Package net.sf.saxon.pattern
Class LocationPathPattern
java.lang.Object
net.sf.saxon.pattern.Pattern
net.sf.saxon.pattern.LocationPathPattern
- All Implemented Interfaces:
Serializable
,SourceLocator
,Container
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:
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected Expression
protected Expression[]
protected boolean
protected boolean
protected int
protected boolean
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
addFilter
(Expression filter) Add a filter to the pattern (while under construction)analyze
(StaticContext env, ItemType contextItemType) Type-check the pattern, performing any type-dependent optimizations.int
Get the dependencies of the pattern.int
Determine the fingerprint of nodes to which this pattern applies.int
Determine the types of nodes to which this pattern applies.Get a NodeTest that all the nodes matching this pattern must satisfyprotected boolean
internalMatches
(NodeInfo node, XPathContext context) Test whether the pattern matches, but without changing the current() nodeIterate 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) 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 variablesimplify
(StaticContext env) Simplify the pattern: perform any context-independent optimisationsMethods inherited from class net.sf.saxon.pattern.Pattern
getColumnNumber, getDefaultPriority, getExecutable, getHostLanguage, getLineNumber, getLocationProvider, getPublicId, getSystemId, make, setExecutable, setLineNumber, setOriginalText, setSystemId, toString
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Field Details
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parentPattern
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ancestorPattern
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nodeTest
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filters
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numberOfFilters
protected int numberOfFilters -
equivalentExpr
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firstElementPattern
protected boolean firstElementPattern -
lastElementPattern
protected boolean lastElementPattern -
specialFilter
protected boolean specialFilter
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Constructor Details
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LocationPathPattern
public LocationPathPattern()
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Method Details
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addFilter
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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simplify
Simplify the pattern: perform any context-independent optimisations- Overrides:
simplify
in classPattern
- Returns:
- the optimised Pattern
- Throws:
XPathException
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analyze
Type-check the pattern, performing any type-dependent optimizations.- Overrides:
analyze
in classPattern
- 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
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iterateSubExpressions
Iterate over the subexpressions within this pattern- Overrides:
iterateSubExpressions
in classPattern
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replaceSubExpression
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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promote
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
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
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
Get a NodeTest that all the nodes matching this pattern must satisfy- Specified by:
getNodeTest
in classPattern
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resolveCurrent
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 reference- Throws:
XPathException
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