Package net.sf.saxon.expr
Class NegateExpression
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.expr.UnaryExpression
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- net.sf.saxon.expr.NegateExpression
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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 NegateExpression extends UnaryExpression
Negate Expression: implements the unary minus operator. This expression is initially created as an ArithmeticExpression (or in backwards compatibility mode, an ArithmeticExpression10) to take advantage of the type checking code. So we don't need to worry about type checking or argument conversion.- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class net.sf.saxon.expr.UnaryExpression
operand
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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 NegateExpression(Expression base)
Create a NegateExpression
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Expression
copy()
Copy an expression.protected java.lang.String
displayOperator(Configuration config)
Give a string representation of the operator for use in diagnosticsItem
evaluateItem(XPathContext context)
Evaluate the expression.ItemType
getItemType(TypeHierarchy th)
Determine the data type of the expression, if this is known staticallyvoid
setBackwardsCompatible(boolean compatible)
Set whether the expression is to be evaluated in XPath 1.0 compatibility modeExpression
typeCheck(ExpressionVisitor visitor, ItemType contextItemType)
Type-check the expression.-
Methods inherited from class net.sf.saxon.expr.UnaryExpression
computeCardinality, computeSpecialProperties, displayExpressionName, equals, explain, getBaseExpression, hashCode, iterateSubExpressions, optimize, promote, replaceSubExpression, simplify, toString
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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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Constructor Detail
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NegateExpression
public NegateExpression(Expression base)
Create a NegateExpression- Parameters:
base
- the expression that computes the value whose sign is to be reversed
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Method Detail
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setBackwardsCompatible
public void setBackwardsCompatible(boolean compatible)
Set whether the expression is to be evaluated in XPath 1.0 compatibility mode- Parameters:
compatible
- true if XPath 1.0 compatibility mode is enabled
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
Description copied from class:UnaryExpression
Type-check the expression. Default implementation for unary operators that accept any kind of operand- Overrides:
typeCheck
in classUnaryExpression
- 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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getItemType
public ItemType getItemType(TypeHierarchy th)
Determine the data type of the expression, if this is known statically- Overrides:
getItemType
in classUnaryExpression
- Parameters:
th
- the type hierarchy cache- Returns:
- the item type of the items in the result sequence, insofar as this is known statically.
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evaluateItem
public Item evaluateItem(XPathContext context) throws XPathException
Evaluate the expression.- Specified by:
evaluateItem
in interfaceEvaluableItem
- 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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copy
public Expression copy()
Copy an expression. This makes a deep copy.- Specified by:
copy
in classExpression
- Returns:
- the copy of the original expression
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displayOperator
protected java.lang.String displayOperator(Configuration config)
Description copied from class:UnaryExpression
Give a string representation of the operator for use in diagnostics- Overrides:
displayOperator
in classUnaryExpression
- Returns:
- the operator, as a string
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