net.sf.saxon.tree.wrapper.VirtualCopy Maven / Gradle / Ivy
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2013 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.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.iter.AxisIterator;
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.type.SchemaType;
import net.sf.saxon.type.Type;
import javax.xml.transform.SourceLocator;
/**
* This class represents a node that is a virtual copy of another node: that is, it behaves as a node that's the
* same as another node, but has different identity. Moreover, this class can create a virtual copy of a subtree,
* so that the parent of the virtual copy is null rather than being a virtual copy of the parent of the original.
* This means that none of the axes when applied to the virtual copy is allowed to stray outside the subtree.
* The virtual copy is implemented by means of a reference to the node of which
* it is a copy, but methods that are sensitive to node identity return a different result.
*/
public class VirtualCopy implements NodeInfo, SourceLocator {
protected String systemId;
protected long documentNumber;
protected NodeInfo original;
protected VirtualCopy parent;
protected NodeInfo root; // the node forming the root of the subtree that was copied
/**
* Protected constructor: create a virtual copy of a node
*
* @param base the node to be copied
*/
protected VirtualCopy(/*@NotNull*/ NodeInfo base) {
original = base;
systemId = base.getBaseURI();
}
/**
* Public factory method: create a virtual copy of a node
*
* @param original the node to be copied
* @param root the root of the tree containing the node to be copied
* @return the virtual copy. If the original was already a virtual copy, this will be a virtual copy
* of the real underlying node.
*/
public static VirtualCopy makeVirtualCopy(NodeInfo original, NodeInfo root) {
VirtualCopy vc;
// Don't allow copies of copies of copies: define the new copy in terms of the original
while (original instanceof VirtualCopy) {
original = ((VirtualCopy) original).original;
}
while (root instanceof VirtualCopy) {
root = ((VirtualCopy) root).original;
}
if (original.getNodeKind() == Type.DOCUMENT) {
vc = new VirtualDocumentCopy((DocumentInfo) original);
} else {
vc = new VirtualCopy(original);
}
vc.root = root;
return vc;
}
/**
* Wrap a node in a VirtualCopy.
*
* @param node the node to be wrapped
* @return a virtual copy of the node
*/
/*@NotNull*/
protected VirtualCopy wrap(/*@NotNull*/ NodeInfo node) {
return new VirtualCopy(node);
}
/**
* To implement {@link Sequence}, this method returns the item itself
* @return this item
*/
public Item head() {
return this;
}
/**
* To implement {@link Sequence}, this method returns a singleton iterator
* that delivers this item in the form of a sequence
* @return a singleton iterator that returns this item
*/
public SequenceIterator iterate() {
return SingletonIterator.makeIterator(this);
}
/**
* Set the unique document number of the virtual document. This method must be called to ensure
* that nodes in the virtual copy have unique node identifiers
*
* @param documentNumber the document number to be allocated. This can be obtained from the
* {@link net.sf.saxon.tree.util.DocumentNumberAllocator} which is accessible from the Configuration using
* {@link net.sf.saxon.Configuration#getDocumentNumberAllocator()}
*/
public void setDocumentNumber(long documentNumber) {
this.documentNumber = documentNumber;
}
/**
* Get the kind of node. This will be a value such as Type.ELEMENT or Type.ATTRIBUTE
*
* @return an integer identifying the kind of node. These integer values are the
* same as those used in the DOM
* @see net.sf.saxon.type.Type
*/
public int getNodeKind() {
return original.getNodeKind();
}
/**
* 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(/*@NotNull*/ NodeInfo other) {
return other instanceof VirtualCopy &&
documentNumber == other.getDocumentNumber() &&
original.isSameNodeInfo(((VirtualCopy) other).original);
}
/**
* 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) {
return other instanceof NodeInfo && isSameNodeInfo((NodeInfo) other);
}
/**
* 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 original.hashCode() ^ ((int) (documentNumber & 0x7fffffff) << 19);
}
/**
* 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 systemId;
}
/**
* Get the Base URI for the node, that is, the URI used for resolving a relative URI contained
* in the node. This will be the same as the System ID unless xml:base has been used.
*
* @return the base URI of the node
*/
/*@Nullable*/
public String getBaseURI() {
return Navigator.getBaseURI(this);
}
/**
* Get line number
*
* @return the line number of the node in its original source document; or
* -1 if not available
*/
public int getLineNumber() {
return original.getLineNumber();
}
/**
* Get column number
*
* @return the column number of the node in its original source document; or -1 if not available
*/
public int getColumnNumber() {
return original.getColumnNumber();
}
/**
* 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(/*@NotNull*/ NodeInfo other) {
return original.compareOrder(((VirtualCopy) other).original);
}
/**
* Determine the relative position of this node and another node, in document order,
* distinguishing whether the first node is a preceding, following, descendant, ancestor,
* or the same node as the second.
*
* The other node must always be in the same tree; the effect of calling this method
* when the two nodes are in different trees is undefined. If either node is a namespace
* or attribute node, the method should throw UnsupportedOperationException.
*
* @param other The other node, whose position is to be compared with this
* node
* @return {@link net.sf.saxon.om.AxisInfo#PRECEDING} if this node is on the preceding axis of the other node;
* {@link net.sf.saxon.om.AxisInfo#FOLLOWING} if it is on the following axis; {@link net.sf.saxon.om.AxisInfo#ANCESTOR} if the first node is an
* ancestor of the second; {@link net.sf.saxon.om.AxisInfo#DESCENDANT} if the first is a descendant of the second;
* {@link net.sf.saxon.om.AxisInfo#SELF} if they are the same node.
* @throws UnsupportedOperationException if either node is an attribute or namespace
* @since 9.5
*/
public int comparePosition(NodeInfo other) {
return original.comparePosition(((VirtualCopy) other).original);
}
/**
* 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 original.getStringValue();
}
/**
* Get the value of the item as a CharSequence. This is in some cases more efficient than
* the version of the method that returns a String.
*/
public CharSequence getStringValueCS() {
return original.getStringValueCS();
}
/**
* 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.
*
* @return an integer name code, which may be used to obtain the actual node
* name from the name pool
* @see net.sf.saxon.om.NamePool#allocate allocate
* @see net.sf.saxon.om.NamePool#getFingerprint getFingerprint
*/
public int getNameCode() {
return original.getNameCode();
}
/**
* 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.
*
* @return an integer fingerprint; two nodes with the same fingerprint have
* the same expanded QName
*/
public int getFingerprint() {
return original.getFingerprint();
}
/**
* 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 "". Unlike the DOM
* interface, this returns the full name in the case of a non-namespaced name.
*/
public String getLocalPart() {
return original.getLocalPart();
}
/**
* 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,
* or for a node with an empty prefix, return an empty
* string.
*/
public String getURI() {
return original.getURI();
}
/**
* Get the prefix of the name of the node. This is defined only for elements and attributes.
* If the node has no prefix, or for other kinds of node, return a zero-length string.
*
* @return The prefix of the name of the node.
*/
public String getPrefix() {
return original.getPrefix();
}
/**
* 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() {
return original.getDisplayName();
}
/**
* Get the configuration
*/
public Configuration getConfiguration() {
return original.getConfiguration();
}
/**
* Get the NamePool that holds the namecode for this node
*
* @return the namepool
*/
public NamePool getNamePool() {
return original.getNamePool();
}
/**
* Get the type annotation of this node, if any.
*
* @return the type annotation of the node.
* @see net.sf.saxon.type.Type
*/
public int getTypeAnnotation() {
return original.getTypeAnnotation();
}
/**
* Get the type annotation of this node, if any. The type annotation is represented as
* SchemaType object.
*
* Types derived from a DTD are not reflected in the result of this method.
*
* @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() {
return original.getSchemaType();
}
/**
* Get the NodeInfo object representing the parent of this node
*
* @return the parent of this node; null if this node has no parent
*/
/*@Nullable*/
public NodeInfo getParent() {
if (original.isSameNodeInfo(root)) {
return null;
}
if (parent == null) {
NodeInfo basep = original.getParent();
if (basep == null) {
return null;
}
parent = wrap(basep);
parent.setDocumentNumber(documentNumber);
}
return parent;
}
/**
* Return an iteration over all the nodes reached by the given axis from this node
*
* @param axisNumber an integer identifying the axis; one of the constants
* defined in class net.sf.saxon.om.Axis
* @return an AxisIterator that scans the nodes reached by the axis in
* turn.
* @throws UnsupportedOperationException if the namespace axis is
* requested and this axis is not supported for this implementation.
* @see net.sf.saxon.om.AxisInfo
*/
public AxisIterator iterateAxis(byte axisNumber) {
return iterateAxis(axisNumber, AnyNodeTest.getInstance());
}
/**
* Return an iteration over all the nodes reached by the given axis from this node
* that match a given NodeTest
*
* @param axisNumber an integer identifying the axis; one of the constants
* defined in class net.sf.saxon.om.Axis
* @param nodeTest A pattern to be matched by the returned nodes; nodes
* that do not match this pattern are not included in the result
* @return an AxisIterator that scans the nodes reached by the axis in
* turn.
* @throws UnsupportedOperationException if the namespace axis is
* requested and this axis is not supported for this implementation.
* @see net.sf.saxon.om.AxisInfo
*/
public AxisIterator iterateAxis(byte axisNumber, NodeTest nodeTest) {
VirtualCopy newParent = null;
if (axisNumber == AxisInfo.CHILD || axisNumber == AxisInfo.ATTRIBUTE || axisNumber == AxisInfo.NAMESPACE) {
newParent = this;
} else if (axisNumber == AxisInfo.SELF || axisNumber == AxisInfo.PRECEDING_SIBLING || axisNumber == AxisInfo.FOLLOWING_SIBLING) {
newParent = parent;
}
NodeInfo root;
if (AxisInfo.isSubtreeAxis[axisNumber]) {
root = null;
} else {
root = this.root;
}
return makeCopier(original.iterateAxis(axisNumber, nodeTest), newParent, root);
}
/**
* 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.
*/
public String getAttributeValue(/*@NotNull*/ String uri, /*@NotNull*/ String local) {
return original.getAttributeValue(uri, local);
}
/**
* Get the root node of the tree containing this node
*
* @return the NodeInfo representing the top-level ancestor of this node.
* This will not necessarily be a document node
*/
/*@Nullable*/
public NodeInfo getRoot() {
NodeInfo n = this;
while (true) {
NodeInfo p = n.getParent();
if (p == null) {
return n;
}
n = p;
}
}
/**
* Get the root node, if it is a document node.
*
* @return the DocumentInfo representing the containing document. If this
* node is part of a tree that does not have a document node as its
* root, return null.
*/
/*@Nullable*/
public DocumentInfo getDocumentRoot() {
NodeInfo root = getRoot();
if (root.getNodeKind() == Type.DOCUMENT) {
return (DocumentInfo) root;
}
return null;
}
/**
* Determine whether the node has any children.
* Note: the result is equivalent to
* getEnumeration(Axis.CHILD, AnyNodeTest.getInstance()).hasNext()
*
* @return True if the node has one or more children
*/
public boolean hasChildNodes() {
return original.hasChildNodes();
}
/**
* 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 which will be appended
* a string that uniquely identifies this node, across all
* documents.
*/
public void generateId(/*@NotNull*/ FastStringBuffer buffer) {
buffer.append("d");
buffer.append(Long.toString(documentNumber));
original.generateId(buffer);
}
/**
* Get the document number of the document containing this node. For a free-standing
* orphan node, just return the hashcode.
*/
public long getDocumentNumber() {
return documentNumber;
}
/**
* Copy this node to a given outputter
*
* @param out the Receiver to which the node should be copied
* @param copyOptions a selection of the options defined in {@link net.sf.saxon.om.CopyOptions}
* @param locationId Identifies the location of the instruction
*/
public void copy(Receiver out, int copyOptions, int locationId) throws XPathException {
original.copy(out, copyOptions, locationId);
}
/**
* 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.
*
* For a node other than an element, the method returns null.
*/
public NamespaceBinding[] getDeclaredNamespaces(NamespaceBinding[] buffer) {
return original.getDeclaredNamespaces(buffer);
}
/**
* Set the system identifier for this Source.
*
* The system identifier is optional if the source does not
* get its data from a URL, but it may still be useful to provide one.
* The application can use a system identifier, for example, to resolve
* relative URIs and to include in error messages and warnings.
*
* @param systemId The system identifier as a URL string.
*/
public void setSystemId(String systemId) {
this.systemId = systemId;
}
/**
* Get the typed value.
*
* @return the typed value. If requireSingleton is set to true, the result will always be an
* AtomicValue. In other cases it may be a Value representing a sequence whose items are atomic
* values.
* @since 8.5
*/
public AtomicSequence atomize() throws XPathException {
return original.atomize();
}
/**
* Determine whether this node has the is-id property
*
* @return true if the node is an ID
*/
public boolean isId() {
return original.isId();
}
/**
* Determine whether this node has the is-idref property
*
* @return true if the node is an IDREF or IDREFS element or attribute
*/
public boolean isIdref() {
return original.isIdref();
}
/**
* Determine whether the node has the is-nilled property
*
* @return true if the node has the is-nilled property
*/
public boolean isNilled() {
return original.isNilled();
}
/**
* Return the public identifier for the current document event.
*
* The return value is the public identifier of the document
* entity or of the external parsed entity in which the markup that
* triggered the event appears.
*
* @return A string containing the public identifier, or
* null if none is available.
* @see #getSystemId
*/
/*@Nullable*/
public String getPublicId() {
return (original instanceof SourceLocator ? ((SourceLocator) original).getPublicId() : null);
}
/**
* Create an iterator that makes and returns virtual copies of nodes on the original tree
*
* @param axis the axis to be navigated
* @param newParent the parent of the nodes in the new virtual tree (may be null)
* @param root the root of the virtual tree
* @return the iterator that does the copying
*/
protected VirtualCopier makeCopier(AxisIterator axis, VirtualCopy newParent, NodeInfo root) {
return new VirtualCopier(axis, newParent, root);
}
/**
* VirtualCopier implements the XPath axes as applied to a VirtualCopy node. It works by
* applying the requested axis to the node of which this is a copy. There are two
* complications: firstly, all nodes encountered must themselves be (virtually) copied
* to give them a new identity. Secondly, axes that stray outside the subtree rooted at
* the original copied node must be truncated.
*/
protected class VirtualCopier implements AxisIterator {
protected AxisIterator base;
private VirtualCopy parent;
protected NodeInfo subtreeRoot;
/*@Nullable*/
private NodeInfo current;
public VirtualCopier(AxisIterator base, VirtualCopy parent, NodeInfo subtreeRoot) {
this.base = base;
this.parent = parent;
this.subtreeRoot = subtreeRoot;
}
/**
* Move to the next node, without returning it. Returns true if there is
* a next node, false if the end of the sequence has been reached. After
* calling this method, the current node may be retrieved using the
* current() function.
*/
public boolean moveNext() {
return (next() != null);
}
/**
* Get the next item in the sequence.
*
* @return the next Item. If there are no more nodes, return null.
*/
/*@Nullable*/
public NodeInfo next() {
NodeInfo next = base.next();
if (next != null) {
if (subtreeRoot != null) {
// we're only interested in nodes within the subtree that was copied.
// Assert: once we find a node outside this subtree, all further nodes will also be outside
// the subtree.
if (!isAncestorOrSelf(subtreeRoot, next)) {
return null;
}
}
VirtualCopy vc = createCopy(next, root);
vc.parent = parent;
vc.systemId = systemId;
vc.documentNumber = documentNumber;
next = vc;
}
current = next;
return next;
}
/**
* Get the current item in the sequence.
*
* @return the current item, that is, the item most recently returned by
* next()
*/
/*@Nullable*/
public NodeInfo current() {
return current;
}
/**
* Get the current position
*
* @return the position of the current item (the item most recently
* returned by next()), starting at 1 for the first node
*/
public int position() {
return base.position();
}
public void close() {
base.close();
}
/**
* Return an iterator over an axis, starting at the current node.
*
* @param axis the axis to iterate over, using a constant such as
* {@link net.sf.saxon.om.AxisInfo#CHILD}
* @param test a predicate to apply to the nodes before returning them.
* @throws NullPointerException if there is no current node
*/
public AxisIterator iterateAxis(byte axis, NodeTest test) {
return current.iterateAxis(axis, test);
}
/**
* Return the atomized value of the current node.
*
* @return the atomized value.
* @throws NullPointerException if there is no current node
*/
public Sequence atomize() throws XPathException {
return current.atomize();
}
/**
* Return the string value of the current node.
*
* @return the string value, as an instance of CharSequence.
* @throws NullPointerException if there is no current node
*/
public CharSequence getStringValue() {
return current.getStringValueCS();
}
/**
* Get another iterator over the same sequence of items, positioned at the
* start of the sequence
*
* @return a new iterator over the same sequence
*/
/*@NotNull*/
public AxisIterator getAnother() {
return new VirtualCopier(base.getAnother(), parent, subtreeRoot);
}
/**
* Get properties of this iterator, as a bit-significant integer.
*
* @return the properties of this iterator. This will be some combination of
* properties such as {@link #GROUNDED}, {@link #LAST_POSITION_FINDER},
* and {@link #LOOKAHEAD}. It is always
* acceptable to return the value zero, indicating that there are no known special properties.
* It is acceptable for the properties of the iterator to change depending on its state.
*/
public int getProperties() {
return 0;
}
/**
* Test whether a node is an ancestor-or-self of another
*
* @param a the putative ancestor
* @param d the putative descendant
* @return true if a is an ancestor of d
*/
private boolean isAncestorOrSelf(/*@NotNull*/ NodeInfo a, NodeInfo d) {
while (true) {
if (a.isSameNodeInfo(d)) {
return true;
}
d = d.getParent();
if (d == null) {
return false;
}
}
}
/**
* Method to create the virtual copy of a node encountered when navigating. This method
* is separated out so that it can be overridden in a subclass.
*
* @param node the node to be copied
* @param root the root of the tree
* @return the virtual copy
*/
protected VirtualCopy createCopy(NodeInfo node, NodeInfo root) {
return VirtualCopy.makeVirtualCopy(node, root);
}
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy