net.sf.saxon.tree.wrapper
Class VirtualCopy

java.lang.Object
  extended by net.sf.saxon.tree.wrapper.VirtualCopy
All Implemented Interfaces:
Source, SourceLocator, PullEvent, Item, NodeInfo, ValueRepresentation
Direct Known Subclasses:
VirtualDocumentCopy, VirtualUntypedCopy

public class VirtualCopy
extends Object
implements NodeInfo, 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.


Nested Class Summary
protected  class VirtualCopy.VirtualCopier
          VirtualCopier implements the XPath axes as applied to a VirtualCopy node.
 
Field Summary
protected  long documentNumber
           
protected  NodeInfo original
           
protected  VirtualCopy parent
           
protected  NodeInfo root
           
protected  String systemId
           
 
Fields inherited from interface net.sf.saxon.om.NodeInfo
ALL_NAMESPACES, EMPTY_NAMESPACE_LIST, IS_DTD_TYPE, IS_NILLED, LOCAL_NAMESPACES, NO_NAMESPACES
 
Fields inherited from interface net.sf.saxon.om.ValueRepresentation
EMPTY_VALUE_ARRAY
 
Constructor Summary
protected VirtualCopy(NodeInfo base)
          Protected constructor: create a virtual copy of a node
 
Method Summary
 Value atomize()
          Get the typed value.
 int compareOrder(NodeInfo other)
          Determine the relative position of this node and another node, in document order.
 void copy(Receiver out, int copyOptions, int 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(int fingerprint)
          Get the 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
 int[] getDeclaredNamespaces(int[] buffer)
          Get all namespace undeclarations and undeclarations defined on this element.
 String getDisplayName()
          Get the display name of this node.
 long getDocumentNumber()
          Get the document number of the document containing this node.
 DocumentInfo getDocumentRoot()
          Get the root node, if it is a document node.
 int getFingerprint()
          Get fingerprint.
 int getLineNumber()
          Get line number
 String getLocalPart()
          Get the local part of the name of this node.
 int getNameCode()
          Get name code.
 NamePool getNamePool()
          Get the NamePool that holds the namecode for this node
 int getNodeKind()
          Get the kind of 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
 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.
 int getTypeAnnotation()
          Get the type annotation of this node, if any.
 SequenceIterator getTypedValue()
          Get the typed value of the item
 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()
 boolean isId()
          Determine whether this node has the is-id property
 boolean isIdref()
          Determine whether this node has the is-idref property
 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.
 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, NodeInfo root)
          Create an iterator that makes and returns virtual copies of nodes on the original tree
static VirtualCopy makeVirtualCopy(NodeInfo original, NodeInfo root)
          Public factory method: create a virtual copy of a node
 void setDocumentNumber(long documentNumber)
          Set the unique document number of the virtual document.
 void setSystemId(String systemId)
          Set the system identifier for this Source.
protected  VirtualCopy wrap(NodeInfo node)
          Wrap a node in a VirtualCopy.
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

systemId

protected String systemId

documentNumber

protected long documentNumber

original

protected NodeInfo original

parent

protected VirtualCopy parent

root

protected NodeInfo root
Constructor Detail

VirtualCopy

protected VirtualCopy(NodeInfo base)
Protected constructor: create a virtual copy of a node

Parameters:
base - the node to be copied
Method Detail

makeVirtualCopy

public static VirtualCopy makeVirtualCopy(NodeInfo original,
                                          NodeInfo root)
Public factory method: create a virtual copy of a node

Parameters:
original - the node to be copied
root - the root of the tree containing 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 in a VirtualCopy. This method is designed for subclassing

Parameters:
node - the node to be wrapped

setDocumentNumber

public void setDocumentNumber(long documentNumber)
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

Parameters:
documentNumber - the document number to be allocated. This can be obtained from the DocumentNumberAllocator which is accessible from the Configuration using Configuration.getDocumentNumberAllocator()

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

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())

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
Specified by:
getStringValue in interface ValueRepresentation
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
Specified by:
getStringValueCS in interface ValueRepresentation
Returns:
the string value of the item
See Also:
Item.getStringValue()

getNameCode

public int getNameCode()
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.

Specified by:
getNameCode in interface NodeInfo
Returns:
an integer name code, which may be used to obtain the actual node name from the name pool
See Also:
allocate, getFingerprint

getFingerprint

public int getFingerprint()
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.

Specified by:
getFingerprint in interface NodeInfo
Returns:
an integer fingerprint; two nodes with the same fingerprint have the same expanded QName

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

getNamePool

public NamePool getNamePool()
Get the NamePool that holds the namecode for this node

Specified by:
getNamePool in interface NodeInfo
Returns:
the namepool

getTypeAnnotation

public int getTypeAnnotation()
Get the type annotation of this node, if any.

Specified by:
getTypeAnnotation in interface NodeInfo
Returns:
the type annotation of the node.
See Also:
Type

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:
Axis

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:
Axis

getAttributeValue

public String getAttributeValue(int fingerprint)
Get the value of a given attribute of this node

Specified by:
getAttributeValue in interface NodeInfo
Parameters:
fingerprint - The fingerprint of the attribute name
Returns:
the attribute value if it exists or null if not

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

getDocumentRoot

public DocumentInfo getDocumentRoot()
Get the root node, if it is a document node.

Specified by:
getDocumentRoot in interface NodeInfo
Returns:
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.

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.

getDocumentNumber

public long getDocumentNumber()
Get the document number of the document containing this node. For a free-standing orphan node, just return the hashcode.

Specified by:
getDocumentNumber in interface NodeInfo
Returns:
the document number of the document containing this node

copy

public void copy(Receiver out,
                 int copyOptions,
                 int 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

getDeclaredNamespaces

public int[] getDeclaredNamespaces(int[] 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 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.


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.

getTypedValue

public SequenceIterator getTypedValue()
                               throws XPathException
Get the typed value of the item

Specified by:
getTypedValue in interface Item
Returns:
the typed value of the item. In general this will be a sequence
Throws:
XPathException - where no typed value is available, e.g. for an element with complex content

atomize

public Value atomize()
              throws XPathException
Get the typed value. The result of this method will always be consistent with the method Item.getTypedValue(). However, this method is often more convenient and may be more efficient, especially in the common case where the value is expected to be a singleton.

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
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
Returns:
A string containing the public identifier, or null if none is available.
See Also:
getSystemId()

makeCopier

protected VirtualCopy.VirtualCopier makeCopier(AxisIterator axis,
                                               VirtualCopy newParent,
                                               NodeInfo root)
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)
root - the root of the virtual tree
Returns:
the iterator that does the copying


Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.