com.novell.xml.xpath
Class NodeSet

java.lang.Object
  com.novell.xml.xpath.NodeSet

All Implemented Interfaces:

ContextNodeList, Expression, ExpressionValue

Direct Known Subclasses:

InsertionOrderNodeSet

public class NodeSet

extends Object

implements ExpressionValue, Expression, ContextNodeList

Class to represent a node-set expression value

Nested Class Summary

protected class

NodeSet.Mark

Field Summary

protected static Class	argType
protected static DocumentOrderComparator	nodeComparator
protected Set	set

Fields inherited from interface com.novell.xml.xpath.ExpressionValue

BOOLEAN, EXTENDED, NATIVE, NODE_SET, NUMBER, STRING

Fields inherited from interface com.novell.xml.xpath.ContextNodeList

DOCUMENT_ORDER, REVERSE_DOCUMENT_ORDER, UNKNOWN_ORDER

Constructor Summary

NodeSet()
Construct a new, empty node-set

NodeSet(Collection copy)
Construct a new node-set and initialize it to contain the members in the passed collection

NodeSet(NodeSet copy)
Construct a new node-set with the same content as the passed node-set

Method Summary

void	add(DocumentFragment fragment) Add (the children of) a DocumentFragment to a node-set If any node is a duplicate of a member of the set it will not be added
void	add(Node node) Add an arbitrary node to a node-set.
void	castFrom(Object type) Convert from a different type of expression value to the NodeSet type NOTE: this will ALWAYS throw an exception (unless the "from" type is a node-set), since there is no type type can be converted to a node-set
boolean	contains(Node node) Return true if the passed node is contained in the set
int	count() Return a count of nodes in the context node list.
void	dump(PrintWriter writer) Output a human-readable form for the value
void	dump(PrintWriter writer, int indent) Print the expression in a readable form for debugging.
ExpressionValue	evaluate(Node contextNode, ExpressionContext context) Evaluate the expression with repect to the passed context
Node	first() Return the first node in the context node list.
static Class	getArgType() Return the Class object for objects of this type.
boolean	getBooleanValue() Return boolean value of expression value (will convert to boolean if value is not of type boolean)
ContextListMark	getMark() Return a marker to a position in a ContextNodeList.
Object	getNativeValue() return the underlying native value (java.lang.Boolean, java.lang.Double, etc.)
NodeSet	getNodeSetValue() Return node-set value of this ExpressionValue.
double	getNumberValue() Return numeric value of ExpressionValue.
Class	getResultType() Return the Class object describing the result type of the expression.
String	getStringValue() Return string value of this ExpressionValue.
int	getValueType() Return type of expression value
boolean	isConstant() Return true if the expression is a constant value.
boolean	isEmpty() Return true if this node-set has no members
Node	next() Return a the subsequent node in the context node list after a call to first() or next()
int	order() Return order in which nodes are returned from first()-next()
int	position() Return the position of the last node returned by a call to first() or next()
void	registerForReset(XPathResetRegistrar registrar) Register this expression or any subexpression that implements XPathResetCache with an object that wants to call resetCache()
void	remove(Node node) Remove a member of the node-set.
Node	returnToMark(ContextListMark mark) Go to a position in a ContextNodeList previously marked with getMark()
String	toString() Provide a readable description for debugging.
void	union(NodeSet rhs) Perform a union operation between this node-set and another node-set.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

set

protected Set set

argType

protected static Class argType

nodeComparator

protected static DocumentOrderComparator nodeComparator

Constructor Detail

NodeSet

public NodeSet()

Construct a new, empty node-set

NodeSet

public NodeSet(Collection copy)
        throws Exception

Construct a new node-set and initialize it to contain the members in the passed collection

Parameters:

copy - A collection of Node objects

Throws:

Exception - Error

NodeSet

public NodeSet(NodeSet copy)

Construct a new node-set with the same content as the passed node-set

Parameters:

copy - The node-set to copy

Method Detail

getArgType

public static Class getArgType()

Return the Class object for objects of this type.

This is used for FunctionSignature objects.

Returns:

The Class object corresponding to NodeSet

add

public void add(Node node)

Add an arbitrary node to a node-set. If the node is a duplicate of a member of the set it will not be added

Parameters:

node - node to add

add

public void add(DocumentFragment fragment)

Add (the children of) a DocumentFragment to a node-set If any node is a duplicate of a member of the set it will not be added

Parameters:

fragment - DocumentFragment to add

remove

public void remove(Node node)

Remove a member of the node-set.

Parameters:

node - The node to be removed

contains

public boolean contains(Node node)

Return true if the passed node is contained in the set

Parameters:

node - The node to check

Returns:

True if the passed node is contained in the set

union

public void union(NodeSet rhs)

Perform a union operation between this node-set and another node-set. The resulting union will be in document order.

Parameters:

rhs - The right-hand operand of the union operator

isEmpty

public boolean isEmpty()

Return true if this node-set has no members

Returns:

true is node-set is empty, false otherwise

toString

public String toString()

Provide a readable description for debugging.

Returns:

String representation

evaluate

public ExpressionValue evaluate(Node contextNode,
                                ExpressionContext context)

Evaluate the expression with repect to the passed context

Specified by:

evaluate in interface Expression

Parameters:

contextNode - context node for expression evaluation

context - expression context for expression evaluation

Returns:

result of evaluating expression

isConstant

public boolean isConstant()

Return true if the expression is a constant value.

Specified by:

isConstant in interface Expression

Returns:

True is expression is constant, false otherwise.

getResultType

public Class getResultType()

Return the Class object describing the result type of the expression.

Specified by:

getResultType in interface Expression

Returns:

A Class object.

registerForReset

public void registerForReset(XPathResetRegistrar registrar)

Register this expression or any subexpression that implements XPathResetCache with an object that wants to call resetCache()

Specified by:

registerForReset in interface Expression

dump

public void dump(PrintWriter writer,
                 int indent)

Print the expression in a readable form for debugging.

Specified by:

dump in interface Expression

Parameters:

writer - The output device.

indent - Number of tabs to indent the result.

getValueType

public int getValueType()

Return type of expression value

Specified by:

getValueType in interface ExpressionValue

Returns:

ExpressionValue.BOOLEAN, ExpressionValue.NUMBER, etc.

castFrom

public void castFrom(Object type)
              throws XPathConversionException

Convert from a different type of expression value to the NodeSet type

NOTE: this will ALWAYS throw an exception (unless the "from" type is a node-set), since there is no type type can be converted to a node-set

Specified by:

castFrom in interface ExpressionValue

Parameters:

type - The object to convert from.

Throws:

XPathConversionException

getBooleanValue

public boolean getBooleanValue()
                        throws XPathConversionException

Return boolean value of expression value (will convert to boolean if value is not of type boolean)

Specified by:

getBooleanValue in interface ExpressionValue

Returns:

true or false

Throws:

XPathConversionException

getNumberValue

public double getNumberValue()
                      throws XPathConversionException

Return numeric value of ExpressionValue. Will convert to a number if value is not of NUMBER type

Specified by:

getNumberValue in interface ExpressionValue

Returns:

numeric value

Throws:

XPathConversionException

getStringValue

public String getStringValue()

Return string value of this ExpressionValue. Will convert to a string if underlying type is not string.

Specified by:

getStringValue in interface ExpressionValue

Returns:

String value of ExpressionValue

getNodeSetValue

public NodeSet getNodeSetValue()
                        throws XPathConversionException

Return node-set value of this ExpressionValue. Will NOT convert an underlying type to a node-set.

Specified by:

getNodeSetValue in interface ExpressionValue

Throws:

XPathConversionException

getNativeValue

public Object getNativeValue()

return the underlying native value (java.lang.Boolean, java.lang.Double, etc.)

Specified by:

getNativeValue in interface ExpressionValue

Returns:

The native java class that is the value

dump

public void dump(PrintWriter writer)

Output a human-readable form for the value

Specified by:

dump in interface ExpressionValue

Parameters:

writer - Output device

first

public Node first()

Return the first node in the context node list.

Specified by:

first in interface ContextNodeList

Returns:

First node in list. null is returned if list is empty

next

public Node next()

Return a the subsequent node in the context node list after a call to first() or next()

Specified by:

next in interface ContextNodeList

Returns:

The next node in the context node list. null is returned if there are no more nodes in the node list

count

public int count()

Return a count of nodes in the context node list.

NOTE: this should be implemented with lazy evaluation if possible, since context node lists can be very large, depending on the document.

Specified by:

count in interface ContextNodeList

Returns:

Count of nodes in the context node list.

position

public int position()

Return the position of the last node returned by a call to first() or next()

Specified by:

position in interface ContextNodeList

Returns:

Node position in node list. 0 is returned if no nodes have been returned. Once first() or next() return null (indicating no more nodes in list) the return will be the position of the last node in the list.

order

public int order()

Return order in which nodes are returned from first()-next()

Specified by:

order in interface ContextNodeList

Returns:

DOCUMENT_ORDER or REVERSE_DOCUMENT_ORDER

getMark

public ContextListMark getMark()

Return a marker to a position in a ContextNodeList. This marker can be used later in a call to returnToMark() to return to a particular position in the list.

Specified by:

getMark in interface ContextNodeList

Returns:

an opaque marker

returnToMark

public Node returnToMark(ContextListMark mark)

Go to a position in a ContextNodeList previously marked with getMark()

Specified by:

returnToMark in interface ContextNodeList

Parameters:

mark - mark returned from getMark()

Returns:

The node at the mark