net.sf.saxon.functions
Class Current

java.lang.Object
  extended by net.sf.saxon.expr.Expression
      extended by net.sf.saxon.expr.FunctionCall
          extended by net.sf.saxon.functions.SystemFunction
              extended by net.sf.saxon.functions.Current
All Implemented Interfaces:
Serializable, SourceLocator, EvaluableItem, SequenceIterable, XSLTFunction, InstructionInfoProvider

public class Current
extends SystemFunction
implements XSLTFunction

Implement the XSLT current() function

See Also:
Serialized Form

Field Summary
static StructuredQName FN_CURRENT
          The name of the Current function
 
Fields inherited from class net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
 
Constructor Summary
Current()
           
 
Method Summary
 int computeSpecialProperties()
          Get the static properties of this expression (other than its type).
 Item evaluateItem(XPathContext c)
          Evaluate in a general context
 int getIntrinsicDependencies()
          Determine the dependencies
 Expression preEvaluate(ExpressionVisitor visitor)
          preEvaluate: this method suppresses compile-time evaluation by doing nothing (because the value of the expression depends on the runtime context)
 
Methods inherited from class net.sf.saxon.functions.SystemFunction
addDocToPathMap, checkArguments, computeCardinality, copy, getDetails, getErrorCodeForTypeErrors, getItemType, makeSystemFunction, optimize, setDetails
 
Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionName, simplify, toString, typeCheck
 
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, effectiveBooleanValue, evaluateAsString, explain, findParentOf, getCardinality, getColumnNumber, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterate, iterateEvents, markTailFunctionCalls, process, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation
 
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

FN_CURRENT

public static StructuredQName FN_CURRENT
The name of the Current function

Constructor Detail

Current

public Current()
Method Detail

computeSpecialProperties

public int computeSpecialProperties()
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 property bit is set, it is true, but if it is unset, the value is unknown.

Overrides:
computeSpecialProperties in class SystemFunction
Returns:
the special properties, as a bit-significant integer

preEvaluate

public Expression preEvaluate(ExpressionVisitor visitor)
preEvaluate: this method suppresses compile-time evaluation by doing nothing (because the value of the expression depends on the runtime context)

Overrides:
preEvaluate in class FunctionCall
Parameters:
visitor - an expression visitor
Returns:
the result of the early evaluation, or the original expression, or potentially a simplified expression

evaluateItem

public Item evaluateItem(XPathContext c)
                  throws XPathException
Evaluate in a general context

Specified by:
evaluateItem in interface EvaluableItem
Overrides:
evaluateItem in class Expression
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:
getIntrinsicDependencies in class Expression
Returns:
a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty


Copyright (C) Michael H. Kay. All rights reserved.