net.sf.saxon.sxpath
Class XPathVariable
java.lang.Object
net.sf.saxon.sxpath.XPathVariable
- Binding, Serializable, VariableDeclaration
public final class XPathVariable
extends java.lang.Object
An object representing an XPath variable for use in the standalone XPath API. The object
can only be created by calling the declareVariable method of class
IndependentContext
.
Note that once declared, this object is thread-safe: it does not hold the actual variable
value, which means it can be used with any number of evaluations of a given XPath expression,
in series or in parallel.
A variable can be given a value by calling
XPathDynamicContext.setVariable(XPathVariable,ValueRepresentation)
.
Note that the value of the variable is not held in the XPathVariable object, but in the
XPathDynamicContext, which means that the XPathVariable itself can be used in multiple threads.
evaluateVariable
public ValueRepresentation evaluateVariable(XPathContext context)
Get the value of the variable. This method is used by the XPath execution engine
to retrieve the value. Note that the value is not held within the variable itself,
but within the dunamic context.
- evaluateVariable in interface Binding
context
- The dynamic evaluation context
- The value of the variable
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.
- getLocalSlotNumber in interface Binding
getRequiredType
public SequenceType getRequiredType()
Get the required type of this variable. If no required type has been specified,
the type item()*
is returned.
- getRequiredType in interface Binding
- the required type of the variable
isAssignable
public final 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.
- isAssignable in interface Binding
isGlobal
public boolean isGlobal()
Ask 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. An XPath
variable is treated as a local variable (largely because it is held on the stack frame)
- isGlobal in interface Binding
make
protected static XPathVariable make(StructuredQName name)
Factory method, for use by the declareVariable method of class IndependentContext
name
- the name of the variable to create
- the constructed XPathVariable
registerReference
public void registerReference(BindingReference ref)
Method called by the XPath expression parser to register a reference to this variable.
This method should not be called by users of the API.
- registerReference in interface VariableDeclaration
setRequiredType
public void setRequiredType(SequenceType requiredType)
Set the required type of this variable. If no required type is specified,
the type item()*
is assumed.
requiredType
- the required type
setSlotNumber
public void setSlotNumber(int slotNumber)
Set the slot number allocated to this variable. This method is for internal use.
slotNumber
- the slot number to be allocated