net.sf.saxon.expr
Class SuppliedParameterReference

java.lang.Object
  |
  +--net.sf.saxon.expr.ComputedExpression
        |
        +--net.sf.saxon.expr.SuppliedParameterReference

All Implemented Interfaces:

Expression, java.io.Serializable

public class SuppliedParameterReference

extends ComputedExpression

Supplied parameter reference: this is an internal expression used to refer to the value of the n'th parameter supplied on a template call (apply-templates). It is used within a type-checking expression designed to check the consistency of the supplied value with the required type. This type checking is all done at run-time, because the binding of apply-templates to actual template rules is entirely dynamic.

See Also:

Serialized Form

Field Summary

 

Fields inherited from class net.sf.saxon.expr.ComputedExpression

lineNumber, NO_ARGUMENTS, staticProperties

 

Constructor Summary

SuppliedParameterReference(int slot)           Constructor

 

Method Summary
Expression	analyze(StaticContext env)           Type-check the expression.
int	computeCardinality()           Get the static cardinality
void	display(int level, NamePool pool)           Diagnostic print of expression structure
boolean	equals(java.lang.Object other)           Test if this expression is the same as another expression.
Item	evaluateItem(XPathContext c)           Evaluate an expression as a single item.
int	getIntrinsicDependencies()           Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.
ItemType	getItemType()           Determine the data type of the expression, if possible.
SequenceIterator	iterate(XPathContext c)           Get the value of this variable in a given context.
Expression	simplify()           Simplify the expression.

 

Methods inherited from class net.sf.saxon.expr.ComputedExpression

computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getDependencies, getLineNumber, getSourceLocator, getSpecialProperties, getSubExpressions, markTailFunctionCalls, promote, setLineNumber, typeError

 

Methods inherited from class java.lang.Object

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

 

Constructor Detail

SuppliedParameterReference

public SuppliedParameterReference(int slot)

Constructor

Parameters:

slot - identifies this parameter

simplify

public Expression simplify()

Simplify the expression. Does nothing.

Specified by:

simplify in interface Expression

Overrides:

simplify in class ComputedExpression

Returns:

the simplified expression

analyze

public Expression analyze(StaticContext env)
                   throws XPathException

Type-check the expression. Not applicable.

Parameters:

env - the static context of the expression

Returns:

the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

XPathException

getItemType

public ItemType getItemType()

Determine the data type of the expression, if possible.

Returns:

Type.ITEM, because we don't know the type of the supplied value in advance.

computeCardinality

public int computeCardinality()

Get the static cardinality

Specified by:

computeCardinality in class ComputedExpression

Returns:

ZERO_OR_MORE, because we don't know the type of the supplied value in advance.

equals

public boolean equals(java.lang.Object other)

Test if this expression is the same as another expression. (Note, we only compare expressions that have the same static and dynamic context).

Overrides:

equals in class java.lang.Object

getIntrinsicDependencies

public int getIntrinsicDependencies()

Description copied from class: ComputedExpression

Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".

Overrides:

getIntrinsicDependencies in class ComputedExpression

Returns:

a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

iterate

public SequenceIterator iterate(XPathContext c)
                         throws XPathException

Get the value of this variable in a given context.

Specified by:

iterate in interface Expression

Overrides:

iterate in class ComputedExpression

Parameters:

c - the XPathContext which contains the relevant variable bindings

Returns:

the value of the variable, if it is defined

Throws:

XPathException - if the variable is undefined

evaluateItem

public Item evaluateItem(XPathContext c)
                  throws XPathException

Description copied from class: ComputedExpression

Evaluate an expression as a single item. This always returns either a single Item or null (denoting the empty sequence). No conversion is done. This method should not be used unless the static type of the expression is a subtype of "item" or "item?": that is, it should not be called if the expression may return a sequence. There is no guarantee that this condition will be detected.

Specified by:

evaluateItem in interface Expression

Overrides:

evaluateItem in class ComputedExpression

Parameters:

c - The context in which the expression is to be evaluated

Returns:

the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence

Throws:

XPathException - if any dynamic error occurs evaluating the expression

display

public void display(int level,
                    NamePool pool)

Diagnostic print of expression structure

Parameters:

level - indentation level for this expression