Package net.sf.saxon.expr
Class NegateExpression
java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.UnaryExpression
net.sf.saxon.expr.NegateExpression
- All Implemented Interfaces:
Serializable
,SourceLocator
,LocationProvider
,SaxonLocator
,InstructionInfo
,Locator
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:
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Field Summary
Fields inherited from class net.sf.saxon.expr.UnaryExpression
operand
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 TypeMethodDescriptioncopy()
Copy an expression.protected String
displayOperator
(Configuration config) Give a string representation of the operator for use in diagnosticsevaluateItem
(XPathContext context) Evaluate the expression.Get a name identifying the kind of expression, in terms meaningful to a user.Determine the data type of the expression, if this is known staticallyboolean
Ask whether the expression is to be evaluated in XPath 1.0 compatibility modevoid
setBackwardsCompatible
(boolean compatible) Set whether the expression is to be evaluated in XPath 1.0 compatibility modetypeCheck
(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) Type-check the expression.Methods inherited from class net.sf.saxon.expr.UnaryExpression
computeCardinality, computeSpecialProperties, equals, explain, getBaseExpression, hashCode, iterateSubExpressions, optimize, promote, replaceSubExpression, simplify, 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, getImplementationMethod, 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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Constructor Details
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NegateExpression
Create a NegateExpression- Parameters:
base
- the expression that computes the value whose sign is to be reversed
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Method Details
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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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isBackwardsCompatible
public boolean isBackwardsCompatible()Ask whether the expression is to be evaluated in XPath 1.0 compatibility mode- Returns:
- true if XPath 1.0 compatibility mode is enabled
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType 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
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
Evaluate the expression.- 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
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
Description copied from class:UnaryExpression
Give a string representation of the operator for use in diagnostics- Overrides:
displayOperator
in classUnaryExpression
- Parameters:
config
- the Saxon configuration- Returns:
- the operator, as a string
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getExpressionName
Get a name identifying the kind of expression, in terms meaningful to a user.- Overrides:
getExpressionName
in classExpression
- Returns:
- a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.
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