Package net.sf.saxon.functions
Class BooleanFn
java.lang.Object
net.sf.saxon.functions.AbstractFunction
net.sf.saxon.functions.SystemFunction
net.sf.saxon.functions.BooleanFn
- All Implemented Interfaces:
Callable
,Function
,GroundedValue
,Item
,Sequence
This class supports the XPath function boolean()
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptioncall
(XPathContext c, Sequence[] arguments) Invoke the functionGet the (local) name of a class that can be used to generate bytecode for this system functionGet a name that identifies the class that can be used to evaluate this function in streaming mode, that is, supplying one item or event at a time as it is delivered by the parser.makeFunctionCall
(Expression[] arguments) Make an expression that either calls this function, or that is equivalent to a call on this functionstatic Expression
rewriteEffectiveBooleanValue
(Expression exp, ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) Optimize an expression whose effective boolean value is required.void
supplyTypeInformation
(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType, Expression[] arguments) Method called during static type checking.Methods inherited from class net.sf.saxon.functions.SystemFunction
dependsOnContextItem, dynamicCall, equals, export, exportAdditionalArguments, exportAttributes, fixArguments, getArity, getCardinality, getContextNode, getDescription, getDetails, getErrorCodeForTypeErrors, getFunctionItemType, getFunctionName, getIntegerBounds, getNetCost, getOperandRoles, getRequiredType, getResultItemType, getResultItemType, getRetainedStaticContext, getSpecialProperties, getStaticBaseUriString, importAttributes, isTrustedResultType, makeCall, makeFunction, makeOptimizedFunctionCall, resultIfEmpty, setArity, setDetails, setRetainedStaticContext, toShortString, toString, typeCheckCaller
Methods inherited from class net.sf.saxon.functions.AbstractFunction
atomize, deepEquals, effectiveBooleanValue, getAnnotations, getStringValue, getStringValueCS, isArray, isMap, makeNewContext, simplify, typeCheck
Methods inherited from class java.lang.Object
clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods inherited from interface net.sf.saxon.om.GroundedValue
asIterable, concatenate, containsNode, materialize
Methods inherited from interface net.sf.saxon.om.Item
getLength, head, isStreamed, itemAt, iterate, reduce, subsequence
Methods inherited from interface net.sf.saxon.om.Sequence
makeRepeatable
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Constructor Details
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BooleanFn
public BooleanFn()
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Method Details
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supplyTypeInformation
public void supplyTypeInformation(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType, Expression[] arguments) throws XPathException Description copied from class:SystemFunction
Method called during static type checking. This method may be implemented in subclasses so that functions can take advantage of knowledge of the types of the arguments that will be supplied.- Overrides:
supplyTypeInformation
in classSystemFunction
- Parameters:
visitor
- an expression visitor, providing access to the static context and configurationcontextItemType
- information about whether the context item is set, and what its type isarguments
- the expressions appearing as arguments in the function call- Throws:
XPathException
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rewriteEffectiveBooleanValue
public static Expression rewriteEffectiveBooleanValue(Expression exp, ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException Optimize an expression whose effective boolean value is required. It is appropriate to apply this rewrite to any expression whose value will be obtained by calling the Expression.effectiveBooleanValue() method (and not otherwise)- Parameters:
exp
- the expression whose EBV is to be evaluatedvisitor
- an expression visitorcontextItemType
- the type of the context item for this expression- Returns:
- an expression that returns the EBV of exp, or null if no optimization was possible
- Throws:
XPathException
- if static errors are found
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call
Description copied from interface:Function
Invoke the function- Parameters:
c
- the XPath dynamic evaluation contextarguments
- the actual arguments to be supplied- Returns:
- the result of invoking the function
- Throws:
XPathException
- if a dynamic error occurs within the function
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makeFunctionCall
Description copied from class:SystemFunction
Make an expression that either calls this function, or that is equivalent to a call on this function- Overrides:
makeFunctionCall
in classSystemFunction
- Parameters:
arguments
- the supplied arguments to the function call- Returns:
- either a function call on this function, or an expression that delivers the same result
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getCompilerName
Description copied from class:SystemFunction
Get the (local) name of a class that can be used to generate bytecode for this system function- Overrides:
getCompilerName
in classSystemFunction
- Returns:
- the name of a bytecode generation class, or null if there is no bytecode support for this function
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getStreamerName
Description copied from class:SystemFunction
Get a name that identifies the class that can be used to evaluate this function in streaming mode, that is, supplying one item or event at a time as it is delivered by the parser. Special streaming support is generally available in Saxon-EE for all system functions that take a sequence as their argument.- Overrides:
getStreamerName
in classSystemFunction
- Returns:
- a name that identifies a class that supports streamed evaluation of this system
function, or null if no such class is available. The mapping of names to classes is
defined in the Saxon-EE class
StreamerMap
. In non-streaming Saxon editions (HE and PE) the method always returns null.
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