net.sf.saxon.pattern
Class LocationPathPattern
- Container, PatternFinder, Serializable, SourceLocator
public final class LocationPathPattern
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
void | addFilter(Expression filter) - Add a filter to the pattern (while under construction)
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int | allocateSlots(ExpressionContext env, int nextFree) - Allocate slots to any variables used within the pattern
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Pattern | analyze(ExpressionVisitor visitor, ItemType contextItemType) - Type-check the pattern, performing any type-dependent optimizations.
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Pattern | getAncestorPattern() - Get the pattern applying to an ancestor node, if there is one
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int | getDependencies() - Get the dependencies of the pattern.
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Expression[] | getFilters() - Get the filters assocated with the last step in the pattern
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int | getFingerprint() - Determine the fingerprint of nodes to which this pattern applies.
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int | getNodeKind() - Determine the types of nodes to which this pattern applies.
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NodeTest | getNodeTest() - Get a NodeTest that all the nodes matching this pattern must satisfy
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Pattern | getParentPattern() - Get the pattern applying to the parent node, if there is one
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protected boolean | internalMatches(NodeInfo node, XPathContext context) - Test whether the pattern matches, but without changing the current() node
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Iterator | iterateSubExpressions() - Iterate over the subexpressions within this pattern
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boolean | matches(NodeInfo node, XPathContext context) - Determine whether the pattern matches a given node.
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void | promote(PromotionOffer offer) - Offer promotion for subexpressions within this pattern.
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boolean | replaceSubExpression(Expression original, Expression replacement) - Replace one subexpression by a replacement subexpression
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void | resolveCurrent(LetExpression let, PromotionOffer offer) - 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
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void | setExecutable(Executable executable) - Set the executable containing this pattern
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Pattern | simplify(ExpressionVisitor visitor) - Simplify the pattern: perform any context-independent optimisations
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allocateSlots , analyze , getColumnNumber , getDefaultPriority , getDependencies , getExecutable , getFingerprint , getHostLanguage , getLineNumber , getLocationProvider , getNodeKind , getNodeTest , getPublicId , getSystemId , internalMatches , iterateSubExpressions , make , makeSearchExpression , matches , promote , replaceSubExpression , selectNodes , setExecutable , setLineNumber , setOriginalText , setSystemId , simplify , toString |
ancestorPattern
public Pattern ancestorPattern
firstElementPattern
protected boolean firstElementPattern
lastElementPattern
protected boolean lastElementPattern
numberOfFilters
protected int numberOfFilters
parentPattern
public Pattern parentPattern
specialFilter
protected boolean specialFilter
LocationPathPattern
public LocationPathPattern()
addFilter
public void addFilter(Expression filter)
Add a filter to the pattern (while under construction)
filter
- The predicate (a boolean expression or numeric expression) to be added
allocateSlots
public int allocateSlots(ExpressionContext env,
int nextFree)
Allocate slots to any variables used within the pattern
- allocateSlots in interface Pattern
env
- the static context in the XSLT stylesheetnextFree
- the next slot that is free to be allocated
- the next slot that is free to be allocated
analyze
public Pattern analyze(ExpressionVisitor visitor,
ItemType contextItemType)
throws XPathException
Type-check the pattern, performing any type-dependent optimizations.
- analyze in interface Pattern
visitor
- an expression visitorcontextItemType
- the type of the context item at the point where the pattern appears
getAncestorPattern
public Pattern getAncestorPattern()
Get the pattern applying to an ancestor node, if there is one
- the ancestor pattern, for example if the pattern is a/b[1]//c then the ancestor
pattern is a/b[1]
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.
- getDependencies in interface Pattern
getFilters
public Expression[] getFilters()
Get the filters assocated with the last step in the pattern
- an array of expression holding the filter predicates in order
getFingerprint
public int getFingerprint()
Determine the fingerprint of nodes to which this pattern applies.
Used for optimisation.
- getFingerprint in interface Pattern
- the fingerprint of nodes matched by this pattern.
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
- getNodeKind in interface Pattern
- the type of node matched by this pattern. e.g. Node.ELEMENT or Node.TEXT
getNodeTest
public NodeTest getNodeTest()
Get a NodeTest that all the nodes matching this pattern must satisfy
- getNodeTest in interface Pattern
getParentPattern
public Pattern getParentPattern()
Get the pattern applying to the parent node, if there is one
- the parent pattern, for example if the pattern is a/b[1]/c then the parent
pattern is a/b[1]
iterateSubExpressions
public Iterator iterateSubExpressions()
Iterate over the subexpressions within this pattern
- iterateSubExpressions in interface Pattern
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.
- promote in interface Pattern
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
resolveCurrent
public void resolveCurrent(LetExpression let,
PromotionOffer offer)
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
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 reference
setExecutable
public void setExecutable(Executable executable)
Set the executable containing this pattern
- setExecutable in interface Pattern
executable
- the executable