net.sf.saxon.functions
Class Evaluate
java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.functions.SystemFunction
net.sf.saxon.functions.Evaluate
- All Implemented Interfaces:
- Serializable, SourceLocator, EvaluableItem, SequenceIterable, InstructionInfoProvider
public class Evaluate
- extends SystemFunction
This class implements the saxon:evaluate(), saxon:expression(), and saxon:eval() extension functions,
which are specially-recognized by the system because they need access to parts of the static context
- See Also:
- Serialized Form
Nested Class Summary |
static class |
Evaluate.PreparedExpression
Inner class PreparedExpression represents a compiled XPath expression together
with the standard variables $p1 .. |
Methods inherited from class net.sf.saxon.functions.SystemFunction |
addContextDocumentArgument, addDocToPathMap, computeCardinality, computeSpecialProperties, copy, getDetails, getErrorCodeForTypeErrors, getItemType, 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, typeCheck |
Methods inherited from class net.sf.saxon.expr.Expression |
addToPathMap, adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, explain, findParentOf, getCardinality, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError |
staticContext
IndependentContext staticContext
details
InstructionDetails details
EVALUATE
public static final int EVALUATE
- See Also:
- Constant Field Values
EXPRESSION
public static final int EXPRESSION
- See Also:
- Constant Field Values
EVAL
public static final int EVAL
- See Also:
- Constant Field Values
EVALUATE_NODE
public static final int EVALUATE_NODE
- See Also:
- Constant Field Values
Evaluate
public Evaluate()
getRequiredType
protected SequenceType getRequiredType(int arg)
- Get the required type of the nth argument
- Overrides:
getRequiredType
in class SystemFunction
- Parameters:
arg
- the number of the argument whose type is requested, zero-based
- Returns:
- the required type of the argument as defined in the function signature
checkArguments
public void checkArguments(ExpressionVisitor visitor)
throws XPathException
- Method supplied by each class of function to check arguments during parsing, when all
the argument expressions have been read
- Overrides:
checkArguments
in class SystemFunction
- Parameters:
visitor
- the expression visitor
- Throws:
XPathException
preEvaluate
public Expression preEvaluate(ExpressionVisitor visitor)
throws XPathException
- preEvaluate: for saxon:expression, if the expression is
known at compile time, then it is compiled at compile time.
In other cases 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
- Throws:
XPathException
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
iterate
public SequenceIterator iterate(XPathContext c)
throws XPathException
- Iterate over the results of the function
- Specified by:
iterate
in interface SequenceIterable
- Overrides:
iterate
in class Expression
- Parameters:
c
- supplies the context for evaluation
- Returns:
- a SequenceIterator that can be used to iterate over the result
of the expression
- 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