Package net.sf.saxon.functions

Class StartsWith

java.lang.Object

net.sf.saxon.functions.AbstractFunction

net.sf.saxon.functions.SystemFunction

net.sf.saxon.functions.CollatingFunctionFixed

net.sf.saxon.functions.StartsWith

All Implemented Interfaces:

Callable, StatefulSystemFunction, FunctionItem, GroundedValue, Item, Sequence

public class StartsWith
extends CollatingFunctionFixed

Implements the fn:starts-with() function, with the collation already known

Constructor Summary

Constructors

Constructor	Description
StartsWith()

Method Summary

Modifier and Type	Method	Description
BooleanValue	call(XPathContext context, Sequence[] arguments)	Evaluate the function
boolean	isSubstringMatchingFunction()	Ask whether this function needs a collation that can handle substring matching
Expression	makeOptimizedFunctionCall(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo, Expression... arguments)	Allow the function to create an optimized call based on the values of the actual arguments
static boolean	startsWith(UnicodeString arg0, UnicodeString arg1, SubstringMatcher collator)

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

copy, exportAttributes, getAtomicComparer, getPreAllocatedAtomicComparer, getStringCollator, importAttributes, preAllocateComparer, setCollationName, setRetainedStaticContext

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

dependsOnContextItem, dynamicCall, equals, export, exportAdditionalArguments, fixArguments, getArity, getCardinality, getContextNode, getDescription, getDetails, getElaborator, getErrorCodeForTypeErrors, getFunctionItemType, getFunctionName, getIntegerBounds, getNetCost, getOperandRoles, getRequiredType, getResultItemType, getResultItemType, getRetainedStaticContext, getSpecialProperties, getStaticBaseUriString, getStreamerName, getUniStringArg, hashCode, isSequenceVariadic, isTrustedResultType, makeCall, makeFunction, makeFunction40, makeFunctionCall, resultIfEmpty, setArity, setDetails, 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

StartsWith

public StartsWith()

Method Details

isSubstringMatchingFunction

public boolean isSubstringMatchingFunction()

Description copied from class: CollatingFunctionFixed

Ask whether this function needs a collation that can handle substring matching

Overrides:

isSubstringMatchingFunction in class CollatingFunctionFixed

Returns:

true in the case of functions such as contains() and starts-with() where substring matching is required. Returns false by default;

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

startsWith

public static boolean startsWith(UnicodeString arg0,
 UnicodeString arg1,
 SubstringMatcher collator)

call

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

Evaluate the function

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