Package net.sf.saxon.functions
Class Lang
- java.lang.Object
-
- net.sf.saxon.expr.Expression
-
- net.sf.saxon.expr.FunctionCall
-
- net.sf.saxon.functions.SystemFunction
-
- net.sf.saxon.functions.Lang
-
- All Implemented Interfaces:
java.io.Serializable,javax.xml.transform.SourceLocator,LocationProvider,SaxonLocator,EvaluableItem,SequenceIterable,InstructionInfo,org.xml.sax.Locator
public class Lang extends SystemFunction
- See Also:
- Serialized Form
-
-
Field Summary
-
Fields inherited from class net.sf.saxon.functions.SystemFunction
operation
-
Fields inherited from class net.sf.saxon.expr.FunctionCall
argument
-
Fields inherited from class net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
-
-
Constructor Summary
Constructors Constructor Description Lang()
-
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description ItemevaluateItem(XPathContext c)Evaluate in a general contextintgetIntrinsicDependencies()Determine the dependenciesstatic booleanisLang(java.lang.String arglang, NodeInfo target)Test whether the context node has the given language attributeExpressionpreEvaluate(ExpressionVisitor visitor)preEvaluate: this method suppresses compile-time evaluation by doing nothingExpressiontypeCheck(ExpressionVisitor visitor, ItemType contextItemType)Type-check the expression.-
Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, addDocToPathMap, checkArguments, computeCardinality, computeSpecialProperties, copy, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault
-
Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, checkArgumentCount, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString
-
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterate, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
-
-
-
-
Method Detail
-
preEvaluate
public Expression preEvaluate(ExpressionVisitor visitor)
preEvaluate: this method suppresses compile-time evaluation by doing nothing- Overrides:
preEvaluatein classFunctionCall- Parameters:
visitor- an expression visitor- Returns:
- the result of the early evaluation, or the original expression, or potentially a simplified expression
-
typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
Description copied from class:FunctionCallType-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.- Overrides:
typeCheckin classFunctionCall- Parameters:
visitor- an expression visitorcontextItemType- the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set toType.ITEM_TYPE- Returns:
- the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
- Throws:
XPathException- if an error is discovered during this phase (typically a type error)
-
evaluateItem
public Item evaluateItem(XPathContext c) throws XPathException
Evaluate in a general context- Specified by:
evaluateItemin interfaceEvaluableItem- Overrides:
evaluateItemin classExpression- Parameters:
c- The context in which the expression is to be evaluated- Returns:
- the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
- Throws:
XPathException- if any dynamic error occurs evaluating the expression
-
getIntrinsicDependencies
public int getIntrinsicDependencies()
Determine the dependencies- Overrides:
getIntrinsicDependenciesin classExpression- Returns:
- a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
-
isLang
public static boolean isLang(java.lang.String arglang, NodeInfo target)Test whether the context node has the given language attribute- Parameters:
arglang- the language being testedtarget- the target node
-
-