Package net.sf.saxon.pattern
Class LocationPathPattern
- java.lang.Object
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- net.sf.saxon.pattern.Pattern
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- net.sf.saxon.pattern.LocationPathPattern
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,Container
,PatternFinder
public final class LocationPathPattern extends Pattern
A LocationPathPattern represents a path, for example of the form A/B/C... The components are represented as a linked list, each component pointing to its predecessor- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description Pattern
ancestorPattern
protected Expression
equivalentExpr
protected Expression[]
filters
protected boolean
firstElementPattern
protected boolean
lastElementPattern
NodeTest
nodeTest
protected int
numberOfFilters
Pattern
parentPattern
protected boolean
specialFilter
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Constructor Summary
Constructors Constructor Description LocationPathPattern()
Create a LocationPathPattern
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
addFilter(Expression filter)
Add a filter to the pattern (while under construction)int
allocateSlots(StaticContext env, SlotManager slotManager, int nextFree)
Allocate slots to any variables used within the patternPattern
analyze(ExpressionVisitor visitor, ItemType contextItemType)
Type-check the pattern, performing any type-dependent optimizations.boolean
equals(java.lang.Object other)
Determine whether this pattern is the same as another patternPattern
getAncestorPattern()
Get the pattern applying to an ancestor node, if there is oneint
getDependencies()
Get the dependencies of the pattern.Expression[]
getFilters()
Get the filters assocated with the last step in the patternint
getFingerprint()
Determine the fingerprint of nodes to which this pattern applies.int
getNodeKind()
Determine the types of nodes to which this pattern applies.NodeTest
getNodeTest()
Get a NodeTest that all the nodes matching this pattern must satisfyPattern
getParentPattern()
Get the pattern applying to the parent node, if there is oneint
hashCode()
Hashcode supporting equals()protected boolean
internalMatches(NodeInfo node, XPathContext context)
Test whether the pattern matches, but without changing the current() nodejava.util.Iterator
iterateSubExpressions()
Iterate over the subexpressions within this patternboolean
matches(NodeInfo node, XPathContext context)
Determine whether the pattern matches a given node.void
promote(PromotionOffer offer)
Offer promotion for subexpressions within this pattern.boolean
replaceSubExpression(Expression original, Expression replacement)
Replace one 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 patternPattern
simplify(ExpressionVisitor visitor)
Simplify the pattern: perform any context-independent optimisations-
Methods inherited from class net.sf.saxon.pattern.Pattern
getColumnNumber, getDefaultPriority, getExecutable, getHostLanguage, getLineNumber, getLocationProvider, getPublicId, getSystemId, make, makeSearchExpression, selectNodes, setLineNumber, setOriginalText, setSystemId, toString
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Field Detail
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parentPattern
public Pattern parentPattern
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ancestorPattern
public Pattern ancestorPattern
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nodeTest
public NodeTest nodeTest
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filters
protected Expression[] filters
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numberOfFilters
protected int numberOfFilters
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equivalentExpr
protected Expression equivalentExpr
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firstElementPattern
protected boolean firstElementPattern
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lastElementPattern
protected boolean lastElementPattern
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specialFilter
protected boolean specialFilter
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Method Detail
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addFilter
public void addFilter(Expression filter)
Add a filter to the pattern (while under construction)- Parameters:
filter
- The predicate (a boolean expression or numeric expression) to be added
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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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getFilters
public Expression[] getFilters()
Get the filters assocated with the last step in the pattern- Returns:
- an array of expression holding the filter predicates in order
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getParentPattern
public Pattern getParentPattern()
Get the pattern applying to the parent node, if there is one- Returns:
- the parent pattern, for example if the pattern is a/b[1]/c then the parent pattern is a/b[1]
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getAncestorPattern
public Pattern getAncestorPattern()
Get the pattern applying to an ancestor node, if there is one- Returns:
- the ancestor pattern, for example if the pattern is a/b[1]//c then the ancestor pattern is a/b[1]
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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
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analyze
public Pattern analyze(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
Type-check the pattern, performing any type-dependent optimizations.- Overrides:
analyze
in classPattern
- Parameters:
visitor
- an expression visitorcontextItemType
- the type of the context item at the point where the pattern appears- Returns:
- the optimised Pattern
- Throws:
XPathException
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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. Default implementation returns an empty sequence
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replaceSubExpression
public boolean replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpression- Specified by:
replaceSubExpression
in interfaceContainer
- Overrides:
replaceSubExpression
in classPattern
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression- Returns:
- true if the original subexpression is found
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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
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promote
public void promote(PromotionOffer offer) 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 expression- Throws:
XPathException
- if any error is detected
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matches
public boolean matches(NodeInfo node, XPathContext context) throws XPathException
Determine whether the pattern matches a given node.- Specified by:
matches
in classPattern
- Parameters:
node
- the node to be testedcontext
- The dynamic context. Only relevant if the pattern uses variables, or contains calls on functions such as document() or key().- Returns:
- true if the pattern matches, else false
- Throws:
XPathException
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internalMatches
protected boolean internalMatches(NodeInfo node, XPathContext context) throws XPathException
Test whether the pattern matches, but without changing the current() node- Overrides:
internalMatches
in classPattern
- Parameters:
node
- The NodeInfo representing the Element or other node to be tested against the Patterncontext
- The dynamic context. Only relevant if the pattern uses variables, or contains calls on functions such as document() or key().- Returns:
- true if the node matches the Pattern, false otherwise
- Throws:
XPathException
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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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getFingerprint
public int getFingerprint()
Determine the fingerprint of nodes to which this pattern applies. Used for optimisation.- Overrides:
getFingerprint
in classPattern
- Returns:
- the fingerprint of nodes matched by this pattern.
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getNodeTest
public NodeTest getNodeTest()
Get a NodeTest that all the nodes matching this pattern must satisfy- Specified by:
getNodeTest
in classPattern
- Returns:
- a NodeTest, as specific as possible, which all the matching nodes satisfy
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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- 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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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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