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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.om;
import net.sf.saxon.Configuration;
import net.sf.saxon.event.Receiver;
import net.sf.saxon.event.ReceiverOption;
import net.sf.saxon.event.Sender;
import net.sf.saxon.expr.parser.Loc;
import net.sf.saxon.lib.ActiveSource;
import net.sf.saxon.lib.ParseOptions;
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.Err;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.tree.iter.AxisIterator;
import net.sf.saxon.tree.util.Navigator;
import net.sf.saxon.type.*;
import org.xml.sax.Locator;
import javax.xml.transform.SourceLocator;
/**
* The NodeInfo interface represents a node in Saxon's implementation of the XPath 2.0 data model.
* Note that several NodeInfo objects may represent the same node. To test node identity, the
* method {@link #equals(Object)} should be used. An exception to this rule applies for
* document nodes, where the correspondence between document nodes and DocumentInfo objects is one to
* one. NodeInfo objects are never reused: a given NodeInfo object represents the same node for its entire
* lifetime.
* This is the primary interface for accessing trees in Saxon, and it forms part of the public
* Saxon API. Methods that form part of the public API are (since Saxon 8.4)
* labelled with a JavaDoc "since" tag: classes and methods that have no such label should not be
* regarded as stable interfaces.
* The interface represented by this class is at a slightly higher level than the abstraction described
* in the W3C data model specification, in that it includes support for the XPath axes, rather than exposing
* the lower-level properties (such as "parent" and "children") directly. All navigation within trees,
* except for a few convenience methods, is done by following the axes using the {@link #iterateAxis} method.
* This allows different implementations of the XPath tree model to implement axis navigation in different ways.
* Some implementations may choose to use the helper methods provided in class {@link net.sf.saxon.tree.util.Navigator}.
* Note that the stability of this interface applies to classes that use the interface,
* not to classes that implement it. The interface may be extended in future to add new methods.
* New implementations of NodeInfo are advised also to implement the methods in interface
* ExtendedNodeInfo, which will be moved into this interface at some time in the future.
*
* @since 8.4. Extended with three extra methods, previously in ExtendedNodeInfo, in 9.1.
* In 9.7, DocumentInfo is no longer defined as a sub-interface; it is replaced with TreeInfo,
* which contains information about any XML node tree, whether or not it is rooted at a document node.
* In 9.8, default implementations are provided for some of the methods, making it easier to create
* a new implementation of this interface.
*/
public interface NodeInfo extends Item, Location
// On Saxon-CS, NodeInfo doesn't implement Source because of multiple-inheritance problems
// Instead, use the asActiveSource() method to get a Source (this also works on Java)
, ActiveSource
{
/**
* Get information about the tree to which this NodeInfo belongs
* @return the TreeInfo
* @since 9.7
*/
TreeInfo getTreeInfo();
/**
* Convenience method to get the Configuration. Always returns the same result as {@code getTreeInfo().getConfiguration()}
* @return the Configuration to which the tree belongs. The default implementation invokes
* {@code getTreeInfo().getConfiguration()}.
* @since 8.4
*/
default Configuration getConfiguration() {
return getTreeInfo().getConfiguration();
}
/**
* Get the kind of node. This will be a value such as {@link net.sf.saxon.type.Type#ELEMENT}
* or {@link net.sf.saxon.type.Type#ATTRIBUTE}. There are seven kinds of node: documents, elements, attributes,
* text, comments, processing-instructions, and namespaces.
*
* @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
* @since 8.4
*/
int getNodeKind();
/**
* Determine whether this is the same node as another node.
* Note that two different NodeInfo instances can represent the same conceptual node.
* Therefore the "==" operator should not be used to test node identity. The equals()
* method should give the same result as isSameNodeInfo(), but since this rule was introduced
* late it might not apply to all implementations.
* 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.
* From Saxon 9.9 this method has a default implementation that invokes {@code equals()},
* and all Saxon implementations of {@code NodeInfo} rely on this default implementation.
* The method is retained for backwards compatibility, but applications are advised to
* use the {@code equals()} method in preference, and user-defined implementations of
* {@code NodeInfo} are advised to rely on the default implementation. In particular,
* implementations of {@code equals()} should not invoke {@code 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. The default implementation returns
* {@code equals(other)}
*/
default boolean isSameNodeInfo(NodeInfo other) {
return equals(other);
}
/**
* 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.
*/
boolean equals(Object 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.
*/
int hashCode();
/**
* Get the System ID for the node. Note this is not the
* same as the base URI: the base URI can be modified by xml:base, but
* the system ID cannot. The base URI is used primarily for resolving
* relative URIs within the content of the document. The system ID is
* used primarily in conjunction with a line number, for identifying the
* location of elements within the source XML, in particular when errors
* are found. For a document node, the System ID represents the value of
* the document-uri property as defined in the XDM data model.
*
* @return the System Identifier of the entity in the source document
* containing the node, or null if not known or not applicable.
* @since 8.4
*/
/*@Nullable*/
@Override
String getSystemId();
/**
* Get the Public ID of the entity containing the node. This method
* is provided largely so that NodeInfo can act as a {@link Locator}
* or {@link SourceLocator}, and many implementations return null.
* @return the Public Identifier of the entity in the source document
* containing the node, or null if not known or not applicable.
* The default implementation returns null.
* @since 9.7
*/
@Override
default String getPublicId() {
return null;
}
/**
* 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. Where the
* node does not have a base URI of its own, the base URI of its parent node is returned.
*
* @return the base URI of the node. This may be null if the base URI is unknown, including the case
* where the node has no parent.
* @since 8.4
*/
String getBaseURI();
/**
* Get line number. Line numbers are not maintained by default, except for
* stylesheets and schema documents. Line numbering can be requested using the
* -l option on the command line, or by setting options on the TransformerFactory
* or the Configuration before the source document is built.
* The granularity of line numbering is normally the element level: for other nodes
* such as text nodes and attributes, the line number of the parent element will normally be returned.
* In the case of a tree constructed by taking input from a SAX parser, the line number will reflect the
* SAX rules: that is, the line number of an element is the line number where the start tag ends. This
* may be a little confusing where elements have many attributes spread over multiple lines, or where
* single attributes (as can easily happen with XSLT 2.0 stylesheets) occupy several lines.
* In the case of a tree constructed by a stylesheet or query, the line number may reflect the line in
* the stylesheet or query that caused the node to be constructed.
* The line number can be read from within an XPath expression using the Saxon extension function
* saxon:line-number()
*
* @return the line number of the node in its original source document; or
* -1 if not available. The default implementation returns -1.
* @since 8.4
*/
@Override
default int getLineNumber() {
return -1;
}
/**
* Get column number. Column numbers are not maintained by default. Column numbering
* can be requested in the same way as line numbering; but a tree implementation can ignore
* the request.
* The granularity of column numbering is normally the element level: for other nodes
* such as text nodes and attributes, the line number of the parent element will normally be returned.
* In the case of a tree constructed by taking input from a SAX parser, the column number will reflect the
* SAX rules: that is, the column number of an element is the column number where the start tag ends. This
* may be a little confusing where elements have many attributes spread over multiple lines, or where
* single attributes (as can easily happen with XSLT 2.0 stylesheets) occupy several lines.
* In the case of a tree constructed by a stylesheet or query, the column number may reflect the line in
* the stylesheet or query that caused the node to be constructed.
* The column number can be read from within an XPath expression using the Saxon extension function
* saxon:column-number()
*
* @return the column number of the node in its original source document; or
* -1 if not available. The default implementation returns -1.
* @since 9.1
*/
@Override
default int getColumnNumber() {
return -1;
}
/**
* Determine the relative position of this node and another node, in document order.
* 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. To obtain a global ordering
* of nodes, the application should first compare the result of getDocumentNumber(),
* and only if the document number is the same should compareOrder() be called.
*
* @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())
* @since 8.4
*/
int compareOrder(NodeInfo other);
/**
* Ask whether this NodeInfo implementation holds a fingerprint identifying the name of the
* node in the NamePool. If the answer is true, then the {@link #getFingerprint} method must
* return the fingerprint of the node. If the answer is false, then the {@link #getFingerprint}
* method should throw an {@code UnsupportedOperationException}. In the case of unnamed nodes
* such as text nodes, the result can be either true (in which case getFingerprint() should
* return -1) or false (in which case getFingerprint may throw an exception).
* @return true if the implementation of this node provides fingerprints.
* @since 9.8; previously Saxon relied on using FingerprintedNode as a marker interface.
*/
boolean hasFingerprint();
/**
* 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.
* The fingerprint contains no information about the namespace prefix. For a name
* in the null namespace, the fingerprint is the same as the name code.
*
* @return an integer fingerprint; two nodes with the same fingerprint have
* the same expanded QName. For unnamed nodes (text nodes, comments, document nodes,
* and namespace nodes for the default namespace), returns -1.
* @throws UnsupportedOperationException if this kind of node does not hold
* namepool fingerprints (specifically, if {@link #hasFingerprint()} returns false).
* @since 8.4 (moved into FingerprintedNode at 9.7; then back into NodeInfo at 9.8).
*/
int 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.
* @since 8.4
*/
String 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 an element or attribute that is not in a namespace, or for a processing
* instruction, returns an empty string.
* @since 8.4
*/
String getURI();
/**
* Get the display name of this node, in the form of a lexical QName.
* 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, returns
* an empty string.
* @since 8.4
*/
String getDisplayName();
/**
* 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, returns a zero-length string.
*
* @return The prefix of the name of the node.
* @since 8.4
*/
String getPrefix();
/**
* 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.
* The default implementation returns {@link BuiltInAtomicType#UNTYPED_ATOMIC} for attribute
* nodes, {@link Untyped#getInstance} for element and document nodes, and null otherwise
* @since 9.4
*/
default SchemaType getSchemaType() {
switch (getNodeKind()) {
case Type.ATTRIBUTE:
return BuiltInAtomicType.UNTYPED_ATOMIC;
case Type.DOCUMENT:
case Type.ELEMENT:
return Untyped.getInstance();
default:
return null;
}
}
/**
* Get the typed value. This will either be a single AtomicValue or a value whose items are
* atomic values.
* @return the typed value of the node
* @throws XPathException if the node has no typed value, for example if
* it is an element node with element-only content
* @since 8.5. Changed in 9.5 to return the new type AtomicSequence.
*/
@Override
AtomicSequence atomize() throws XPathException;
/**
* Get the NodeInfo object representing the parent of this node
*
* @return the parent of this node; null if this node has no parent
* @since 8.4
*/
/*@Nullable*/
NodeInfo getParent();
/**
* 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 {@link AxisInfo}
* @return an AxisIterator that delivers the nodes reached by the axis in
* turn. The nodes are returned in axis order (document order for a forwards
* axis, reverse document order for a reverse axis). The default implementation
* returns {@code iterateAxis(axisNumber, AnyNodeTest.getInstance()}.
* @throws UnsupportedOperationException if the namespace axis is
* requested and this axis is not supported for this implementation.
* @see AxisInfo
* @since 8.4
*/
default AxisIterator iterateAxis(int 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 {@link AxisInfo}
* @param predicate A condition to be satisfied by the returned nodes; nodes
* that do not satisfy this condition are not included in the result
* @return an AxisIterator that delivers the nodes reached by the axis in
* turn. The nodes are returned in axis order (document order for a forwards
* axis, reverse document order for a reverse axis).
* @throws UnsupportedOperationException if the namespace axis is
* requested and this axis is not supported for this implementation.
* @see AxisInfo
* @since 8.4. Changed in 10.0 to accept any {@code Predicate} as the second argument. It is still
* possible to supply a {@link NodeTest}, because {@code NodeTest} implements {@code Predicate}.
*/
AxisIterator iterateAxis(int axisNumber, NodePredicate predicate);
/**
* 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
*/
/*@Nullable*/
String getAttributeValue(/*@NotNull*/ String uri, /*@NotNull*/ String 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. If this node has no parent,
* then the method returns this node.
* @since 8.4
*/
NodeInfo getRoot();
/**
* Determine whether the node has any children.
* Note: the result is equivalent to
* iterateAxis(Axis.CHILD).next() != null
*
* @return True if the node has one or more children
* @since 8.4
*/
boolean hasChildNodes();
/**
* Return the sequence of children of this node, as an {@code Iterable}. This
* method is designed to allow iteration over the children in a Java "for each" loop,
* in the form for (NodeInfo child : children()) {...}
* @return the children of the node, as an {@code Iterable}.
*/
default Iterable children() {
return new Navigator.ChildrenAsIterable(this);
}
default Iterable children(NodePredicate filter) {
return new Navigator.ChildrenAsIterable(this, filter);
}
default AttributeMap attributes() {
AttributeMap atts = EmptyAttributeMap.getInstance();
if (getNodeKind() == Type.ELEMENT) {
AxisIterator iter = iterateAxis(AxisInfo.ATTRIBUTE);
NodeInfo attr;
while ((attr = iter.next()) != null) {
atts = atts.put(new AttributeInfo(NameOfNode.makeName(attr), (SimpleType) attr.getSchemaType(),
attr.getStringValue(),
Loc.NONE,
ReceiverOption.NONE));
}
}
return atts;
}
/**
* Construct a character string that uniquely identifies this node.
* Note: a.isSameNode(b) if and only if generateId(a)==generateId(b)
*
* @param buffer a buffer which will be updated to hold a string
* that uniquely identifies this node, across all documents.
* @since 8.7
* Changed in Saxon 8.7 to generate the ID value in a client-supplied buffer
*/
void generateId(StringBuilder buffer);
/**
* Copy this node to a given Receiver.
* This method is primarily for internal use. It should not be considered a stable
* part of the Saxon API.
* The default implementation invokes {@code Navigator.copy(this, out, copyOptions, locationId);} which
* is always adequate.
*
* @param out the Receiver to which the node should be copied. It is the caller's
* responsibility to ensure that this Receiver is open before the method is called
* (or that it is self-opening), and that it is closed after use.
* @param copyOptions a selection of the options defined in {@link CopyOptions}
* @param locationId If non-null, identifies the location of the instruction
* that requested this copy. If null, indicates that the location information
* is not available
* @throws XPathException if any downstream error occurs
* @throws IllegalArgumentException if the node is an attribute or namespace node
*/
default void copy(Receiver out, int copyOptions, Location locationId) throws XPathException {
Navigator.copy(this, out, copyOptions, locationId);
}
/**
* Implement the {@link ActiveSource} interface by delivering the document to a
* {@link Receiver}
*
* @throws XPathException if the receiver reports a failure, for example a validation failure
*/
@Override
default void deliver(Receiver receiver, ParseOptions options) throws XPathException {
Sender.sendDocumentInfo(this, receiver, new Loc(getSystemId(), -1, -1));
}
/**
* Obtain an {@link ActiveSource} object that allows the node to be used as input
* to any method that expects a {@code Source}
* @return an {@code ActiveSource} object representing this node
*/
default ActiveSource asActiveSource() {
return new NodeSource(this);
}
void setSystemId(String systemId);
/**
* 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.)
*
* In many cases (and in particular with Saxon's TinyTree and LinkedTree implementations),
* from 10.0 onwards it is more efficient to call {@link #getAllNamespaces()} to get all the in-scope
* namespaces at once, rather than building up the list be calling {@code getDeclaredNamespaces} on
* each ancestor node.
*
* @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.
*/
NamespaceBinding[] getDeclaredNamespaces(/*@Nullable*/ NamespaceBinding[] buffer);
/**
* 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 ""). The map does NOT include
* the implicit binding of the XML namespace. 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.
*/
NamespaceMap getAllNamespaces();
/**
* Ask whether this node has the is-id property
*
* @return true if the node is an ID. The default
* implementation returns false.
*/
default boolean isId() {
return false;
}
/**
* Ask whether this node has the is-idref property
*
* @return true if the node is an IDREF or IDREFS element or attribute. The default
* implementation returns false.
*/
default boolean isIdref() {
return false;
}
/**
* Ask whether the node has the is-nilled property
*
* @return true if the node has the is-nilled property. The default
* implementation returns false.
*/
default boolean isNilled() {
return false;
}
/**
* Ask whether this is a node in a streamed document
* @return true if the node is in a document being processed using streaming.
* The default implementation returns false.
*/
@Override
default boolean isStreamed() {
return false;
}
/**
* Provide a short string showing the contents of the item, suitable
* for use in error messages
*
* @return a depiction of the item suitable for use in error messages.
* The default implementation returns:
*
* document-node() for a document node<p:local/> for an element node@p:local for an attribute nodetext("In a hole...") for a text node<--You are old, ...--> for a comment node<?pi?> for a processing instruction nodexmlns:p=uri for a namespace node
*/
@Override
default String toShortString() {
switch (getNodeKind()) {
case Type.DOCUMENT:
return "document-node()";
case Type.ELEMENT:
return "<" + getDisplayName() + "/>";
case Type.ATTRIBUTE:
return "@" + getDisplayName();
case Type.TEXT:
return "text(\"" + Err.truncate30(getUnicodeStringValue()) + "\")";
case Type.COMMENT:
return "";
case Type.PROCESSING_INSTRUCTION:
return "";
case Type.NAMESPACE:
String prefix = getLocalPart();
return "xmlns" + (prefix.equals("") ? "" : ":" + prefix) + "=\"" + getUnicodeStringValue() + '"';
default:
return "";
}
}
/**
* Get the genre of this item
*
* @return the genre: specifically, {@link Genre#NODE}. The default implementation (which should not
* be overridden) returns {@link Genre#NODE}.
*/
@Override
default Genre getGenre() {
return Genre.NODE;
}
}