Package net.sf.saxon.functions
Class Minimax
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.expr.FunctionCall
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- net.sf.saxon.functions.SystemFunction
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- net.sf.saxon.functions.CollatingFunction
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- net.sf.saxon.functions.Minimax
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- All Implemented Interfaces:
java.io.Serializable,javax.xml.transform.SourceLocator,LocationProvider,SaxonLocator,EvaluableItem,SequenceIterable,InstructionInfo,org.xml.sax.Locator
public class Minimax extends CollatingFunction
This class implements the min() and max() functions- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description static intMAXstatic intMIN-
Fields inherited from class net.sf.saxon.functions.CollatingFunction
stringCollator
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Fields inherited from class net.sf.saxon.functions.SystemFunction
operation
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Fields inherited from class net.sf.saxon.expr.FunctionCall
argument
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Fields inherited from class net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
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Constructor Summary
Constructors Constructor Description Minimax()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description voidcheckArguments(ExpressionVisitor visitor)Static analysis: prevent sorting of the argumentintcomputeCardinality()Determine the cardinality of the function.ItemevaluateItem(XPathContext context)Evaluate the functionItemTypegetItemType(TypeHierarchy th)Determine the item type of the value returned by the functionbooleanisIgnoreNaN()Test whether NaN values are to be ignoredstatic AtomicValueminimax(SequenceIterator iter, int operation, AtomicComparer atomicComparer, boolean ignoreNaN, XPathContext context)Static method to evaluate the minimum or maximum of a sequenceExpressionoptimize(ExpressionVisitor visitor, ItemType contextItemType)Perform optimisation of an expression and its subexpressions.voidsetIgnoreNaN(boolean ignore)Indicate whether NaN values should be ignored.-
Methods inherited from class net.sf.saxon.functions.CollatingFunction
copy, getAtomicComparer, getCollator, getExpressionBaseURI, getStringCollator
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Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, addDocToPathMap, computeSpecialProperties, getDetails, getErrorCodeForTypeErrors, getRequiredType, makeSystemFunction, setDetails, useContextItemAsDefault
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Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, checkArgumentCount, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck
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Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterate, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
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Field Detail
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MIN
public static final int MIN
- See Also:
- Constant Field Values
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MAX
public static final int MAX
- See Also:
- Constant Field Values
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Method Detail
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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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checkArguments
public void checkArguments(ExpressionVisitor visitor) throws XPathException
Static analysis: prevent sorting of the argument- Overrides:
checkArgumentsin classCollatingFunction- Parameters:
visitor- the expression visitor- Throws:
XPathException
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computeCardinality
public int computeCardinality()
Determine the cardinality of the function.- Overrides:
computeCardinalityin 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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optimize
public Expression optimize(ExpressionVisitor visitor, ItemType 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:
optimizein 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
public ItemType getItemType(TypeHierarchy th)
Determine the item type of the value returned by the function- Overrides:
getItemTypein classSystemFunction- Parameters:
th- the type hierarchy cache- Returns:
- the statically inferred type of the expression
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evaluateItem
public Item evaluateItem(XPathContext context) throws XPathException
Evaluate the function- Specified by:
evaluateItemin interfaceEvaluableItem- Overrides:
evaluateItemin 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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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- eitherMINorMAXatomicComparer- 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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