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java.lang.Object net.sf.saxon.expr.Expression net.sf.saxon.expr.SuppliedParameterReference
public class SuppliedParameterReference
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.
Field Summary |
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Fields inherited from class net.sf.saxon.expr.Expression |
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EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD |
Constructor Summary | |
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SuppliedParameterReference(int slot)
Constructor |
Method Summary | |
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int |
computeCardinality()
Get the static cardinality |
Expression |
copy()
Copy an expression. |
Item |
evaluateItem(XPathContext context)
Evaluate an expression as a single item. |
ValueRepresentation |
evaluateVariable(XPathContext c)
Get the value of this expression in a given context. |
void |
explain(ExpressionPresenter destination)
Diagnostic print of expression structure. |
int |
getIntrinsicDependencies()
Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. |
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the expression, if possible. |
int |
getSlotNumber()
Get the slot number |
SequenceIterator |
iterate(XPathContext context)
Get the value of this expression in a given context. |
Expression |
optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions. |
void |
setSuppliedType(SequenceType type)
Set the type of the supplied value if known |
String |
toString()
The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath. |
Expression |
typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Perform type checking of an expression and its subexpressions. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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public SuppliedParameterReference(int slot)
slot
- identifies this parameter. The value -1 indicates that the value is to be obtained
from the dynamic stack held in the context object.Method Detail |
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public int getSlotNumber()
public void setSuppliedType(SequenceType type)
type
- of the supplied valuepublic Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
Expression
This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.
If the implementation returns a value other than "this", then it is required to ensure that the location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.
typeCheck
in class Expression
visitor
- an expression visitorcontextItemType
- the static type of "." at the point where this expression is invoked.
The parameter is set to null if it is known statically that the context item will be undefined.
If the type of the context item is not known statically, the argument is set to
Type.ITEM_TYPE
XPathException
- if an error is discovered during this phase
(typically a type error)public Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
Expression
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.
optimize
in class Expression
visitor
- an expression visitorcontextItemType
- the static type of "." at the point where this expression is invoked.
The parameter is set to null if it is known statically that the context item will be undefined.
If the type of the context item is not known statically, the argument is set to
Type.ITEM_TYPE
XPathException
- if an error is discovered during this phase
(typically a type error)public ItemType getItemType(TypeHierarchy th)
getItemType
in class Expression
th
- the type hierarchy cache
public int getIntrinsicDependencies()
getIntrinsicDependencies
in class Expression
public int computeCardinality()
computeCardinality
in class Expression
public Expression copy()
copy
in class Expression
public ValueRepresentation evaluateVariable(XPathContext c) throws XPathException
c
- the XPathContext which contains the relevant variable bindings
XPathException
- if the variable is undefinedpublic SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in class Expression
context
- the XPathContext which contains the relevant variable bindings
XPathException
- if the variable is undefinedpublic Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in class Expression
context
- The context in which the expression is to be evaluated
XPathException
- if any dynamic error occurs evaluating the
expressionpublic void explain(ExpressionPresenter destination)
explain
in class Expression
destination
- the expression presenter used to display the structurepublic String toString()
toString
in class Expression
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