Package net.sf.saxon.functions
Class Subsequence
- 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.Subsequence
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,LocationProvider
,SaxonLocator
,CallableExpression
,InstructionInfo
,org.xml.sax.Locator
public class Subsequence extends SystemFunction implements CallableExpression
Implements the XPath 2.0 subsequence() function- See Also:
- Serialized Form
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Field Summary
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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
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 Constructor Description Subsequence()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description SequenceIterator
call(SequenceIterator[] arguments, XPathContext context)
Evaluate the expressionint
computeCardinality()
Determine the cardinality of the function.int
computeSpecialProperties()
Get the static properties of this expression (other than its type).ItemType
getItemType(TypeHierarchy th)
Determine the data type of the items in the sequenceSequenceIterator
iterate(XPathContext context)
Evaluate the function to return an iteration of selected nodes.Expression
optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions.static SequenceIterator
subSequence(SequenceIterator seq, NumericValue startVal, NumericValue lengthVal, XPathContext context)
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Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, addDocToPathMap, checkArguments, copy, equals, getDetails, getErrorCodeForTypeErrors, getImplementationMethod, getOperation, getRequiredType, makeSystemFunction, setDetails, useContextItemAsDefault
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Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, 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, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface net.sf.saxon.expr.CallableExpression
getArguments
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Method Detail
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getItemType
public ItemType getItemType(TypeHierarchy th)
Determine the data type of the items in the sequence- Overrides:
getItemType
in classSystemFunction
- Parameters:
th
- the type hierarchy cache- Returns:
- the type of the argument
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computeSpecialProperties
public int computeSpecialProperties()
Get the static properties of this expression (other than its type). The result is bit-significant. 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 classSystemFunction
- Returns:
- the special properties, as a bit-significant integer
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computeCardinality
public int computeCardinality()
Determine the cardinality of the function.- Overrides:
computeCardinality
in 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, ExpressionVisitor.ContextItemType 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:
optimize
in 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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iterate
public SequenceIterator iterate(XPathContext context) throws XPathException
Evaluate the function to return an iteration of selected nodes.- Overrides:
iterate
in classExpression
- 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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call
public SequenceIterator call(SequenceIterator[] arguments, XPathContext context) throws XPathException
Description copied from interface:CallableExpression
Evaluate the expression- Specified by:
call
in interfaceCallableExpression
- Parameters:
arguments
- the values of the arguments, supplied as SequenceIteratorscontext
- the dynamic evaluation context- Returns:
- the result of the evaluation, in the form of a SequenceIterator
- Throws:
XPathException
- if a dynamic error occurs during the evaluation of the expression
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subSequence
public static SequenceIterator subSequence(SequenceIterator seq, NumericValue startVal, NumericValue lengthVal, XPathContext context) throws XPathException
- Throws:
XPathException
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