net.sf.saxon.expr.flwor

Class LocalVariableBinding

java.lang.Object

net.sf.saxon.expr.flwor.LocalVariableBinding

All Implemented Interfaces:

Binding, LocalBinding

public class LocalVariableBinding
extends java.lang.Object
implements LocalBinding

Represents the defining occurrence of a variable declared within a FLWOR expression, for example the $p in "for $x at $p in ...". Also used for the variables bound to the context item in a pattern that uses current()

Constructor Summary

Constructors

Constructor and Description
LocalVariableBinding(StructuredQName name, SequenceType type) Create a LocalVariableBinding

Method Summary

Modifier and Type	Method and Description
void	addReference(VariableReference ref, boolean isLoopingReference) Register a variable reference that refers to the variable bound in this expression
LocalVariableBinding	copy() Make a copy of this LocalVariableBinding (except for the slot number)
Sequence	evaluateVariable(XPathContext context) Get the value of the range variable
IntegerValue[]	getIntegerBoundsForVariable() If the variable is bound to an integer, get the minimum and maximum possible values.
int	getLocalSlotNumber() If this is a local variable held on the local stack frame, return the corresponding slot number.
int	getNominalReferenceCount() Get the (nominal) count of the number of references to this variable
SequenceType	getRequiredType() Get the required type (declared type) of the variable
StructuredQName	getVariableQName() Get the name of the variable
boolean	isAssignable() Test whether it is permitted to assign to the variable using the saxon:assign extension element.
boolean	isGlobal() Indicate whether the binding is local or global.
boolean	isIndexedVariable() Ask whether the binding is to be indexed
void	setIndexedVariable() Indicate that the variable bound by this let expression should be indexable (because it is used in an appropriate filter expression)
void	setRequiredType(SequenceType type) Set the required or inferred type of the variable
void	setSlotNumber(int nr) Set the slot number for the range variable
void	setVariableQName(StructuredQName variableName) Set the name of the variable

Methods inherited from class java.lang.Object

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

Constructor Detail

LocalVariableBinding

public LocalVariableBinding(StructuredQName name,
                            SequenceType type)

Create a LocalVariableBinding

Parameters:

name - the name of the variable

type - the static type of the variable

Method Detail

copy

public LocalVariableBinding copy()

Make a copy of this LocalVariableBinding (except for the slot number)

Returns:

a copy of the binding

getVariableQName

public StructuredQName getVariableQName()

Get the name of the variable

Specified by:

getVariableQName in interface Binding

Returns:

the name of the variable

setRequiredType

public void setRequiredType(SequenceType type)

Set the required or inferred type of the variable

Parameters:

type - the required or inferred type

getRequiredType

public SequenceType getRequiredType()

Get the required type (declared type) of the variable

Specified by:

getRequiredType in interface Binding

Returns:

the required type

getIntegerBoundsForVariable

public IntegerValue[] getIntegerBoundsForVariable()

If the variable is bound to an integer, get the minimum and maximum possible values. Return null if unknown or not applicable

Specified by:

getIntegerBoundsForVariable in interface Binding

Returns:

a pair of integers containing the minimum and maximum values for the integer value; or null if the value is not an integer or the range is unknown

getNominalReferenceCount

public int getNominalReferenceCount()

Get the (nominal) count of the number of references to this variable

Returns:

zero if there are no references, one if there is a single reference that is not in a loop, some higher number if there are multiple references (or a single reference in a loop), or the special value @link RangeVariable#FILTERED} if there are any references in filter expressions that require searching.

addReference

public void addReference(VariableReference ref,
                         boolean isLoopingReference)

Register a variable reference that refers to the variable bound in this expression

Specified by:

addReference in interface Binding

Parameters:

ref -

isLoopingReference - - true if the reference occurs within a loop, such as the predicate of a filter expression

setIndexedVariable

public void setIndexedVariable()

Indicate that the variable bound by this let expression should be indexable (because it is used in an appropriate filter expression)

Specified by:

setIndexedVariable in interface LocalBinding

isIndexedVariable

public boolean isIndexedVariable()

Description copied from interface: LocalBinding

Ask whether the binding is to be indexed

Specified by:

isIndexedVariable in interface LocalBinding

Returns:

true if the variable value can be indexed

setVariableQName

public void setVariableQName(StructuredQName variableName)

Set the name of the variable

Parameters:

variableName - the name of the variable

setSlotNumber

public void setSlotNumber(int nr)

Set the slot number for the range variable

Parameters:

nr - the slot number to be used

getLocalSlotNumber

public int getLocalSlotNumber()

If this is a local variable held on the local stack frame, return the corresponding slot number. In other cases, return -1.

Specified by:

getLocalSlotNumber in interface LocalBinding

Returns:

the slot number on the local stack frame

evaluateVariable

public Sequence evaluateVariable(XPathContext context)
                          throws XPathException

Get the value of the range variable

Specified by:

evaluateVariable in interface Binding

Parameters:

context - the XPath dynamic evaluation context

Returns:

the result of evaluating the variable

Throws:

XPathException - if an error occurs while evaluating the variable

isAssignable

public boolean isAssignable()

Test whether it is permitted to assign to the variable using the saxon:assign extension element. This will only be for an XSLT global variable where the extra attribute saxon:assignable="yes" is present.

Specified by:

isAssignable in interface Binding

Returns:

true if the binding is assignable

isGlobal

public boolean isGlobal()

Indicate whether the binding is local or global. A global binding is one that has a fixed value for the life of a query or transformation; any other binding is local.

Specified by:

isGlobal in interface Binding

Returns:

true if the binding is global