net.sf.saxon.functions

Class KeyFn

java.lang.Object

net.sf.saxon.om.AbstractItem

net.sf.saxon.functions.AbstractFunction

net.sf.saxon.functions.SystemFunction

net.sf.saxon.functions.KeyFn

All Implemented Interfaces:

PullEvent, Callable, Function, GroundedValue, Item, Sequence

public class KeyFn
extends SystemFunction

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	KeyFn.SubtreeFilter Mapping class to filter nodes that have the origin node as an ancestor-or-self

Constructor Summary

Constructors

Constructor and Description
KeyFn()

Method Summary

Modifier and Type	Method and Description
Sequence	call(XPathContext context, Sequence[] arguments) Evaluate the expression
Expression	fixArguments(Expression... arguments) Allow the function to create an optimized call based on the values of the actual arguments.
KeyManager	getKeyManager()
NamespaceResolver	getNamespaceResolver()
int	getSpecialProperties(Expression[] arguments) Get the static properties of this expression (other than its type).
static Expression	internalKeyCall(KeyManager keyManager, KeyDefinitionSet keySet, String name, Expression value, Expression doc, RetainedStaticContext rsc) Factory method to create an internal call on key() with a known key definition
protected static Sequence	search(KeyManager keyManager, XPathContext context, Sequence sought, NodeInfo origin, KeyDefinitionSet selectedKeySet)

Methods inherited from class net.sf.saxon.functions.SystemFunction

equals, export, exportAttributes, getArity, getCardinality, getContextNode, getDescription, getDetails, getErrorCodeForTypeErrors, getExpressionCompiler, getFunctionItemType, getFunctionName, getIntegerBounds, getOperandRoles, getRequiredType, getResultItemType, getResultItemType, getRetainedStaticContext, getStaticBaseUriString, getStreamingAdjunct, importAttributes, isTrustedResultType, makeCall, makeFunction, makeFunctionCall, makeOptimizedFunctionCall, resultIfEmpty, setArity, setDetails, setRetainedStaticContext, supplyTypeInformation, typeCheckCaller

Methods inherited from class net.sf.saxon.functions.AbstractFunction

atomize, deepEquals, effectiveBooleanValue, getStringValue, getStringValueCS, isArray, isMap, simplify, typeCheck

Methods inherited from class net.sf.saxon.om.AbstractItem

getLength, head, itemAt, iterate, reduce, subsequence

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.om.Function

iterate

Methods inherited from interface net.sf.saxon.om.Item

head

Methods inherited from interface net.sf.saxon.om.GroundedValue

getLength, head, itemAt, reduce, subsequence

Constructor Detail

KeyFn

public KeyFn()

Method Detail

getKeyManager

public KeyManager getKeyManager()

getNamespaceResolver

public NamespaceResolver getNamespaceResolver()

internalKeyCall

public static Expression internalKeyCall(KeyManager keyManager,
                                         KeyDefinitionSet keySet,
                                         String name,
                                         Expression value,
                                         Expression doc,
                                         RetainedStaticContext rsc)

Factory method 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

getSpecialProperties

public int getSpecialProperties(Expression[] arguments)

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:

getSpecialProperties in class SystemFunction

Parameters:

arguments -

fixArguments

public Expression fixArguments(Expression... arguments)
                        throws XPathException

Allow the function to create an optimized call based on the values of the actual arguments. This binds the key definition in the common case where the key name is defined statically

Overrides:

fixArguments in class SystemFunction

Parameters:

arguments - the supplied arguments to the function call. Note: modifying the contents of this array should not be attempted, it is likely to have no effect.

Returns:

either a function call on this function, or an expression that delivers the same result, or null indicating that no optimization has taken place

Throws:

XPathException - if an error is detected

call

public Sequence call(XPathContext context,
                     Sequence[] arguments)
              throws XPathException

Evaluate the expression

Parameters:

context - the dynamic evaluation context

arguments - the values of the arguments, supplied as Sequences

Returns:

the result of the evaluation, in the form of a Sequence

Throws:

XPathException - if a dynamic error occurs during the evaluation of the expression

search

protected static Sequence search(KeyManager keyManager,
                                 XPathContext context,
                                 Sequence sought,
                                 NodeInfo origin,
                                 KeyDefinitionSet selectedKeySet)
                          throws XPathException

Throws:

XPathException