Package net.sf.saxon.pattern
Class VennPattern
- java.lang.Object
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- net.sf.saxon.pattern.Pattern
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- net.sf.saxon.pattern.VennPattern
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,Container
,PatternFinder
- Direct Known Subclasses:
ExceptPattern
,IntersectPattern
,UnionPattern
public abstract class VennPattern extends Pattern
A pattern formed as the union, intersection, or difference of two other patterns- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description VennPattern(Pattern p1, Pattern p2)
Constructor
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
allocateSlots(StaticContext env, SlotManager slotManager, int nextFree)
Allocate slots to any variables used within the patternPattern
analyze(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)
Type-check the pattern.protected void
bindVariable(Item item, XPathContext context)
boolean
equals(java.lang.Object other)
Determine whether this pattern is the same as another patternvoid
gatherComponentPatterns(java.util.Set set)
Gather the component (non-Venn) patterns of this Venn patternint
getDependencies()
Get the dependencies of the pattern.ItemType
getItemType()
Get an ItemType that all the items matching this pattern must satisfyPattern
getLHS()
Get the LHS of the unionint
getNodeKind()
Determine the types of nodes to which this pattern applies.Pattern
getRHS()
Get the RHS of the unionExpression
getVariableBindingExpression()
int
hashCode()
Hashcode supporting equals()java.util.Iterator
iterateSubExpressions()
Iterate over the subexpressions within this patternvoid
promote(PromotionOffer offer, Expression parent)
Offer promotion for subexpressions within this pattern.boolean
replaceSubExpression(Expression original, Expression replacement)
Replace a subexpression by a replacement subexpressionvoid
resolveCurrent(LetExpression let, PromotionOffer offer, boolean topLevel)
If the pattern contains any calls on current(), this method is called to modify such calls to become variable references to a variable declared in a specially-allocated local variablevoid
setExecutable(Executable executable)
Set the executable containing this patternvoid
setLineNumber(int lineNumber)
Override method to set the system ID, so it's set on both halvesvoid
setOriginalText(java.lang.String pattern)
Set the original textvoid
setSystemId(java.lang.String systemId)
Override method to set the system ID, so it's set on both halvesvoid
setVariableBindingExpression(Expression exp)
Set an expression used to bind the variable that represents the value of the current() functionPattern
simplify(ExpressionVisitor visitor)
Simplify the pattern: perform any context-independent optimisations-
Methods inherited from class net.sf.saxon.pattern.Pattern
getColumnNumber, getContainerGranularity, getDefaultPriority, getExecutable, getFingerprint, getHostLanguage, getLineNumber, getLocationProvider, getPublicId, getSystemId, internalMatches, make, matches, matchesBeneathAnchor, selectNodes, toString
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Method Detail
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setExecutable
public void setExecutable(Executable executable)
Set the executable containing this pattern- Overrides:
setExecutable
in classPattern
- Parameters:
executable
- the executable
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simplify
public Pattern simplify(ExpressionVisitor visitor) throws XPathException
Simplify the pattern: perform any context-independent optimisations- Overrides:
simplify
in classPattern
- Parameters:
visitor
- an expression visitor- Returns:
- the optimised Pattern
- Throws:
XPathException
- if a static error is discovered
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analyze
public Pattern analyze(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
Type-check the pattern. This is only needed for patterns that contain variable references or function calls.- Overrides:
analyze
in classPattern
- Parameters:
visitor
- the expression visitorcontextItemType
- the type of the context item at the point where the pattern is defined. Set to null if it is known that the context item is undefined.- Returns:
- the optimised Pattern
- Throws:
XPathException
- if a static error is discovered
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resolveCurrent
public void resolveCurrent(LetExpression let, PromotionOffer offer, boolean topLevel) throws XPathException
If the pattern contains any calls on current(), this method is called to modify such calls to become variable references to a variable declared in a specially-allocated local variable- Overrides:
resolveCurrent
in classPattern
- Parameters:
let
- the expression that assigns the local variable. This returns a dummy result, and is executed just before evaluating the pattern, to get the value of the context item into the variable.offer
- A PromotionOffer used to process the expressions and change the call on current() into a variable referencetopLevel
-- Throws:
XPathException
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promote
public void promote(PromotionOffer offer, Expression parent) throws XPathException
Offer promotion for subexpressions within this pattern. 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.Unlike the corresponding method on
Expression
, this method does not return anything: it can make internal changes to the pattern, but cannot return a different pattern. Only certain kinds of promotion are applicable within a pattern: specifically, promotions affecting local variable references within the pattern.- Overrides:
promote
in classPattern
- 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 expressionparent
-- Throws:
XPathException
- if any error is detected
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replaceSubExpression
public boolean replaceSubExpression(Expression original, Expression replacement)
Replace a subexpression by a replacement subexpression- Overrides:
replaceSubExpression
in classPattern
- Parameters:
original
- the expression to be replacedreplacement
- the new expression to be inserted in its place- Returns:
- true if the replacement was carried out
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setOriginalText
public void setOriginalText(java.lang.String pattern)
Set the original text- Overrides:
setOriginalText
in classPattern
- Parameters:
pattern
- the original text of the pattern
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allocateSlots
public int allocateSlots(StaticContext env, SlotManager slotManager, int nextFree)
Allocate slots to any variables used within the pattern- Overrides:
allocateSlots
in classPattern
- Parameters:
env
- the static context in the XSLT stylesheetslotManager
-nextFree
- the next slot that is free to be allocated @return the next slot that is free to be allocated- Returns:
- the next slot that is free to be allocated
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setVariableBindingExpression
public void setVariableBindingExpression(Expression exp)
Set an expression used to bind the variable that represents the value of the current() function- Overrides:
setVariableBindingExpression
in classPattern
- Parameters:
exp
- the expression that binds the variable
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getVariableBindingExpression
public Expression getVariableBindingExpression()
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gatherComponentPatterns
public void gatherComponentPatterns(java.util.Set set)
Gather the component (non-Venn) patterns of this Venn pattern- Parameters:
set
- the set into which the components will be added
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getNodeKind
public int getNodeKind()
Determine the types of nodes to which this pattern applies. Used for optimisation. For patterns that match nodes of several types, return Node.NODE- Overrides:
getNodeKind
in classPattern
- Returns:
- the type of node matched by this pattern. e.g. Node.ELEMENT or Node.TEXT
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getItemType
public ItemType getItemType()
Get an ItemType that all the items matching this pattern must satisfy- Specified by:
getItemType
in classPattern
- Returns:
- an ItemType, as specific as possible, which all the matching items satisfy
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getDependencies
public int getDependencies()
Get the dependencies of the pattern. The only possible dependency for a pattern is on local variables. This is analyzed in those patterns where local variables may appear.- Overrides:
getDependencies
in classPattern
- Returns:
- the dependencies, as a bit-significant mask
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iterateSubExpressions
public java.util.Iterator iterateSubExpressions()
Iterate over the subexpressions within this pattern- Overrides:
iterateSubExpressions
in classPattern
- Returns:
- an iterator over the subexpressions.
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bindVariable
protected void bindVariable(Item item, XPathContext context) throws XPathException
- Throws:
XPathException
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getLHS
public Pattern getLHS()
Get the LHS of the union- Returns:
- the first operand of the union
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getRHS
public Pattern getRHS()
Get the RHS of the union- Returns:
- the second operand of the union
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setSystemId
public void setSystemId(java.lang.String systemId)
Override method to set the system ID, so it's set on both halves- Overrides:
setSystemId
in classPattern
- Parameters:
systemId
- the URI of the module containing the pattern
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setLineNumber
public void setLineNumber(int lineNumber)
Override method to set the system ID, so it's set on both halves- Overrides:
setLineNumber
in classPattern
- Parameters:
lineNumber
- the line number of the pattern in the source module
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equals
public boolean equals(java.lang.Object other)
Determine whether this pattern is the same as another pattern- Overrides:
equals
in classjava.lang.Object
- Parameters:
other
- the other object
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hashCode
public int hashCode()
Hashcode supporting equals()- Overrides:
hashCode
in classjava.lang.Object
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