net.sf.saxon.tree.wrapper

Class VirtualCopy

java.lang.Object

net.sf.saxon.tree.wrapper.VirtualCopy

All Implemented Interfaces:

Source, SourceLocator, PullEvent, Location, Item, NodeInfo, Sequence, Locator

Direct Known Subclasses:

SnapshotNode, VirtualUntypedCopy

public class VirtualCopy
extends Object
implements NodeInfo

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.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	VirtualCopy.VirtualCopier VirtualCopier implements the XPath axes as applied to a VirtualCopy node.

Field Summary

Fields

Modifier and Type	Field and Description
protected NodeInfo	original
protected VirtualCopy	parent
protected NodeInfo	root
protected String	systemId
protected VirtualTreeInfo	tree

Fields inherited from interface net.sf.saxon.om.NodeInfo

ALL_NAMESPACES, IS_DTD_TYPE, IS_NILLED, LOCAL_NAMESPACES, NO_NAMESPACES

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	VirtualCopy(NodeInfo base, NodeInfo root) Protected constructor: create a virtual copy of a node

Method Summary

Methods

Modifier and Type	Method and Description
AtomicSequence	atomize() Get the typed value.
int	compareOrder(NodeInfo other) Determine the relative position of this node and another node, in document order.
int	comparePosition(NodeInfo other) 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.
void	copy(Receiver out, int copyOptions, Location locationId) Copy this node to a given outputter
boolean	equals(Object other) The equals() method compares nodes for identity.
void	generateId(FastStringBuffer buffer) Get a character string that uniquely identifies this node.
String	getAttributeValue(String uri, String local) Get the string value of a given attribute of this node
String	getBaseURI() Get the Base URI for the node, that is, the URI used for resolving a relative URI contained in the node.
int	getColumnNumber() Get column number
Configuration	getConfiguration() Get the configuration
NamespaceBinding[]	getDeclaredNamespaces(NamespaceBinding[] buffer) Get all namespace undeclarations and undeclarations defined on this element.
String	getDisplayName() Get the display name of this node.
int	getLineNumber() Get line number
String	getLocalPart() Get the local part of the name of this node.
int	getNodeKind() Get the kind of node.
NodeInfo	getOriginalNode() Get the original (wrapped) node
NodeInfo	getParent() Get the NodeInfo object representing the parent of this node
String	getPrefix() Get the prefix of the name of the node.
String	getPublicId() Return the public identifier for the current document event.
NodeInfo	getRoot() Get the root node of the tree containing this node
SchemaType	getSchemaType() Get the type annotation of this node, if any.
String	getStringValue() Return the string value of the node.
CharSequence	getStringValueCS() Get the value of the item as a CharSequence.
String	getSystemId() Get the System ID for the node.
VirtualTreeInfo	getTreeInfo() Get information about the tree to which this NodeInfo belongs
String	getURI() Get the URI part of the name of this node.
boolean	hasChildNodes() Determine whether the node has any children.
int	hashCode() 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()
NodeInfo	head() To implement Sequence, this method returns the item itself
boolean	isId() Determine whether this node has the is-id property
boolean	isIdref() Determine whether this node has the is-idref property
protected boolean	isIncludedInCopy(NodeInfo sourceNode) Ask whether a node in the source tree is within the scope of this virtual copy
boolean	isNilled() Determine whether the node has the is-nilled property
boolean	isSameNodeInfo(NodeInfo other) Determine whether this is the same node as another node.
SequenceIterator	iterate() To implement Sequence, this method returns a singleton iterator that delivers this item in the form of a sequence
AxisIterator	iterateAxis(byte axisNumber) Return an iteration over all the nodes reached by the given axis from this node
AxisIterator	iterateAxis(byte axisNumber, NodeTest nodeTest) Return an iteration over all the nodes reached by the given axis from this node that match a given NodeTest
protected VirtualCopy.VirtualCopier	makeCopier(AxisIterator axis, VirtualCopy newParent, boolean testInclusion) Create an iterator that makes and returns virtual copies of nodes on the original tree
static VirtualCopy	makeVirtualCopy(NodeInfo original) Public factory method: create a virtual tree as a copy of an existing node
Location	saveLocation() Get an immutable copy of this Location object.
void	setSystemId(String systemId) Set the system identifier for this Source.
protected VirtualCopy	wrap(NodeInfo node) Wrap a node within an existing VirtualCopy.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Field Detail

systemId

protected String systemId

original

protected NodeInfo original

parent

protected VirtualCopy parent

root

protected NodeInfo root

tree

protected VirtualTreeInfo tree

Constructor Detail

VirtualCopy

protected VirtualCopy(NodeInfo base,
           NodeInfo root)

Protected constructor: create a virtual copy of a node

Parameters:

base - the node to be copied

root - the node in the source tree corresponding to the root of the virtual tree. This must be an ancestor of the base node

Method Detail

makeVirtualCopy

public static VirtualCopy makeVirtualCopy(NodeInfo original)

Public factory method: create a virtual tree as a copy of an existing node

Parameters:

original - the node to be copied

Returns:

the virtual copy. If the original was already a virtual copy, this will be a virtual copy of the real underlying node.

wrap

protected VirtualCopy wrap(NodeInfo node)

Wrap a node within an existing VirtualCopy.

Parameters:

node - the node to be wrapped

Returns:

a virtual copy of the node

getOriginalNode

public NodeInfo getOriginalNode()

Get the original (wrapped) node

Returns:

the node of which this one is a virtual copy

getTreeInfo

public VirtualTreeInfo getTreeInfo()

Get information about the tree to which this NodeInfo belongs

Specified by:

getTreeInfo in interface NodeInfo

Returns:

the TreeInfo

Since:

9.7

head

public NodeInfo head()

To implement Sequence, this method returns the item itself

Specified by:

head in interface Item

Specified by:

head in interface Sequence

Returns:

this item

iterate

public SequenceIterator iterate()

To implement Sequence, this method returns a singleton iterator that delivers this item in the form of a sequence

Specified by:

iterate in interface Sequence

Returns:

a singleton iterator that returns this item

getNodeKind

public int getNodeKind()

Get the kind of node. This will be a value such as Type.ELEMENT or Type.ATTRIBUTE

Specified by:

getNodeKind in interface NodeInfo

Returns:

an integer identifying the kind of node. These integer values are the same as those used in the DOM

See Also:

Type

isSameNodeInfo

public boolean isSameNodeInfo(NodeInfo other)

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.

Specified by:

isSameNodeInfo in interface NodeInfo

Parameters:

other - the node to be compared with this node

Returns:

true if this NodeInfo object and the supplied NodeInfo object represent the same node in the tree.

equals

public boolean equals(Object other)

The equals() method compares nodes for identity. It is defined to give the same result as isSameNodeInfo().

Specified by:

equals in interface NodeInfo

Overrides:

equals in class Object

Parameters:

other - the node to be compared with this node

Returns:

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.

hashCode

public int hashCode()

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()

Specified by:

hashCode in interface NodeInfo

Overrides:

hashCode in class Object

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.

getSystemId

public String getSystemId()

Get the System ID for the node.

Specified by:

getSystemId in interface Source

Specified by:

getSystemId in interface SourceLocator

Specified by:

getSystemId in interface Location

Specified by:

getSystemId in interface NodeInfo

Specified by:

getSystemId in interface Locator

Returns:

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.

getBaseURI

public String getBaseURI()

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.

Specified by:

getBaseURI in interface NodeInfo

Returns:

the base URI of the node

getLineNumber

public int getLineNumber()

Get line number

Specified by:

getLineNumber in interface SourceLocator

Specified by:

getLineNumber in interface Location

Specified by:

getLineNumber in interface NodeInfo

Specified by:

getLineNumber in interface Locator

Returns:

the line number of the node in its original source document; or -1 if not available

getColumnNumber

public int getColumnNumber()

Get column number

Specified by:

getColumnNumber in interface SourceLocator

Specified by:

getColumnNumber in interface Location

Specified by:

getColumnNumber in interface NodeInfo

Specified by:

getColumnNumber in interface Locator

Returns:

the column number of the node in its original source document; or -1 if not available

saveLocation

public Location saveLocation()

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.

Specified by:

saveLocation in interface Location

compareOrder

public int compareOrder(NodeInfo other)

Determine the relative position of this node and another node, in document order. The other node will always be in the same document.

Specified by:

compareOrder in interface NodeInfo

Parameters:

other - The other node, whose position is to be compared with this node

Returns:

-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())

comparePosition

public int comparePosition(NodeInfo other)

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.

Specified by:

comparePosition in interface NodeInfo

Parameters:

other - The other node, whose position is to be compared with this node

Returns:

AxisInfo.PRECEDING if this node is on the preceding axis of the other node; AxisInfo.FOLLOWING if it is on the following axis; AxisInfo.ANCESTOR if the first node is an ancestor of the second; AxisInfo.DESCENDANT if the first is a descendant of the second; AxisInfo.SELF if they are the same node.

Throws:

UnsupportedOperationException - if either node is an attribute or namespace

Since:

9.5

getStringValue

public String getStringValue()

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.

Specified by:

getStringValue in interface Item

Specified by:

getStringValue in interface NodeInfo

Returns:

the string value of the node

See Also:

Item.getStringValueCS()

getStringValueCS

public CharSequence getStringValueCS()

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.

Specified by:

getStringValueCS in interface Item

Returns:

the string value of the item

See Also:

Item.getStringValue()

getLocalPart

public String getLocalPart()

Get the local part of the name of this node. This is the name after the ":" if any.

Specified by:

getLocalPart in interface NodeInfo

Returns:

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.

getURI

public String getURI()

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.

Specified by:

getURI in interface NodeInfo

Returns:

The URI of the namespace of this node. For an unnamed node, or for a node with an empty prefix, return an empty string.

getPrefix

public String getPrefix()

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.

Specified by:

getPrefix in interface NodeInfo

Returns:

The prefix of the name of the node.

getDisplayName

public String getDisplayName()

Get the display name of this node. For elements and attributes this is [prefix:]localname. For unnamed nodes, it is an empty string.

Specified by:

getDisplayName in interface NodeInfo

Returns:

The display name of this node. For a node with no name, return an empty string.

getConfiguration

public Configuration getConfiguration()

Get the configuration

Specified by:

getConfiguration in interface NodeInfo

Returns:

the Configuration to which the tree belongs

getSchemaType

public SchemaType getSchemaType()

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.

Specified by:

getSchemaType in interface NodeInfo

Returns:

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

getParent

public NodeInfo getParent()

Get the NodeInfo object representing the parent of this node

Specified by:

getParent in interface NodeInfo

Returns:

the parent of this node; null if this node has no parent

iterateAxis

public AxisIterator iterateAxis(byte axisNumber)

Return an iteration over all the nodes reached by the given axis from this node

Specified by:

iterateAxis in interface NodeInfo

Parameters:

axisNumber - an integer identifying the axis; one of the constants defined in class net.sf.saxon.om.Axis

Returns:

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 Also:

AxisInfo

iterateAxis

public AxisIterator iterateAxis(byte axisNumber,
                       NodeTest nodeTest)

Return an iteration over all the nodes reached by the given axis from this node that match a given NodeTest

Specified by:

iterateAxis in interface NodeInfo

Parameters:

axisNumber - an integer identifying the axis; one of the constants defined in class net.sf.saxon.om.Axis

nodeTest - A pattern to be matched by the returned nodes; nodes that do not match this pattern are not included in the result

Returns:

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 Also:

AxisInfo

getAttributeValue

public String getAttributeValue(String uri,
                       String local)

Get the string value of a given attribute of this node

Specified by:

getAttributeValue in interface NodeInfo

Parameters:

uri - the namespace URI of the attribute name. Supply the empty string for an attribute that is in no namespace

local - the local part of the attribute name.

Returns:

the attribute value if it exists, or null if it does not exist. Always returns null if this node is not an element.

getRoot

public NodeInfo getRoot()

Get the root node of the tree containing this node

Specified by:

getRoot in interface NodeInfo

Returns:

the NodeInfo representing the top-level ancestor of this node. This will not necessarily be a document node

hasChildNodes

public boolean hasChildNodes()

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

Specified by:

hasChildNodes in interface NodeInfo

Returns:

True if the node has one or more children

generateId

public void generateId(FastStringBuffer buffer)

Get a character string that uniquely identifies this node. Note: a.isSameNode(b) if and only if generateId(a)==generateId(b)

Specified by:

generateId in interface NodeInfo

Parameters:

buffer - a buffer, to which will be appended a string that uniquely identifies this node, across all documents.

copy

public void copy(Receiver out,
        int copyOptions,
        Location locationId)
          throws XPathException

Copy this node to a given outputter

Specified by:

copy in interface NodeInfo

Parameters:

out - the Receiver to which the node should be copied

copyOptions - a selection of the options defined in CopyOptions

locationId - Identifies the location of the instruction

Throws:

XPathException - if any downstream error occurs

getDeclaredNamespaces

public NamespaceBinding[] getDeclaredNamespaces(NamespaceBinding[] buffer)

Get all namespace undeclarations and undeclarations defined on this element.

Specified by:

getDeclaredNamespaces in interface NodeInfo

Parameters:

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.

Returns:

An array 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 NamespaceBinding objects. 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 VirtualCopy, the method needs to return all namespaces that are in scope for this element, because the virtual copy is assumed to contain copies of all the in-scope namespaces of the original.

setSystemId

public void setSystemId(String systemId)

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.

Specified by:

setSystemId in interface Source

Parameters:

systemId - The system identifier as a URL string.

atomize

public AtomicSequence atomize()
                       throws XPathException

Get the typed value.

Specified by:

atomize in interface Item

Specified by:

atomize in interface NodeInfo

Returns:

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.

Throws:

XPathException - if the node has no typed value, for example if it is an element node with element-only content

Since:

8.5

isId

public boolean isId()

Determine whether this node has the is-id property

Specified by:

isId in interface NodeInfo

Returns:

true if the node is an ID

isIdref

public boolean isIdref()

Determine whether this node has the is-idref property

Specified by:

isIdref in interface NodeInfo

Returns:

true if the node is an IDREF or IDREFS element or attribute

isNilled

public boolean isNilled()

Determine whether the node has the is-nilled property

Specified by:

isNilled in interface NodeInfo

Returns:

true if the node has the is-nilled property

getPublicId

public String getPublicId()

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.

Specified by:

getPublicId in interface SourceLocator

Specified by:

getPublicId in interface Location

Specified by:

getPublicId in interface NodeInfo

Specified by:

getPublicId in interface Locator

Returns:

A string containing the public identifier, or null if none is available.

See Also:

getSystemId()

isIncludedInCopy

protected boolean isIncludedInCopy(NodeInfo sourceNode)

Ask whether a node in the source tree is within the scope of this virtual copy

Parameters:

sourceNode - the node being tested

Returns:

true if the node is within the scope of the subtree

makeCopier

protected VirtualCopy.VirtualCopier makeCopier(AxisIterator axis,
                                   VirtualCopy newParent,
                                   boolean testInclusion)

Create an iterator that makes and returns virtual copies of nodes on the original tree

Parameters:

axis - the axis to be navigated

newParent - the parent of the nodes in the new virtual tree (may be null)

testInclusion - if true, it is necessary to test whether nodes found in the source tree are included in the copy. If false, this test is unnecessary.

Returns:

the iterator that does the copying