Package net.sf.saxon.functions

Class KeyFn

java.lang.Object

net.sf.saxon.functions.AbstractFunction

net.sf.saxon.functions.SystemFunction

net.sf.saxon.functions.KeyFn

All Implemented Interfaces:

Callable, StatefulSystemFunction, FunctionItem, GroundedValue, Item, Sequence

public class KeyFn
extends SystemFunction
implements StatefulSystemFunction

Constructor Summary

Constructors

Constructor	Description
KeyFn()

Method Summary

Modifier and Type	Method	Description
PathMap.PathMapNodeSet	addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)	Add a representation of this expression to a PathMap.
Sequence	call(XPathContext context, Sequence[] arguments)	Evaluate the expression
SystemFunction	copy()	Make a copy of this SystemFunction.
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

dependsOnContextItem, dynamicCall, equals, export, exportAdditionalArguments, exportAttributes, getArity, getCardinality, getContextNode, getDescription, getDetails, getElaborator, getErrorCodeForTypeErrors, getFunctionItemType, getFunctionName, getIntegerBounds, getNetCost, getOperandRoles, getRequiredType, getResultItemType, getResultItemType, getRetainedStaticContext, getStaticBaseUriString, getStreamerName, getUniStringArg, hashCode, importAttributes, isSequenceVariadic, isTrustedResultType, makeCall, makeFunction, makeFunction40, makeFunctionCall, makeOptimizedFunctionCall, resultIfEmpty, setArity, setDetails, setRetainedStaticContext, supplyTypeInformation, toShortString, toString, typeCheckCaller

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

atomize, deepEqual40, deepEquals, effectiveBooleanValue, getAnnotations, getUnicodeStringValue, isArray, isMap, makeNewContext, simplify, typeCheck

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

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

getGenre

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

asIterable, concatenate, containsNode, materialize

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

getLength, getStringValue, head, isStreamed, itemAt, iterate, reduce, subsequence

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

makeRepeatable

Constructor Details

KeyFn

public KeyFn()

Method Details

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 - expressions supplied as arguments in the function call

Returns:

the properties

copy

public SystemFunction copy()

Description copied from interface: StatefulSystemFunction

Make a copy of this SystemFunction. This is required only for system functions such as regex functions that maintain state on behalf of a particular caller.

Specified by:

copy in interface StatefulSystemFunction

Returns:

a copy of the system function able to contain its own copy of the state on behalf of the caller.

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

addToPathMap

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

Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.

The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.

Parameters:

pathMap - the PathMap to which the expression should be added

pathMapNodeSet - the PathMapNodeSet to which the paths embodied in this expression should be added

Returns:

the pathMapNodeSet representing the points in the source document that are both reachable by this expression, and that represent possible results of this expression. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.

call

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

Evaluate the expression

Specified by:

call in interface Callable

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