net.sf.saxon.functions
Class Available

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.Available
All Implemented Interfaces:
Serializable, SourceLocator, EvaluableItem, SequenceIterable, XSLTFunction, InstructionInfoProvider

public class Available
extends SystemFunction
implements XSLTFunction

This class supports the XSLT element-available and function-available functions.

See Also:
Serialized Form

Field Summary
static int ELEMENT_AVAILABLE
           
static int FUNCTION_AVAILABLE
           
static int TYPE_AVAILABLE
           
 
Fields inherited from class net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
 
Constructor Summary
Available()
           
 
Method Summary
 void checkArguments(ExpressionVisitor visitor)
          Method called during static type checking
 Item evaluateItem(XPathContext context)
          Run-time evaluation.
 Expression preEvaluate(ExpressionVisitor visitor)
          preEvaluate: this method uses the static context to do early evaluation of the function if the argument is known (which is the normal case)
 
Methods inherited from class net.sf.saxon.functions.SystemFunction
addDocToPathMap, computeCardinality, computeSpecialProperties, 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, getIntrinsicDependencies, 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

ELEMENT_AVAILABLE

public static final int ELEMENT_AVAILABLE
See Also:
Constant Field Values

FUNCTION_AVAILABLE

public static final int FUNCTION_AVAILABLE
See Also:
Constant Field Values

TYPE_AVAILABLE

public static final int TYPE_AVAILABLE
See Also:
Constant Field Values
Constructor Detail

Available

public Available()
Method Detail

checkArguments

public void checkArguments(ExpressionVisitor visitor)
                    throws XPathException
Description copied from class: SystemFunction
Method called during static type checking

Overrides:
checkArguments in class SystemFunction
Parameters:
visitor - the expression visitor
Throws:
XPathException

preEvaluate

public Expression preEvaluate(ExpressionVisitor visitor)
                       throws XPathException
preEvaluate: this method uses the static context to do early evaluation of the function if the argument is known (which is the normal case)

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

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException
Run-time evaluation. This is the only thing in the spec that requires information about in-scope functions to be available at run-time. However, we keep it because it's handy for some other things such as saxon:evaluate().

Specified by:
evaluateItem in interface EvaluableItem
Overrides:
evaluateItem in class Expression
Parameters:
context - 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


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