MXmlEngXPathEvaluationContext Class Reference

#include <xml/dom/xmlengxpathevaluationcontext.h>

class MXmlEngXPathEvaluationContext

Public Member Functions
pure virtual void	AppendToResult(const TXmlEngNode)
pure virtual void	AppendToResult(const TXmlEngNamespace, const TXmlEngElement)
pure virtual void	AppendToResult(const RXmlEngNodeSet)
pure virtual TUint	ArgCount()
pure virtual const RXmlEngXPathResult	Argument(TUint)
pure virtual void *	ExtendedContext()
pure virtual void	InitializeNodeSetResult()
pure virtual const RXmlEngXPathResult	Result()
pure virtual void	SetResult(TReal)
pure virtual void	SetResult(TBool)
pure virtual void	SetResultL(const TDesC8 &)

Detailed Description

Provides the XPath evaluation context interface. An object of this type provides the argument values to an extension function to be evalutated and stores the result of evalutation.

Objects of this type are not registered with the XPath library and must be destroyed by their owner.

Any memory allocated by this object must be freed when the object is destroyed.

Member Function Documentation

AppendToResult ( const TXmlEngNode )

void

AppendToResult

(

const TXmlEngNode

aNode

)

[pure virtual]

Appends a node to the node set result. InitializeNodeSetResult() should be called prior to the first call to an AppendToResult() method.

This method will return and do nothing if a previous OOM condition in the underlying libxml2 library has not been cleared. See libxml2_modules.h.

Pre-condition: OOM_FLAG==0, otherwise method returns and does nothing.

Parameter	Description
aNode	Node to be added

AppendToResult ( const TXmlEngNamespace, const TXmlEngElement )

void	AppendToResult	(	const TXmlEngNamespace	aAppendedNsNode,
			const TXmlEngElement	aNsParentNode
		)	[pure virtual]

Appends a namespace node to the node set result. InitializeNodeSetResult() should be called prior to the first call to an AppendToResult() method.

A namespace node is the representation of an existing namespace declaration within an element node. This function cannot be used to add a new namespace declaration, rather it adds an existing namespace declaration attached to aNsParentNode.

Parameter	Description
aAppendedNsNode	A namspace node to add to the node set result.
aNsParentNode	An element node that holds the namespace declaration represented by aAppendedNsNode.

AppendToResult ( const RXmlEngNodeSet )

void

AppendToResult

(

const RXmlEngNodeSet

aNodeSet

)

[pure virtual]

Appends a node set to the node set result. Nodes are merged into a resulting node set. InitializeNodeSetResult() should be called prior to the first call to an AppendToResult() method.

This method will return and do nothing if a previous OOM condition in the underlying libxml2 library has not been cleared. See libxml2_modules.h.

Pre-condition: OOM_FLAG==0, otherwise method returns and does nothing.

Parameter	Description
aNodeSet	The node set to be appended

ArgCount ( )

TUint

ArgCount

(

)

[pure virtual]

Gets the number of arguments provided.

Returns: The number of arguments provided

Argument ( TUint )

const RXmlEngXPathResult

Argument

(

TUint

aIndex

)

[pure virtual]

Gets an argument by index. Does not transfer ownership. Index starts at 0.

Pre-condition: 0 <= aIndex < ArgCount(). Function panics if precondition not met.

Returns: The n-th argument of the function

ExtendedContext ( )

void *

ExtendedContext

(

)

[pure virtual]

Gets the data specified in RXmlEngXPathExpression::SetExtendedContext() for the expression currently being evaluated.

InitializeNodeSetResult ( )

void

InitializeNodeSetResult

(

)

[pure virtual]

Sets the type of result to node set and initializes a new node set. Any existing result node set is replaced.

Result ( )

const RXmlEngXPathResult

Result

(

)

[pure virtual]

Gets the result written so far. The result is undefined before SetResult(), InitializeNodeSetResult() or AppendToResult() have been called.

Pre-condition: SetResult() or InitializeNodeSetResult() and AppendToResult() have been previously called.

Returns: The result evaluated by the function so far.

SetResult ( TReal )

void

SetResult

(

TReal

aNumber

)

[pure virtual]

Sets the type of result to floating point number and stores the number as the result.

Parameter	Description
aNumber	The number to store as the result

SetResult ( TBool )

void

SetResult

(

TBool

aBoolean

)

[pure virtual]

Sets the type of result to boolean and stores the value as the result.

Parameter	Description
aBoolean	The value to store as the result

SetResultL ( const TDesC8 & )

void

SetResultL

(

const TDesC8 &

aString

)

[pure virtual]

Sets the type of result to string and stores the string as the result.

Parameter	Description
aString	The string to store as the result