Package net.sf.saxon.functions
Class Minimax
java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.functions.SystemFunction
net.sf.saxon.functions.CollatingFunction
net.sf.saxon.functions.Minimax
- All Implemented Interfaces:
Serializable
,SourceLocator
,LocationProvider
,SaxonLocator
,InstructionInfo
,Locator
This class implements the min() and max() functions
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Field Summary
FieldsFields inherited from class net.sf.saxon.functions.CollatingFunction
stringCollator
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
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
checkArguments
(ExpressionVisitor visitor) Static analysis: prevent sorting of the argumentint
Determine the cardinality of the function.copy()
Copy an expression.boolean
Determine whether two expressions are equivalentevaluateItem
(XPathContext context) Evaluate the functiongetAtomicComparer
(XPathContext context) int
Get implementation methodDetermine the item type of the value returned by the functionboolean
Test whether NaN values are to be ignoredstatic AtomicValue
minimax
(SequenceIterator iter, int operation, AtomicComparer atomicComparer, boolean ignoreNaN, XPathContext context) Static method to evaluate the minimum or maximum of a sequenceoptimize
(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) Perform optimisation of an expression and its subexpressions.void
setIgnoreNaN
(boolean ignore) Indicate whether NaN values should be ignored.typeCheck
(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) Type-check the expressionMethods inherited from class net.sf.saxon.functions.CollatingFunction
expandCollationURI, getAbsoluteCollationURI, getAtomicComparer, getCollator, getExpressionBaseURI, getStringCollator
Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, addDocToPathMap, computeSpecialProperties, getDetails, getErrorCodeForTypeErrors, getOperation, getRequiredType, makeSystemFunction, setDetails, useContextItemAsDefault
Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
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Field Details
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MIN
public static final int MIN- See Also:
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MAX
public static final int MAX- See Also:
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Constructor Details
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Minimax
public Minimax()
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Method Details
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setIgnoreNaN
public void setIgnoreNaN(boolean ignore) Indicate whether NaN values should be ignored. For the external min() and max() function, a NaN value in the input causes the result to be NaN. Internally, however, min() and max() are also used in such a way that NaN values should be ignored.- Parameters:
ignore
- true if NaN values are to be ignored when computing the min or max.
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isIgnoreNaN
public boolean isIgnoreNaN()Test whether NaN values are to be ignored- Returns:
- true if NaN values are to be ignored. This is the case for internally-generated min() and max() functions used to support general comparisons
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getComparer
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getArgumentType
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getImplementationMethod
public int getImplementationMethod()Get implementation method- Overrides:
getImplementationMethod
in classSystemFunction
- Returns:
- a value that indicates this function is capable of being streamed
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checkArguments
Static analysis: prevent sorting of the argument- Overrides:
checkArguments
in classCollatingFunction
- Parameters:
visitor
- the expression visitor- Throws:
XPathException
- if the arguments are incorrect
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computeCardinality
public int computeCardinality()Determine the cardinality of the function.- Overrides:
computeCardinality
in classSystemFunction
- Returns:
- the computed cardinality, as one of the values
StaticProperty.ALLOWS_ZERO_OR_ONE
,StaticProperty.EXACTLY_ONE
,StaticProperty.ALLOWS_ONE_OR_MORE
,StaticProperty.ALLOWS_ZERO_OR_MORE
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException Type-check the expression- Overrides:
typeCheck
in 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)
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optimize
public Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException Perform optimisation of an expression and its subexpressions.This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.
- Overrides:
optimize
in classSystemFunction
- 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 if appropriate to optimize execution
- Throws:
XPathException
- if an error is discovered during this phase (typically a type error)
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getItemType
Determine the item type of the value returned by the function- Overrides:
getItemType
in classSystemFunction
- Parameters:
th
- the type hierarchy cache- Returns:
- the statically inferred type of the expression
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copy
Copy an expression. This makes a deep copy.- Overrides:
copy
in classCollatingFunction
- Returns:
- the copy of the original expression
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equals
Determine whether two expressions are equivalent- Overrides:
equals
in classCollatingFunction
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evaluateItem
Evaluate the function- Overrides:
evaluateItem
in classExpression
- 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
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getAtomicComparer
- Throws:
XPathException
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minimax
public static AtomicValue minimax(SequenceIterator iter, int operation, AtomicComparer atomicComparer, boolean ignoreNaN, XPathContext context) throws XPathException Static method to evaluate the minimum or maximum of a sequence- Parameters:
iter
- Iterator over the input sequenceoperation
- eitherMIN
orMAX
atomicComparer
- an AtomicComparer used to compare valuesignoreNaN
- true if NaN values are to be ignoredcontext
- dynamic evaluation context- Returns:
- the min or max value in the sequence, according to the rules of the fn:min() or fn:max() functions
- Throws:
XPathException
- typically if non-comparable values are found in the sequence
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