Class KeyFn

public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap,
                                           PathMap.PathMapNodeSet pathMapNodeSet)

Add a representation of a doc() call or similar function to a PathMap. This is a convenience method called by the addToPathMap() methods for doc(), document(), collection() and similar functions. These all create a new root expression in the path map.

Overrides:

addToPathMap in interface Expression

Parameters:

pathMap - the PathMap to which the expression should be added

pathMapNodeSet -

Returns:

the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression

public void checkArguments(ExpressionVisitor visitor)
            throws XPathException

Method called during static type checking

Overrides:

checkArguments in interface SystemFunction

public int computeSpecialProperties()

Get the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if a property bit is set, it is true, but if it is unset, the value is unknown.

Overrides:

computeSpecialProperties in interface SystemFunction

public Expression copy()

Copy an expression. This makes a deep copy.

Overrides:

copy in interface SystemFunction

Returns:

the copy of the original expression

public StructuredQName getStaticKeyName()

Get the key name, if known statically. If not known statically, return null.

Returns:

the key name if known, otherwise null

public static KeyFn internalKeyCall(KeyDefinitionSet keySet,
                                    String name,
                                    Expression value,
                                    Expression doc)

Non-standard constructor to create an internal call on key() with a known key definition

Parameters:

keySet - the set of KeyDefinitions (always a single KeyDefinition)

name - the name allocated to the key (first argument of the function)

value - the value being searched for (second argument of the function)

doc - the document being searched (third argument)

Returns:

a call on the key() function

public SequenceIterator iterate(XPathContext context)
            throws XPathException

Enumerate the results of the expression

Specified by:

iterate in interface SequenceIterable

Overrides:

iterate in interface Expression

public Expression preEvaluate(ExpressionVisitor visitor)

preEvaluate: this method suppresses compile-time evaluation by doing nothing

Overrides:

preEvaluate in interface FunctionCall

Parameters:

visitor - the expression visitor

public Expression simplify(ExpressionVisitor visitor)
            throws XPathException

Simplify: add a third implicit argument, the context document

Overrides:

simplify in interface FunctionCall

Parameters:

visitor - the expression visitor

public Expression typeCheck(ExpressionVisitor visitor,
                            ItemType contextItemType)
            throws XPathException

Type-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.

Overrides:

typeCheck in interface FunctionCall