net.sf.saxon.ma.map

Class MapFunctionSet.MapGet

java.lang.Object

net.sf.saxon.functions.AbstractFunction

net.sf.saxon.functions.SystemFunction

net.sf.saxon.ma.map.MapFunctionSet.MapGet

All Implemented Interfaces:

Callable, Function, GroundedValue, Item, Sequence

Enclosing class:

MapFunctionSet

public static class MapFunctionSet.MapGet
extends SystemFunction

Implementation of the XPath 3.1 function map:get(Map, key) => value

Constructor Summary

Constructors

Constructor and Description
MapGet()

Method Summary

Modifier and Type	Method and Description
Sequence	call(XPathContext context, Sequence[] arguments) Call the Callable.
int	getCardinality(Expression[] args) Get the cardinality, given knowledge of the actual arguments
ItemType	getResultItemType(Expression[] args) Get the return type, given knowledge of the actual arguments
Expression	makeOptimizedFunctionCall(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo, Expression... arguments) Allow the function to create an optimized call based on the values of the actual arguments
void	supplyTypeInformation(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType, Expression[] arguments) Method called during static type checking.

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

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

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

atomize, 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.Function

getGenre

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.GroundedValue

asIterable, concatenate, containsNode, materialize

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

makeRepeatable

Constructor Detail

MapGet

public MapGet()

Method Detail

supplyTypeInformation

public void supplyTypeInformation(ExpressionVisitor visitor,
                                  ContextItemStaticInfo contextItemType,
                                  Expression[] arguments)
                           throws XPathException

Method called during static type checking. This method may be implemented in subclasses so that functions can take advantage of knowledge of the types of the arguments that will be supplied.

Overrides:

supplyTypeInformation in class SystemFunction

Parameters:

visitor - an expression visitor, providing access to the static context and configuration

contextItemType - information about whether the context item is set, and what its type is

arguments - the expressions appearing as arguments in the function call

Throws:

XPathException - if an error is detected

getResultItemType

public ItemType getResultItemType(Expression[] args)

Get the return type, given knowledge of the actual arguments

Overrides:

getResultItemType in class SystemFunction

Parameters:

args - the actual arguments supplied

Returns:

the best available item type that the function will return

getCardinality

public int getCardinality(Expression[] args)

Get the cardinality, given knowledge of the actual arguments

Overrides:

getCardinality in class SystemFunction

Parameters:

args - the actual arguments supplied

Returns:

the most precise available cardinality that the function will return

makeOptimizedFunctionCall

public Expression makeOptimizedFunctionCall(ExpressionVisitor visitor,
                                            ContextItemStaticInfo contextInfo,
                                            Expression... arguments)
                                     throws XPathException

Allow the function to create an optimized call based on the values of the actual arguments

Overrides:

makeOptimizedFunctionCall in class SystemFunction

Parameters:

visitor - the expression visitor

contextInfo - information about the context item

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

Description copied from interface: Callable

Call the Callable.

Parameters:

context - the dynamic evaluation context

arguments - the values of the arguments, supplied as Sequences.

Generally it is advisable, if calling iterate() to process a supplied sequence, to call it only once; if the value is required more than once, it should first be converted to a GroundedValue by calling the utility method SequenceTool.toGroundedValue().

If the expected value is a single item, the item should be obtained by calling Sequence.head(): it cannot be assumed that the item will be passed as an instance of Item or AtomicValue.

It is the caller's responsibility to perform any type conversions required to convert arguments to the type expected by the callee. An exception is where this Callable is explicitly an argument-converting wrapper around the original Callable.

Returns:

the result of the evaluation, in the form of a Sequence. It is the responsibility of the callee to ensure that the type of result conforms to the expected result type.

Throws:

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