Class NumberInstruction
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.instruct.NumberInstruction
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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 NumberInstruction extends Expression
An xsl:number element in the stylesheet. Although this is an XSLT instruction, it is compiled into an expression, evaluated using xsl:value-of to create the resulting text node.- See Also:
- Serialized Form
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Field Summary
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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 NumberInstruction(Configuration config, Expression select, int level, Pattern count, Pattern from, Expression value, Expression format, Expression groupSize, Expression groupSeparator, Expression letterValue, Expression ordinal, Expression lang, NumberFormatter formatter, Numberer numberer, boolean hasVariablesInPatterns, boolean backwardsCompatible)
Construct a NumberInstruction
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description int
computeCardinality()
Compute the static cardinality of this expressionExpression
copy()
Copy an expression.Item
evaluateItem(XPathContext context)
Evaluate an expression as a single item.void
explain(ExpressionPresenter out)
Diagnostic print of expression structure.int
getIntrinsicDependencies()
Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.ItemType
getItemType(TypeHierarchy th)
Determine the data type of the expression, if possible.java.util.Iterator
iterateSubExpressions()
Get the immediate sub-expressions of this expression.static Numberer
makeNumberer(java.lang.String language, java.lang.String country, XPathContext context)
Load a Numberer class for a given language and check it is OK.Expression
optimize(ExpressionVisitor visitor, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.Expression
promote(PromotionOffer offer)
Offer promotion for this subexpression.boolean
replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpressionExpression
simplify(ExpressionVisitor visitor)
Simplify an expression.Expression
typeCheck(ExpressionVisitor visitor, ItemType contextItemType)
Perform static analysis of an expression and its subexpressions.-
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, 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, toString, typeError
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Constructor Detail
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NumberInstruction
public NumberInstruction(Configuration config, Expression select, int level, Pattern count, Pattern from, Expression value, Expression format, Expression groupSize, Expression groupSeparator, Expression letterValue, Expression ordinal, Expression lang, NumberFormatter formatter, Numberer numberer, boolean hasVariablesInPatterns, boolean backwardsCompatible)
Construct a NumberInstruction- Parameters:
config
- the Saxon configurationselect
- the expression supplied in the select attributelevel
- one of "single", "level", "multi"count
- the pattern supplied in the count attributefrom
- the pattern supplied in the from attributevalue
- the expression supplied in the value attributeformat
- the expression supplied in the format attributegroupSize
- the expression supplied in the group-size attributegroupSeparator
- the expression supplied in the grouping-separator attributeletterValue
- the expression supplied in the letter-value attributeordinal
- the expression supplied in the ordinal attributelang
- the expression supplied in the lang attributeformatter
- A NumberFormatter to be usednumberer
- A Numberer to be used for localizationhasVariablesInPatterns
- true if one or more of the patterns contains variable referencesbackwardsCompatible
- true if running in 1.0 compatibility mode
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Method Detail
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simplify
public Expression simplify(ExpressionVisitor visitor) throws XPathException
Description copied from class:Expression
Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation does nothing.- Overrides:
simplify
in classExpression
- Parameters:
visitor
- an expression visitor- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
Perform static analysis of an expression and its subexpressions.This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables will only be accurately known if they have been explicitly declared.
- Overrides:
typeCheck
in classExpression
- 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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optimize
public Expression optimize(ExpressionVisitor visitor, ItemType 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 classExpression
- 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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iterateSubExpressions
public java.util.Iterator iterateSubExpressions()
Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.- Overrides:
iterateSubExpressions
in classExpression
- Returns:
- an iterator containing the sub-expressions of this 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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replaceSubExpression
public boolean replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpression- Overrides:
replaceSubExpression
in classExpression
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression- Returns:
- true if the original subexpression is found
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getIntrinsicDependencies
public int getIntrinsicDependencies()
Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".- Overrides:
getIntrinsicDependencies
in classExpression
- Returns:
- a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
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getItemType
public ItemType getItemType(TypeHierarchy th)
Description copied from class:Expression
Determine the data type of the expression, if possible. All expression return sequences, in general; this method determines the type of the items within the sequence, assuming that (a) this is known in advance, and (b) it is the same for all items in the sequence.This method should always return a result, though it may be the best approximation that is available at the time.
- Specified by:
getItemType
in classExpression
- Parameters:
th
- the type hierarchy cache- Returns:
- a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)
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computeCardinality
public int computeCardinality()
Description copied from class:Expression
Compute the static cardinality of this expression- Specified by:
computeCardinality
in classExpression
- 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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promote
public Expression promote(PromotionOffer offer) throws XPathException
Offer promotion for this subexpression. The offer will be accepted if the subexpression is not dependent on the factors (e.g. the context item) identified in the PromotionOffer. By default the offer is not accepted - this is appropriate in the case of simple expressions such as constant values and variable references where promotion would give no performance advantage. This method is always called at compile time.- Overrides:
promote
in classExpression
- 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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evaluateItem
public Item evaluateItem(XPathContext context) throws XPathException
Description copied from class:Expression
Evaluate an expression as a single item. This always returns either a single Item or null (denoting the empty sequence). No conversion is done. This method should not be used unless the static type of the expression is a subtype of "item" or "item?": that is, it should not be called if the expression may return a sequence. There is no guarantee that this condition will be detected.- 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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makeNumberer
public static Numberer makeNumberer(java.lang.String language, java.lang.String country, XPathContext context)
Load a Numberer class for a given language and check it is OK.- Parameters:
language
- the language for which a Numberer is requiredcountry
- the country for which a Numberer is requiredcontext
- XPath dynamic evaluation context- Returns:
- a suitable numberer. If no specific numberer is available for the language, the default (English) numberer is used.
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explain
public void explain(ExpressionPresenter out)
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Specified by:
explain
in classExpression
- Parameters:
out
- the expression presenter used to display the structure
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