Package net.sf.saxon.expr
Class VennExpression
java.lang.Object
net.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.BinaryExpression
net.sf.saxon.expr.VennExpression
- All Implemented Interfaces:
Serializable
,SourceLocator
,Container
,Expression
,InstructionInfoProvider
An expression representing a nodeset that is a union, difference, or
intersection of two other NodeSets
- See Also:
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Field Summary
Fields inherited from class net.sf.saxon.expr.BinaryExpression
operand0, operand1, operator
Fields inherited from class net.sf.saxon.expr.ComputedExpression
locationId, staticProperties
Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionfinal int
Determine the static cardinality of the expressionint
Get the static properties of this expression (other than its type).boolean
effectiveBooleanValue
(XPathContext context) Get the effective boolean value.final ItemType
Determine the data type of the items returned by this expressionint
hashCode()
Is this expression the same as another expression?Iterate over the value of the expression.simplify
(StaticContext env) Simplify the expressiontypeCheck
(StaticContext env, ItemType contextItemType) Type-check the expressionMethods inherited from class net.sf.saxon.expr.BinaryExpression
display, displayOperator, equals, getOperands, getOperator, isAssociative, isCommutative, isInverse, iterateSubExpressions, optimize, promote, replaceSubExpression
Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, evaluateAsString, evaluateItem, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation, typeError
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Constructor Details
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VennExpression
Constructor- Parameters:
p1
- the left-hand operandop
- the operator (union, intersection, or difference)p2
- the right-hand operand
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Method Details
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getItemType
Determine the data type of the items returned by this expression- Parameters:
th
-- Returns:
- the data type
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computeCardinality
public final int computeCardinality()Determine the static cardinality of the expression- Overrides:
computeCardinality
in classBinaryExpression
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computeSpecialProperties
public int computeSpecialProperties()Get the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.- Overrides:
computeSpecialProperties
in classBinaryExpression
- Returns:
StaticProperty.NON_CREATIVE
. This is overridden for some subclasses.
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simplify
Simplify the expression- Specified by:
simplify
in interfaceExpression
- Overrides:
simplify
in classBinaryExpression
- Parameters:
env
- the static context- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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typeCheck
Type-check the expression- Specified by:
typeCheck
in interfaceExpression
- Overrides:
typeCheck
in classBinaryExpression
- Parameters:
env
- the static context of the expressioncontextItemType
- 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
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hashCode
public int hashCode()Is this expression the same as another expression?- Overrides:
hashCode
in classBinaryExpression
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iterate
Iterate over the value of the expression. The result will always be sorted in document order, with duplicates eliminated- Specified by:
iterate
in interfaceExpression
- Overrides:
iterate
in classComputedExpression
- Parameters:
c
- The context for evaluation- Returns:
- a SequenceIterator representing the union of the two operands
- Throws:
XPathException
- if any dynamic error occurs evaluating the expression
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effectiveBooleanValue
Get the effective boolean value. In the case of a union expression, this is reduced to an OR expression, for efficiency- Specified by:
effectiveBooleanValue
in interfaceExpression
- Overrides:
effectiveBooleanValue
in classComputedExpression
- Parameters:
context
- The context in which the expression is to be evaluated- Returns:
- the effective boolean value
- Throws:
XPathException
- if any dynamic error occurs evaluating the expression
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