Package net.sf.saxon.sort
Class Reverser
- java.lang.Object
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- net.sf.saxon.expr.ComputedExpression
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- net.sf.saxon.expr.UnaryExpression
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- net.sf.saxon.sort.Reverser
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,Container
,Expression
,InstructionInfoProvider
public class Reverser extends UnaryExpression
A Reverser is an expression that reverses the order of a sequence of items.- 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.ComputedExpression
locationId, staticProperties
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Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
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Constructor Summary
Constructors Constructor Description Reverser(Expression base)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
computeSpecialProperties()
Get the static properties of this expression (other than its type).protected java.lang.String
displayOperator(Configuration config)
Give a string representation of the operator for use in diagnosticsboolean
effectiveBooleanValue(XPathContext context)
Get the effective boolean value of the expression.SequenceIterator
iterate(XPathContext context)
Return an Iterator to iterate over the values of a sequence.Expression
promote(PromotionOffer offer)
Promote this expression if possible-
Methods inherited from class net.sf.saxon.expr.UnaryExpression
computeCardinality, display, equals, getBaseExpression, getItemType, hashCode, iterateSubExpressions, optimize, replaceSubExpression, simplify, typeCheck
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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 Detail
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Reverser
public Reverser(Expression base)
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Method Detail
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computeSpecialProperties
public int computeSpecialProperties()
Description copied from class:UnaryExpression
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 classUnaryExpression
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promote
public Expression promote(PromotionOffer offer) throws XPathException
Promote this expression if possible- Specified by:
promote
in interfaceExpression
- Overrides:
promote
in classUnaryExpression
- Parameters:
offer
- details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression- Returns:
- if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression
- Throws:
XPathException
- if any error is detected
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iterate
public SequenceIterator iterate(XPathContext context) throws XPathException
Description copied from class:ComputedExpression
Return an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.- Specified by:
iterate
in interfaceExpression
- Overrides:
iterate
in classComputedExpression
- Parameters:
context
- supplies the context for evaluation- Returns:
- a SequenceIterator that can be used to iterate over the result of the expression
- Throws:
XPathException
- if any dynamic error occurs evaluating the expression
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effectiveBooleanValue
public boolean effectiveBooleanValue(XPathContext context) throws XPathException
Description copied from class:ComputedExpression
Get the effective boolean value of the expression. This returns false if the value is the empty sequence, a zero-length string, a number equal to zero, or the boolean false. Otherwise it returns true.- 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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displayOperator
protected java.lang.String displayOperator(Configuration config)
Give a string representation of the operator for use in diagnostics- Specified by:
displayOperator
in classUnaryExpression
- Parameters:
config
-- Returns:
- the operator, as a string
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