net.sf.saxon.functions

Class String_1

java.lang.Object

net.sf.saxon.om.AbstractItem

net.sf.saxon.functions.AbstractFunction

net.sf.saxon.functions.SystemFunction

net.sf.saxon.functions.ScalarSystemFunction

net.sf.saxon.functions.String_1

All Implemented Interfaces:

PullEvent, Callable, Function, GroundedValue, Item, Sequence

public class String_1
extends ScalarSystemFunction

Implement XPath function string() with a single argument

Field Summary

Fields inherited from class net.sf.saxon.functions.ScalarSystemFunction

ZERO_LENGTH_STRING

Constructor Summary

Constructors

Constructor and Description
String_1()

Method Summary

Methods

Modifier and Type	Method and Description
AtomicValue	evaluate(Item arg, XPathContext context) Abstract method that must be supplied in subclasses to perform the evaluation
ExpressionCompiler	getExpressionCompiler() Return the compiler of the StringFn expression
StringFnAdjunct	getStreamingAdjunct() Get a class that supports streamed evaluation of this expression
Expression	makeOptimizedFunctionCall(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo, Expression... arguments) Allow the function to create an optimized call based on the values of the actual arguments
ZeroOrOne<? extends AtomicValue>	resultWhenEmpty() Method that may be supplied in subclasses, to indicate the result that is returned when an empty sequence is supplied as the argument value.

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

call, makeFunctionCall

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

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

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

atomize, deepEquals, effectiveBooleanValue, getStringValue, getStringValueCS, isArray, isMap, optimize, 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

String_1

public String_1()

Method Detail

evaluate

public AtomicValue evaluate(Item arg,
                   XPathContext context)
                     throws XPathException

Description copied from class: ScalarSystemFunction

Abstract method that must be supplied in subclasses to perform the evaluation

Specified by:

evaluate in class ScalarSystemFunction

Parameters:

arg - the supplied argument

context - the dynamic context

Returns:

the result of the evaluation

Throws:

XPathException - if a dynamic error occurs

resultWhenEmpty

public ZeroOrOne<? extends AtomicValue> resultWhenEmpty()

Description copied from class: ScalarSystemFunction

Method that may be supplied in subclasses, to indicate the result that is returned when an empty sequence is supplied as the argument value. The default is to return the empty sequence

Overrides:

resultWhenEmpty in class ScalarSystemFunction

Returns:

the result of evaluation when the supplied argument is an empty sequence

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

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

getExpressionCompiler

public ExpressionCompiler getExpressionCompiler()

Return the compiler of the StringFn expression

Overrides:

getExpressionCompiler in class SystemFunction

Returns:

the relevant ExpressionCompiler

getStreamingAdjunct

public StringFnAdjunct getStreamingAdjunct()

Get a class that supports streamed evaluation of this expression

Overrides:

getStreamingAdjunct in class SystemFunction

Returns:

the relevant StreamingAdjunct, or null if none is available