest;
import net.sf.saxon.pattern.NodePredicate;
import net.sf.saxon.pattern.NodeTest;
import net.sf.saxon.s9api.Location;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.transpile.CSharpModifiers;
import net.sf.saxon.tree.NamespaceNode;
import net.sf.saxon.tree.iter.AxisIterator;
import net.sf.saxon.tree.iter.EmptyIterator;
import net.sf.saxon.tree.util.Navigator;
import net.sf.saxon.type.Type;
import net.sf.saxon.value.StringValue;
/**
* A node in the XML parse tree representing an XML element, character content, or attribute.
* This implementation of the NodeInfo interface contains common code used by many "wrapper" implementations
* for external data models.
*
*/
public abstract class AbstractNodeWrapper implements NodeInfo, VirtualNode {
protected TreeInfo treeInfo;
@Override
public TreeInfo getTreeInfo() {
return treeInfo;
}
/**
* 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.
*/
@Override
public final Object getRealNode() {
return getUnderlyingNode();
}
/**
* Get the name pool for this node
*
* @return the NamePool
*/
public NamePool getNamePool() {
return getConfiguration().getNamePool();
}
/**
* Get the typed value.
*
* @return the typed value. This will either be a single AtomicValue or a value whose items are
* atomic values.
* @since 8.5 - signature changed in 9.5
*/
@Override
public AtomicSequence atomize() throws XPathException {
switch (getNodeKind()) {
case Type.COMMENT:
case Type.PROCESSING_INSTRUCTION:
return new StringValue(getUnicodeStringValue());
default:
return StringValue.makeUntypedAtomic(getUnicodeStringValue());
}
}
/**
* The equals() method compares nodes for identity. It is defined to give the same result
* as isSameNodeInfo().
*
* @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.
* @since 8.7 Previously, the effect of the equals() method was not defined. Callers
* should therefore be aware that third party implementations of the NodeInfo interface may
* not implement the correct semantics. It is safer to use isSameNodeInfo() for this reason.
* The equals() method has been defined because it is useful in contexts such as a Java Set or HashMap.
*/
public boolean equals(Object other) {
if (!(other instanceof AbstractNodeWrapper)) {
return false;
}
AbstractNodeWrapper ow = (AbstractNodeWrapper) other;
return getUnderlyingNode().equals(ow.getUnderlyingNode());
}
/**
* The hashCode() method obeys the contract for hashCode(): that is, if two objects are equal
* (represent the same node) then they must have the same hashCode()
*
* @since 8.7 Previously, the effect of the equals() and hashCode() methods was not defined. Callers
* should therefore be aware that third party implementations of the NodeInfo interface may
* not implement the correct semantics.
*/
public int hashCode() {
return getUnderlyingNode().hashCode();
}
/**
* 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.
*/
@Override
@CSharpModifiers(code={"public", "virtual"})
public String getSystemId() {
if (treeInfo instanceof GenericTreeInfo) {
return ((GenericTreeInfo)treeInfo).getSystemId();
} else {
throw new UnsupportedOperationException();
// must implement in subclass
}
}
/**
* Set the system ID. Required because NodeInfo implements the JAXP Source interface
* @param uri the system ID.
*/
@Override
public void setSystemId(String uri) {
throw new UnsupportedOperationException();
}
/**
* Get the Base URI for the node, that is, the URI used for resolving a relative URI contained
* in the node.
*
* @return the base URI of the node, taking into account xml:base attributes if present
*/
@Override
@CSharpModifiers(code={"public virtual"})
public String getBaseURI() {
if (getNodeKind() == Type.NAMESPACE) {
return null;
}
NodeInfo n = this;
if (getNodeKind() != Type.ELEMENT) {
n = getParent();
}
// Look for an xml:base attribute
while (n != null) {
String xmlbase = n.getAttributeValue(NamespaceConstant.XML, "base");
if (xmlbase != null) {
return xmlbase;
}
n = n.getParent();
}
// if not found, return the base URI of the document node
return getRoot().getSystemId();
}
/**
* Get line number
*
* @return the line number of the node in its original source document; or -1 if not available.
* Always returns -1 in this implementation.
*/
@Override
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
*/
@Override
public int getColumnNumber() {
return -1;
}
/**
* Get an immutable copy of this Location object. By default Location objects may be mutable, so they
* should not be saved for later use. The result of this operation holds the same location information,
* but in an immutable form.
*/
@Override
public Location saveLocation() {
return this;
}
/**
* 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.
*/
@Override
@CSharpModifiers(code={"public", "virtual"})
public String getDisplayName() {
String prefix = getPrefix();
String local = getLocalPart();
if (prefix.isEmpty()) {
return local;
} else {
return prefix + ":" + local;
}
}
/**
* Get the string value of a given attribute of this node.
* The default implementation is suitable for nodes other than elements.
*
* @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
*/
@Override
@CSharpModifiers(code = {"public", "virtual"})
public String getAttributeValue(String uri, String local) {
return null;
}
/**
* 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.
*/
@Override
@CSharpModifiers(code={"public", "virtual"})
public AxisIterator iterateAxis(int axisNumber) {
return iterateAxis(axisNumber, AnyNodeTest.getInstance());
}
/**
* Return an iteration over the nodes reached by the given axis from this node.
* This superclass provides implementations of the ancestor, ancestor-or-self,
* following, namespace, parent, preceding, self, and preceding-or-ancestor axes.
* The other axes are implemented by calling methods iterateAttributes(),
* iterateChildren(), iterateDescendants(), and iterateSiblings(), which must
* be provided in a subclass.
*
* @param axisNumber the axis to be used
* @param predicate A pattern to be matched by the returned nodes
* @return a SequenceIterator that scans the nodes reached by the axis in turn.
*/
@Override
@CSharpModifiers(code = {"public", "virtual"})
public AxisIterator iterateAxis(int axisNumber, NodePredicate predicate) {
NodeTest nodeTest = Navigator.nodeTestFromPredicate(predicate);
int nodeKind = getNodeKind();
switch (axisNumber) {
case AxisInfo.ANCESTOR:
if (nodeKind == Type.DOCUMENT) {
return EmptyIterator.ofNodes();
}
return new Navigator.AxisFilter(
new Navigator.AncestorEnumeration(this, false),
nodeTest);
case AxisInfo.ANCESTOR_OR_SELF:
if (nodeKind == Type.DOCUMENT) {
return Navigator.filteredSingleton(this, nodeTest);
}
return new Navigator.AxisFilter(
new Navigator.AncestorEnumeration(this, true),
nodeTest);
case AxisInfo.ATTRIBUTE:
if (nodeKind != Type.ELEMENT) {
return EmptyIterator.ofNodes();
}
return iterateAttributes(nodeTest);
case AxisInfo.CHILD:
if (nodeKind == Type.ELEMENT || nodeKind == Type.DOCUMENT) {
return iterateChildren(nodeTest);
} else {
return EmptyIterator.ofNodes();
}
case AxisInfo.DESCENDANT:
if (nodeKind == Type.ELEMENT || nodeKind == Type.DOCUMENT) {
return iterateDescendants(nodeTest, false);
} else {
return EmptyIterator.ofNodes();
}
case AxisInfo.DESCENDANT_OR_SELF:
if (nodeKind == Type.ELEMENT || nodeKind == Type.DOCUMENT) {
return iterateDescendants(nodeTest, true);
} else {
return Navigator.filteredSingleton(this, nodeTest);
}
case AxisInfo.FOLLOWING:
return new Navigator.AxisFilter(
new Navigator.FollowingEnumeration(this),
nodeTest);
case AxisInfo.FOLLOWING_SIBLING:
switch (nodeKind) {
case Type.DOCUMENT:
case Type.ATTRIBUTE:
case Type.NAMESPACE:
return EmptyIterator.ofNodes();
default:
return iterateSiblings(nodeTest, true);
}
case AxisInfo.NAMESPACE:
if (nodeKind != Type.ELEMENT) {
return EmptyIterator.ofNodes();
}
return NamespaceNode.makeIterator(this, nodeTest);
case AxisInfo.PARENT:
return Navigator.filteredSingleton(getParent(), nodeTest);
case AxisInfo.PRECEDING:
return new Navigator.AxisFilter(
new Navigator.PrecedingEnumeration(this, false),
nodeTest);
case AxisInfo.PRECEDING_SIBLING:
switch (nodeKind) {
case Type.DOCUMENT:
case Type.ATTRIBUTE:
case Type.NAMESPACE:
return EmptyIterator.ofNodes();
default:
return iterateSiblings(nodeTest, false);
}
case AxisInfo.SELF:
return Navigator.filteredSingleton(this, nodeTest);
case AxisInfo.PRECEDING_OR_ANCESTOR:
return new Navigator.AxisFilter(
new Navigator.PrecedingEnumeration(this, true),
nodeTest);
default:
throw new IllegalArgumentException("Unknown axis number " + axisNumber);
}
}
/**
* Return an iterator over the attributes of this element node.
* This method is only called after checking that the node is an element.
*
* @param nodeTest a test that the returned attributes must satisfy
* @return an iterator over the attribute nodes. The order of the result,
* although arbitrary, must be consistent with document order.
*/
protected abstract AxisIterator iterateAttributes(NodeTest nodeTest);
/**
* Return an iterator over the children of this node.
* This method is only called after checking that the node is an element or document.
*
* @param nodeTest a test that the returned attributes must satisfy
* @return an iterator over the child nodes, in document order.
*/
protected abstract AxisIterator iterateChildren(NodeTest nodeTest);
/**
* Return an iterator over the siblings of this node.
* This method is only called after checking that the node is an element, text, comment, or PI node.
*
* @param nodeTest a test that the returned siblings must satisfy
* @param forwards true for following siblings, false for preceding siblings
* @return an iterator over the sibling nodes, in axis order.
*/
protected abstract AxisIterator iterateSiblings(NodeTest nodeTest, boolean forwards);
/**
* Return an iterator over the descendants of this node.
* This method is only called after checking that the node is an element or document node.
*
* @param nodeTest a test that the returned descendants must satisfy
* @param includeSelf true if this node is to be included in the result
* @return an iterator over the sibling nodes, in axis order.
*/
@CSharpModifiers(code={"protected", "virtual"})
protected AxisIterator iterateDescendants(NodeTest nodeTest, boolean includeSelf) {
AxisIterator iter = new Navigator.DescendantEnumeration(this, includeSelf, true);
if (!(nodeTest instanceof AnyNodeTest)) {
iter = new Navigator.AxisFilter(iter, nodeTest);
}
return iter;
}
/**
* Get all namespace declarations and undeclarations defined on this element.
* This method is intended primarily for internal use. User applications needing
* information about the namespace context of a node should use iterateAxis(Axis.NAMESPACE).
* (However, not all implementations support the namespace axis, whereas all implementations are
* required to support this method.)
* This implementation of the method is suitable for all nodes other than elements; it returns
* an empty array.
*
* @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 namespace binding objects representing the namespace declarations and undeclarations present on
* this element. For a node other than an element, return null.
* If the uri part is "", 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 null.
* For a node other than an element, the method returns null.
*/
@Override
@CSharpModifiers(code = {"public", "virtual"})
public NamespaceBinding[] getDeclaredNamespaces(NamespaceBinding[] buffer) {
return new NamespaceBinding[0];
}
/**
* Get all the namespace bindings that are in-scope for this element.
* For an element return all the prefix-to-uri bindings that are in scope. This may include
* a binding to the default namespace (represented by a prefix of ""). It will never include
* "undeclarations" - that is, the namespace URI will never be empty; the effect of an undeclaration
* is to remove a binding from the in-scope namespaces, not to add anything.
* For a node other than an element, returns null.
*
* @return the in-scope namespaces for an element, or null for any other kind of node.
*/
@Override
@CSharpModifiers(code={"public", "virtual"})
public NamespaceMap getAllNamespaces() {
if (getNodeKind() == Type.ELEMENT) {
throw new AssertionError("getAllNamespaces() not implemented for " + getClass());
}
return null;
}
/**
* Get the root node - always a document node with this tree implementation
*
* @return the NodeInfo representing the containing document
*/
@Override
public NodeInfo getRoot() {
NodeInfo p = this;
while (true) {
NodeInfo q = p.getParent();
if (q==null) {
return p;
}
p = q;
}
}
/**
* Determine whether the node has any children.
* This implementation calls iterateAxis, so the subclass implementation of iterateAxis
* must avoid calling this method.
*/
@Override
@CSharpModifiers(code = {"public", "virtual"})
public boolean hasChildNodes() {
switch (getNodeKind()) {
case Type.DOCUMENT:
case Type.ELEMENT:
return iterateAxis(AxisInfo.CHILD).next() != null;
default:
return false;
}
}
/**
* Get the fingerprint of the node
*
* @return the node's fingerprint, or -1 for an unnamed node
* @throws UnsupportedOperationException if this method is called for a node where
* hasFingerprint() returns false;
*/
@Override
@CSharpModifiers(code = {"public", "virtual"})
public int getFingerprint() {
throw new UnsupportedOperationException();
}
/**
* Test whether a fingerprint is available for the node name
*/
@Override
@CSharpModifiers(code = {"public", "virtual"})
public boolean hasFingerprint() {
return false;
}
}